I'll always remember the summer of 2010...

[Devin W]

...as it has been a spendy one. We knew when we bought our bus that we would be due for a few things before long. Of course all of the systems aside from the Webasto heater checked out well from purchase, but we knew that tires would be the first big investment (and of course took that into consideration for what we paid).

Unfortunately, sometimes things hit all at once and we had some down time that started with the engine getting hot. After getting a complete service and having all of the codes checked, we found that the issues persisted so it was time to dive in deeper. That more detailed inspection revealed the need for an new radiator core, as well as a new blower driveshaft and coupler and turbo (or blower) blowoff valve. Of course, all of those are parts that tend to wear and ones that seem to be particularly vulnerable on our motors, so we fixed them and we're ready for the next 100,000 miles.

But not so quick -- as things go, while in for the engine service, we had the generator running at times to power the A/C for the interior work (since the bedroom floor had to be partially dismantled) and, wouldn't you know it, one day while the generator was running it began to smoke. The technician caught it quickly and shut things down and we found the culprit was a bad bearing that allowed the stator to drop and cook a few things (testament to replacing those bearings if you notice any issues). Of course, I look at it as good fortune as 1) I often use the watchdog when we are not connected to shore power and it could have happened when we were away from the coach when a fire might have started 2) the bearing certainly did not fail randomly, so it was near the end of it's life and could have easily failed while we were trying to use the coach. Silver lining...or maybe I should say gold, 'cuz those parts aren't cheap.

Now, we take it in Monday to have the transmission looked at. Everything else is running so well that there is a very apparent hesitation under power that is not related to an actual gear change and after a test ride, my technician believes that there is something awry with the lockup which means possible issues with the torque converter. Based on some readings he got with the TPS there is a tiny glimpse of hope that it might be resolved with programming, but I'm preparing myself for something more significant.

As I've told my wife several times, these are just the things that come around every about 100K miles, so if we like using it we have to take our lumps. The other saving grace is that we've got a really great shop within walking distance of my house that is skilled and so fair when it comes to price that I sometimes worry if he's making enough money to want to see me again. When we bought the coach last November it had 88K miles on it. We now have about 105K, so we're on track for squeezing almost 20% of it's overall miles into it's 16th year of life. One thing that's for sure, these things drive so well, it's a shame not to drive them whenever you can (OK, so the MPG is a bit poor for around town commuting...).

[Will Garner]

Devin,

Just for kicks, and to possibly save some Lewbucks, change all your fuel filters - both primary and secondary filters. It really may be that simple and you may not realize it. They probably need changing anyway.

[Devin W]

Thanks for the tip, Will. I did just have that done with the recent service as I wanted to make sure that all of the potential obvious culprits were taken care of (did the filters on the Webasto, too!).

[Jon Wehrenberg]

I wonder about a few things that got my immediate attention.

The most obvious is that apparently folks are comfortable relying on auto-start for their generators. I know our generators have protection devices, but I still feel very uncomfortable putting my coach in a situation where an unattended mechanical device, especially one that involves fuel and huge amounts of electric, is allowed to function. I wonder if I am alone in my unwillingness to do that? The only time I have done that is at OSH and as luck would have it the genrator threw a belt while I was there. Fortunately the POG pit crew came to the rescue and got me going again.

The second thing that popped out was the age and total miles. Recently we have seen posts relating to coaches that have seen minimal use going through some painful repairs. For years buyers have focussed on low mileage coaches and equally low hour generators. Yet these seem to be the ones that have a shopping list of maladies while the high mileage coach owners just seem to keep on chugging along dealing with routine maintenance. What has been the ownership experience of those with disproportionately low miles and those with unusually high miles? Just curious.

I am presuming Devin's coach is an 8V92 and one of his comments is a reflection of something I have sensed but don't have data to prove beyond my own experience. I think the 8V92 cooling system absolutely, positively has to be properly maintained or the radiator core will be subject to blockage and will require replacement. I believe all our cooling systems require good maintenance, but the 8V92 easpecially so. For potential buyers this is a serious consideration and if proof of maintenance is not provided the price should reflect a radiator exchange.

[Devin W]

John,

You make some good points. We often rely on the watchdog when we are dry "camping" to make sure that the refrigerator doesn't draw the batteries down too low while we may be away during a good portion of the day, but the bearing failure and the fact that I have actually broken two generator belts (the original that was on the coach when I bought it and more recently, one on our last trip) would point to the fact that we could be inviting some serious issues if left unattended. In the case of both gen belts breaking, I was near the coach (although in this condition the system shuts down quickly and aside from lots of coolant puked all over, I'm not sure if there is harm done -- the failed bearing could have been a different story).

As for the mileage, I definitely get the impression that things may wear faster when the bus is used more, but they are less likely to just break or fail without warning. It might be the difference between something aging and becoming fragile and being able to routinely spot wear and replace or repair proactively. Our motor is an 8V92 as you presumed and while that motor seems to be more sensitive to heat, the cooling system also seems to be robust enough that it can be hard to spot an issue until you have one. Our bus ran well at normal operating temperatures for 7 months until the right circumstances collided to really reveal that there was a problem. By the time the core was checked they determined it was 60% occluded. I was probably most shocked that nothing had shown up before based on that finding.

