Webasto Valves

[jimshoen]

Finally took the time to figure out how my Webasto system works. This coach has three switches that cause the Webasto to fire off.

1) On the Marathon dash there is a switch call 'System Heat'. When this switch is pushed the Webasto fires and the small pump inside the Webasto circulates hot water through the two 10 gallon water heaters and now we have hot water.

2) There is a switch in the main electrical panel in the rear (bedroom) that says '12 Volt Water Heater'. Push that switch and the exact same thing happens as in #1. Interesting?

3) There is another switch in the main electrical panel in the rear (bedroom) that says '12 Volt Heat'. When this switch is pushed the Webasto fires and the small pump inside the Webasto circulates hot water through the two 10 gallon water heaters. Also, if any of the three heat exchangers in the coach that use the hot water for heat are calling for heat a solenoid valve opens and another aux pump in the spare tire area turns on which circulates hot water through all three of the interior heat exchangers. Now we can heat the inside of the coach. Nice!

That left me with only one more thing to figure out, how does the Webasto pre heat the engine. Well, after hunting all around I finally determined that in this coach the Webasto does NOT pre heat the engine. The Webasto system picks up and delivers coolant to the line that connects the coolant surge tank to the water pump (engine). By pure coincidence some of the heated coolant makes it down to the Water pump and warms it up. This was real informative beacause for the last year I believed the Webasto pre heated the engine.

All is not lost as the coach is equiped with a 120 volt block heater which works good. Mystery solved.

Below are a couple pictures of the three valves located at the Webasto unit. I'd like to confirm that these are just solenoid valves and not pumps?

[gmcbuffalo]

Ji
my vote is solenoid valves.
GregM

[Joe Cannarozzi]

I would be very suprised if that was not set up to preheat the engine.

[truk4u]

Jim,

I think you'll find the engine pre-heat to be in the loop. On my 97, when the 12 heat was selected (heat exchangers), it also circulated coolant through the engine.

You also should have a breaker in the 120v panel in the bedroom marked Block Heater. On mine, that breaker controlled the electrical box in the engine compartment that the block heater is plugged into. With the block heater unplugged, it made a great place to plug in a 3 stage charger for the chassis batteries and if the bus was going to set for a month or two, I would just through the breaker and keep the batteries topped off.

[Jon Wehrenberg]

No need to guess. Fire it off and after a few minutes feel around the engine, probably the water pump area is best. You will know if the engine is in the loop.

[jimshoen]

Joe. I am surprised too. I always thought Webasto equals engine pre heat?

Jim and Jon. Ran the system and the engine does not get warm. Can not find any plumbing that would allow Webasto heated coolant to circulate through the engine.

Jim. Yes there is an electrical outlet (GFI Duplex) connected to the 'Block Heater' circuit breaker in the engine compartment and it works now that I replaced the GFI duplex. The electric block heater that plugs into it works well and does pre heat the block when turned on and plugged in. I do have a 24 volt battery maintainer that I plug in there when the coach is stored and it keeps the chassis batteries up.

Jon. Of the three valves located with the Webasto, two have a round body (see the top right and bottom right pictures) and one has a square body (see the bottom left picture). Could the two round bodied units also be circulation pumps?

[Ray Davis]

1) On the Marathon dash there is a switch call 'System Heat'. When this switch is pushed the Webasto fires and the small pump inside the Webasto circulates hot water through the two 10 gallon water heaters and now we have hot water.

2) There is a switch in the main electrical panel in the rear (bedroom) that says '12 Volt Water Heater'. Push that switch and the exact same thing happens as in #1. Interesting?


Where is the "System Heat" switch. I don't recall seeing that on my Marathon. I do have the 12 Water Heater, which does exactly as you describe, but if there's anothe switch, I'd be at least interested to know.

Ray

[Jon Wehrenberg]

Jim,

They all look like solenoid operated diaphragm valves.

I have pushed for this before, and maybe if we as a group can get some critical mass we can do converter specific seminars.

I diagrammed my Webasto system, but the fact that it is a Liberty and virtually all Libertys have OTR air makes the learning of my system of no value to any but other Liberty owners.

Each type of conversion needs somebody to volunteer as the guru who learns the systems and teaches about them.

[jack14r]

Call Leon at Marathon,he will verify how the system works.

[gmcbuffalo]

Jim could one of the solenoid not be working and allowing heat water reaching the engine. Have someone turn the system on while you feel of movement in the solenoid. Or are they getting current? or jump voltage to it and see if they work.
Greg

[jimshoen]

When Adam DeGraff stopped in Reno he showed me the Marathon Owners Manual that came with his coach. Unfortunately, my coach did not come with this manual when I bought it. I did not even know I did not have it. Called Marathon and they sent me a replacement manual, thank you.
Anyway, in the manual is the schematic of the Wabasto plumbing system, valves, etc. After looking at the diagram, I realized that my Wabasto system should preheat the engine. Up to now I was never able to determine why it would not preheat the engine and concluded it was not suppose to. Well I was wrong on that.
Turns out the two 24 volt solenoid operated Parker valves immediately aft of the Wabasto were inop.
After much searching and parts shopping I was able to rebuild the entire manifold that these two valves were part of. Additionally, I added three ball valve shut offs, and Y type strains ahead of the valves. Apparently, it is not uncommon for debris in the coolant system to gum up and clog these valves. These two valves sit at one of the lowest points on the system, probably adding to the collection of junk. See photos.
So I have to retract my original post claiming that my Wabasto did not preheat the engine. It does, however my valves were inop. See photos.

[jimshoen]

Two more photos.

[dalej]

Jim, looks like you did a really neat and complete job there. Should we guess what all the copper cost?

[Joe Cannarozzi]

CC uses those same solenoids to turn the plumbing bay loop on and off and also use them for the auto fresh water drain system and for the fresh water fill.

What did you give for them. I just bought a goyden for 135.

[truk4u]

Nice job Jim!;)

[jimshoen]

About 160 for all the brass and bronze. Valves about 125-150.

[adamdegraff]

Jim, having seen your work in person, I can say that you really added some value to that coach of yours. Forget the gold leafing and your fancy white roof... your webasto is a monster.

I can't believe how gummed up your old valves were. My coach is a year and a half older... I can hardly imagine what mine must look like. No wonder they don't work correctly. Are you sure those aren't black water valves? :D

Any chance you would want to post part names/numbers, quantities and phone numbers to the places you ordered from? Did you say you got the valves on ebay? I'm thinking that I'd like to emulate the King and install the exact same system. I mean... since you did all that leg work.

Awesome!

~Adam

[Jon Wehrenberg]

The "gum" is silicone dropout. Maintaining the coolant, changing it on the prescribed schedule and keeping the SCAs where they need to be all contribute to preventing crud from screwing up the cooling system.

If the valves are gunked up, imagine what all the other valves in the system look like. Imagine what the radiator core looks like.

I saw first hand how our cooling systems are quickly compromised on my first coach even though I did the required coolant changes. On my previous coach there was a sediment bowl on the evaporator coil side of coach (OTR) in the AC bay. That bowl was like the canary in the mine. During routine maintenance Prevost recommended removing it and checking for any sediment. There was always some "slime" in that bowl. I'm not sure the series 60 cooling system is as easily affected as the one on the 8V92 engines, but I'm sure they are affected.

[jimshoen]

Jon, The first thing I did when I bought this coach was to have the coolant replaced etc. At this point the radiator has not caused any problems, however your comments are coming in 5 by 5. Additionally, I did rebuild in place the other Parker solenoid valve which is set just forward of the Wabasto and about 18 inches higher that the other valves. This particular valve was working fine, but after seeing the other two I had to tear into it. Amazingly it was it perfect shape. I still replaced all the inards with new.

[merle&louise]

What do you guys think of the Enviro-Clean spin on filters? Someone posted about them a while back but I can't remember who posted it. They are supposed to clean your radiator while you drive down the road. Snake oil?:eek:

[dalej]

I will let you know Tuga. I ordered and received it in, but won't leave for AZ for a couple of months. It needs 2-3 thousand miles to do the job. I have talked to the company Pres. and he said that it has been in the testing for a few years with bus transit companies.