Fortunately, while the repairs have not been cheap, I feel we buffered ourselves well in our original purchase price to where we're able to soak up the maintenance and repair costs to date.

[Jon Wehrenberg]

Devin,

I think there is a sense in some folks that the 8V92 runs hot. My experience has been different than that. My 8V92 ran at 180, and climbing especially long 6% or greater grades in the hottest temps it might get up to 195, but not beyond.

My radiator issues gave substantial warning. A hill I could take at 195 on the hottest days became a 200 degree hill, and then a 205 degree hill at which point I had to act. The cost of running in the rust belt showed up in the form of disintegrated fins. When the radiator was recored the shop told me that it was time to recore because the radiator was also getting blocked and that was despite 2 year coolant changes and 6 month filter changes.

While frequent use my produce wear, I think the greatest wear and associated problems comes from infrequent use. I think if a bus has spent most of its life parked I would expect to see problems with the Norgren valves, hub seals, prematurely aging tires with dry rot, and an engine that has internal cylinder corrosion. From lack of use perhaps algae in the fuel tank and a myriad of other conditions brought about by not exercising the various switches, valves and moving parts.

[Woody]

Jon

You seemed to gag when I said that I started the engine and brought it up to temp once a week. In aircraft I know that ground running is bad but isn't exercising all bus systems a good thing as opposed to my once a month 60 mile drive?

[Jon Wehrenberg]

While just running the engine and getting it up to temp may not be a bad thing (assuming you can actually get it hot enough) it doesn't exercise the transmission, the valves associated with the suspension, the brakes, and the various other parts associated with driving.

I may not have the patience or maybe it is not possible, but anytime I have run the engine from a cold start I have never seen the temp gauge get to the point where it is cycling the thermostat. I think anything short of max normal operating temps might tend to leave moisture in the crankcase.

One thing we were told in seminars by tire experts is our tires have chemical compounding that resists sidewall cracking and aging, but to release those compounds we need to exercise the tires by driving, or as an alternative store them like a tire warehouse does. I presume they mean to get the weight off the tires, something we are unlikely to do when we park for a long term.

[Yankee802]

Jon

You seemed to gag when I said that I started the engine and brought it up to temp once a week. In aircraft I know that ground running is bad but isn't exercising all bus systems a good thing as opposed to my once a month 60 mile drive?

I do this as well, it was the very first (and probably most important) bit of advise I got when I started looking at Prevosts. I guess the question is, is this enough to keep the gremlins away? Jon?

[Jon Wehrenberg]

My reasons for not just running the engine are above.

I feel strongly that if the coach is destined to sit for vey long periods some plan of action to avoid issues due to inactivity should be made. The problem is I don't know what constitutes an unacceptably long period of inactivity and I do not know how to measure if leaving the engine alone is better than starting it periodically. I don't think any of us has the answers because all of our experiences with issues like this are anecdotal. In my plane's handbook it outlines exactly how to preserve the engine during periods of inactivity. I have never seen that for the bus.

Adding immensely to the confusion is the environment the bus is in during inactivity. In my garage which minimizes my coach's exposure to the elements and especially the salt air near the coast I suspect strongly it is less affected by inactivity than one that sees wide temperature swings in humid salt air.

I think we all know a bus with little or no use over a period of time ends up with problems not encountered by one that is used regularly. But take one bus and park it near Tuscon and a second parked in Palm Beach and in my mind it is no contest which one will likely have greater issues. The same goes for coaches used frequently. Drive one exclusively in Texas and a second one in the rust belt and there is no doubt which one will have substantial damage from rust and corrosion.

I do believe strongly (my opinion only) that if as part of the plan to have little or no activity with the bus for an extended period, such as six months or more, part of the plan will be to do several things at least once a month. First, when parked I will support the chassis with stands and dump all the suspension air pressure to get most weight off the tires. I might even raise the axles so the tires are not in contact with the floor or ground. Next I would shut it down electrically. If I wanted routine access and needed electric i would make sure the inverrters were on and I would monitor them at least daily.

Once a month I would drive it. I have a loop near my house that would allow me to get everything up to normal operating temperatures and all moving parts exercised and lubricated. The distance is about 16 miles but it has enough slope to it that the engine and transmission both reach their max normal operating temps. Getting up my driveway and into my garage requires that I both raise my bus and lower it so the suspension is getting exercised over its full range which keeps the Norgren valves operational. Doing that is a PITA, but so is replacing an engine with internal corrosion, or replacing Norgren valves that leak because the seals sat in one spot and corroded the polished aluminum interior of the valve. In case that doesn't make sense is there anyone that has not had to hit reverse just to get the brakes to release after the bus sat in humid conditions for a while? (That might not apply to disc brakes, but drum brakes "freeze")

If on the other hand the bus will sit 3 months.....I don't think I will do any of the above, but bear in mind I always have the bus on stands when in the garage so I can go under it if I get the urge without worrying if it will come down unexpectedly. If the inactivity is in a campground I would definitely drive it some distance because I couldn't get the weight off the tires so I would want to exercise them. The question is how long is too long to sit and I see so many variables that I can't think of any answer that fits all situations.