I'm hopeful that it works great. It releases chemicals at 130 degrees to melt away the build up in the engine radiator and other areas that build up with deposits.

[Gary & Peggy Stevens]

Dale, what is the ordering phone number or web site for this product?

I am getting ready to replace my coolant and filters, should I consider using one of these filters?

Jon, do you have any comments on this product?

Gary S.

[dalej]

http://www.ecfilter.com/

The filter is around 45.

I don't like saying to much about a product until I have used it. I will report on my use of it around April after I have cut up the used filter and seen what it looks like.

The theory behind it is you can change coolant but you can't clean the tiny parts of a system that restrict flow.

[adamdegraff]

Let me get this straight...

this product is purported to filter the gunk out of the system? If it works, I want me one of these! Correct me if I'm wrong, but the filter we have on now "conditions" the coolant. (adds additives?) Right? Would there be a negative to putting on the gunk filer in place of conditioning the coolant?

Just curious.

[dalej]

This filter will add chemicals to the coolant to desolve the solids that have built up over time.

If you measure your coolant with a test strip and balance the coolant to the proper levels, then you can replace the filter that you have with a envro-cool filter and use it for 2-3 thousand miles and then go back to the filter you have now.

George the owner of the company said to use his filter every couple of years for 2-3 thousand miles.

[merle&louise]

Dale,

I purchased 2 of these filters and installed one and ran it for 10,000 miles which is per the instructions. I changed my anti-freeze last month and installed a PowerCool filter with the granules in it. Engine runs cool.

I really haven't noticed any difference, but I was not having a problem with overheating in the first place. I just put the Enviro filter on to clean the system out as a pre-caution.

[Ray Davis]

Which brings up my question. How will no know if it worked, or not? Other than taking apart your radiator, or at least getting somewhat down in there, it seems hard to determine how well it will work?

Ray

[dalej]

I will cut the filter up after we get home from the southwest. I will take photos and post them. There should be a lot of gunk in there since my temps are getting higher in the summer and in hills.

[Jon Wehrenberg]

Dale,

You are seeing the beginning of the end unless this is a good product.

The tubes in the radiator become blocked, not only reducing the flow, but insulating the coolant so the radiator simultaneously becomes less efficient at transferring heat. That is the classic type of failure and is especially characteristic of 8V92 radiators.

That will be the acid test. The picture I want to see is one of the radiator tubes before the filter and of the tubes after.

In the meantime start looking for someone to recore your radiator.

[Gary & Peggy Stevens]

I may be gullible too, but I ordered one of the Filters today. ( If it is good enough for Dale it is good enough for me )

I told George the tech, that I was getting ready to change out the coolant, and should I put his filter on before I change out the fluid or after?

He said absolutlely his filter before I replace the fluid with new. Run bus for 2-3 months or 3000 miles and then remove and replace all fluids/filter.

His filter and chemicals are suppose to really clean the gunk out of the radiator and engine system, trap it in his 10micron filter and then you throw that filter away, and replace with all new fluid and regular filter.

Sounded good to me ? :o

Gary S.

[Darrell McCarley]

Has this ever happened to anyone else in POG or am I the only dummy in this group? Beginning about 12 mo ago, my 8v92 began to heat up during the Texas summers and western mountains geting up to 195 on level surfaces and 205 in mountains. I changed out the thermostats for $400.00, test drove , no fix. Changed out the radiator at $2200.00. Test drrove, no fix. Changed out the water pump for $400.00, test drove, no fix. Changed out the oil coolers for $1600.00, test drove, no fix. I was clueless on what to do next so I decided to go Stewart & Stevenson to visit with the service manager explaning my overheating problems and the things I had done to try to correct this problem. He said, why don't we take a look. I opened up the rear engine doors and he said, here is your problem right here pointing to a loose radiator fan belt. He could not get me scheduled for several days and suggested that I go to Prevost DFW. The tension air valve release that tightens the fan belt became clogged with a white chrystal like substance from the air system. All of this expense and a complete fix for $37.00 plus Prevost labor. This is not the first time that I have replaced part after part until it is repaired. Anyone have a similiar story?.............Darrell

[dalej]

I take it you did all this before you joined POG

[Jon Wehrenberg]

Darrell,

Why do you think a lot of us have started doing our own work. I'm assuming you paid someone to do all those repairs, and if any of them were either honest or competent they would have alerted you to the lack of belt tension.

BTW, if you think that is bad, take your coach to have someone cure the leans.

[Darrell McCarley]

Dale.......No, after I joined POG. No excuses........Darrell

[Jon Wehrenberg]

Why apologize? It isn't like you did anything wrong. If anyone did anything wrong it is the technicians who screwed up their analysis of the cause.

[Darrell McCarley]

JON....I had the leans several years ago. Went to Prevost for a cure to no avail. Still have a slight case of leans but have learned to live with it......Darrell

[Jon Wehrenberg]

Until Hector really got into it and made his power point program the air suspension systems were a black art.

Today, with the knowledge here, and with the guidance of Hector's power point program there is no need for any POG member to have the leans, or to spend serious dollars getting them cured.

Where is it leaning, what year coach, who is the converter, and I'll bet we can isolate the areas that cause your problem.

[Darrell McCarley]

JON.....That was my problem. I did my own analysis and then had the repair shop do the repairs. Next time, Maybe I will let the professionals do the analysis. On second thought, I will probally do the next analysis myself. Some of us never learn.........Darrell

[truk4u]

Darrell,

Year and conversion like Jon said would help.

[Jon Wehrenberg]

I would agree the techs were blameless except for a couple of things. Maybe they can change the thermostats (2) on an 8V92 without touching the fan belt, but they cannot work in that area for the amount of time required to change the thermostats without noticing belt tension.

I may be wrong but if I was a mechanic and I was asked to replace thermostats, surely I would ask why. It would be unusual for thermostats to fail in such a way as to slowly allow your engine temps to increase.

Then as a mechanic who is both lazy and simple minded, I would start looking for the cause of your symptoms starting with the most basic stuff........like belts and tension.

[dreamchasers]

Until Hector really got into it and made his power point program the air suspension systems were a black art.

Today, with the knowledge here, and with the guidance of Hector's power point program there is no need for any POG member to have the leans, or to spend serious dollars getting them cured.

Where is it leaning, what year coach, who is the converter, and I'll bet we can isolate the areas that cause your problem.


Jon,

I finally solved my air leak problem with the braking system and for the first time since I have owned the coach, the tag axle does not dump overnight due to loss of air. I have learned 'mucho' about the air systems. I have been thinking of developing another interactive learning tool for the primary, secondary and auxiliary air systems.

Are you up to acting as a technical advisor again?

Hector

[Darrell McCarley]

JON & TOM.......1989 Executive Coach Conversion(Fox River Grove, Il) out of business. 144K total miles. The left side air bags start to lean after 5-7 days in warm weather and less time during winter months here in Dallas, Tx. I have not been concerned because it does not leak down while driving. I have another problem that I could use some advice. I have 12v/24v house batteries with a cross-over switch to connect the house batteries with the engine start batteries. I leave this switch on when parked and pluged in to keep all batteries charged including engine start batteries. I also leave the switch on when driving to keep my house batteries charged. The cross-over switch is getting power to the silenoid (in and out) but no power to the rear engine start batteries. What could cause this problem?

[Jon Wehrenberg]

Hector,

Let's do it. I have found when explaining the suspension system that most look upon it as a big, huge complex assemblage. To aid in understanding I ask folks to think instead of three separate unrelated systems that share a common connection to the aux. air. Then when trouble shooting it becomes easy for everybody to focus exclusively on only the components within the sub-system.

My point is that the diagramming and teaching of the other pneumatic systems should be done in small blocks. For example, the rear brakes could be broken out and isolated so the system starting with the relay valve could be shown. The "signal" system from the foot treadle could be another block. Another could be the daisy chain of pressure tanks starting at the compressor. I think compared to the suspension system which has a lot of variations the primary and secondary air systems can be a generic presentation with almost universal applicability.

I know nothing about the ABS so I am not sure how to integrate that. I suspect that goes beyond what most want to get involved in, beyond flashing or reading the codes. I think most problems on ABS have to do with failed sensors anyway.

[Jon Wehrenberg]

JON & TOM.......1989 Executive Coach Conversion(Fox River Grove, Il) out of business. 144K total miles. The left side air bags start to lean after 5-7 days in warm weather and less time during winter months here in Dallas, Tx. I have not been concerned because it does not leak down while driving. I have another problem that I could use some advice. I have 12v/24v house batteries with a cross-over switch to connect the house batteries with the engine start batteries. I leave this switch on when parked and pluged in to keep all batteries charged including engine start batteries. I also leave the switch on when driving to keep my house batteries charged. The cross-over switch is getting power to the silenoid (in and out) but no power to the rear engine start batteries. What could cause this problem?


Darrell,

The Prevost standard for acceptability is if the coach does not lean in 3 days it is OK. That does not mean that you will accept that. Without knowing your coach's service history, or age of the components, there are a relatively few areas where your coach can be leaking, and with the slow rate the leak(s) may be difficult to find. If I wanted to trouble shoot the problem I would start by soaping the three air bags. That would not tell if the leaks are around the bottom "can" but it would rule out the top crimp, and any porosity in the rubber.

I would soap all the fittings on the three air bags, on the three port Norgren on the frame between the tag and drive, up high on the frame, and the 5 port Norgren in front of the drive axle fender liner.

Then I would use a stethoscope or ultrasonic leak detector to listen carefully at the five port Norgren in particular. With a leak as small as you have I would remove the air supply line from the ride height valve and the line to the three port valve in the front and cap both of those ports. (Air leaking sideways past the spools in the Norgrens would show up as bubbles at the end caps, but air leaking past the "o" ring to the exhaust would not because it is an internal leak) By plugging the two ports if the bus does not lean the problem is with the 5 port valve, if it leans a more extensive check of the air bags is likely to find it.

Now you know more than you ever wanted to know about how to chase that last leaking bubble of air. Or you could use Hector's bubble detector. He did promise to supply a drawing or a how to description of making one and using it.

Your bus is leaking down when you drive, but the leak is so small it is easily compensated for by the ride height valves. Cold weather always makes small system leaks more visible.

I would need to know more about how your converter set up the coach to fully address your question about the "cross over" switch. Generally converters try to keep the house and chassis batteries isolated from one another. The solenoid you mention could have been provided to tie the two sets together when you have charging current from your alternator(s) so both sets can be charged, or to provide you with a means to boost your chassis batteries in the even they don't have the power to start the bus.

Your chassis batteries should not run down when you do not heve the engine running. If they do there are loads on the batteries that should not be there, or you have bad batteries. I suggest you check for each problem.

As to why the solenoid is not getting power to the batteries may be as simple as a bad solenoid. It's an easy check to confirm that if the solenoid is getting power to the two connections to the coil, then there should be continuity between the big posts. I am assuming this is one of the silver solenoids such as you might find on the firewall of an older car.

[Darrell McCarley]

Thanks JON......The solenoid has two solenoids connected together with a copper strip. Both solenoids have 24v power from both sides with the dash switch activated. I must have another solenoid or connection further back toward the engine that is not making contact. When my friends shop pit becomes available, I'm getting under the bus to trace the battery cable from the house battery compartment to the engine batteries. Could be simple as a corroded battery connection. Thanks again for your input......Darrell

[Ray Davis]

Turns out the two 24 volt solenoid operated Parker valves immediately aft of the Wabasto were inop.

Jim, I finally got to check out my webasto this weekend, and I believe I am seeing the same issue that Adam has. AND, I believe you hit the nail on the head with respect to our problem.

In Adam's case, and it turns out, in my case the heater shutdown down, unless "Block Heat" is enabled. Well, in looking at the schematic, and feeling around for hot coolant in pipes, I've decided that the normally-open return valve is clogged up. When you use block heat, these two return valves are reversed, and coolant comes through the engine, and out the other valve back to the pump. That path is working for me and I believe it's working for Adam. It's possible (I'm guessing here), that if the previous owner had not used block heat much, then that valve would have generally been closed, and less susceptible to clogging.

So, I need to rebuild my system similar to yours, although I am not sure I want to add the ball valves. Can you let me know where to find the two valves that are used back there? There should be a normally closed, and one normally open valve, both 24V (in my case).

Thanks in advance.

PS: Contacted Leon about this, and he mentioned that for some of their customers with early era coaches, they are simply removing the guts to the two valves, and letting them both be open. I found this to be interesting news.

Ray

[Ray Davis]

PS: How do you accomplish this rebuild without a total mess? I'd rather not completely drain my coolant from the coach. Is there a way to block off the pipes long enough to swap in new manifold, as you've done here?

Thanks,
Ray

[truk4u]

Ray,

My Liberty heats everything with the Webasto running, engine, hot water heater, bay heat and coach heat exchangers. I like it much better than the previous coach's with buttons to open and close the various loops. Kind of simple, everything is on.

[adamdegraff]

PS: How do you accomplish this rebuild without a total mess? I'd rather not completely drain my coolant from the coach. Is there a way to block off the pipes long enough to swap in new manifold, as you've done here?

Thanks,
Ray

Ray, I got the low down on doing it without mess. There is a tool called "Hose Pinch Off Pliers." I am sitting with it on my lap right now. Napa #145. You will need three of them to isolate the area where you will be working. The hoses are reputed to be difficult to collapse. So I went with this higher end tool (about $25) that ratchets down and locks in place. I supposed a pair of vice grips or a pair of channel lock pliers might also work... but I really, REALLY don't want to damage my hoses. Once you have it all pinched off, Jim Purcell (over at Marathon) told me to prepare to do battle with the big round valve cover. He said it is a bitch to get off. It is also huge. I have a massive pipe wrench that should do the trick and provide the necessary leverage assuming I can get to it.

I'll let you know how it goes... once I find two more of the pinch off pliers. I tell you, being on the move 100% of the time makes it hard to mail order things. So I'm hitting NAPAs on my route and picking up the necessary tools. I'm thinking that once I get the valve open, I will just clean out the screen and put it all back. I assume the screen is there for a reason? Jim has a nice picture of a gunked up valve so you will know what to expect.

If you go first, let me know how it goes. If I go first, I'll do the same. I'd love a sweet set up like Jim's but don't have the brass to make it all work this time 'round.

Good luck.

Adam

p.s. yes, our problem is exactly the same and yes, you are exactly correct as to the fix. Jim confirmed all of this and seems to know more about this system than does Leon. Leon was certain it was my extra webasto pump located in the cruisair compartment.

[hhoppe]

Thinking out loud here. Could the webasto be getting it's electrical power from the same electrical outlet as the block heater. No block heater switch on, no webasto operation. You need to have working valves or at least manual operated ones to prevent hot water circulation from the engine flowing through the coach unchecked in summer conditions. Each converters schematic is probably different.

[Ray Davis]

Harry.

In my case, and I beleive the same with Adam, our webasto's fire up just fine, but in about 1 minute they are shut down by the overheat thermostat. The reason is the circulation pump is not moving the fluid (either at all, or too slowly). The pump is working, as you can hear it fine, so it's not a power issue.

With the Marathon (at least with mine), there are two paths for the coolant to return through the loop. The "normal" path is through a normal-open solenoid, while a normally-closed solenoid blocks the fluid from going through the engine. When you turn on the block heat, these two solenoid valves are reversed, so the normally-open is now closed, and water flows through the engine, and out through the other solenoid valve, which is open.

In my case, that valve works, and I get flow, and heat, although it is slower to heat because there is more coolant fluid involved.

If you look at the picture of Jim Shoen's setup the valve on the right side is the normally-open regular return valve. The one on the left is the return that comes through the engine.

Ray