8V92 cooling system

[Woody]

Prevost Jax flushed the entire system and replaced all coolant due to a combination of non mixing coolant put in at DD Lodi.

Problem is when I got to ORA Blur Ridge and tried to leave at 39 degrees F engine cut off after 30 seconds. Found no coolant in expansion tank and no evidence of leak. Prevost added coolant to a hot engine.

Question - is there a sensor in the expansion tank? All was well when I added 1 gallon of the proper coolant and all is well this AM in Va.

[truk4u]

Yes, there is a low coolant sensor in the expansion tank Woody. You should check the site glass for coolant as part of your normal pre-trip.

[Jon Wehrenberg]

I'm surprised Prevost didn't do a better job of filling the system with coolant. Probably the hardest single maintenance item on the bus is draining the coolant which is a real challenge as numerous posts have indicated, but then when drained, it is equally hard burping the system and properly refilling it.

I got a tip from a mechanic I trust and this August when I drain and refill my system, one of the things I am going to do to facilitate filling is to pull a vacuum on the entire cooling system and literally suck the new coolant in. There are numerous models of the device that will create a vacuum on the cooling system available. The one I have I have used on my cars and it is incredible to see the hoses sucked flat and then watch as new coolant is drawn into the cooling system. When done I generally only have to add a cup or less to bring the expansion tank to the proper level.

After changing coolant on the bus it is almost a given that the coolant needs to be checked often until it is evident all air has been burped.

[travelite]

Another tip is to collect and measure the volume of what you drain out and make sure that you put that same volume back in.

[Jon Wehrenberg]

Good luck with that. Trying to measure somewhere between 18 and 24 gallons depending on how successful you are in draining is tough because if you are like me, filling containers to the top means some is going on the floor. I just drain it into a big tub and then try to transfer it into six gallon containers. I have changed coolant about 8 times now on my buses and despite my best efforts I still get a bath in it, or it ends up splashing on the floor, or I seem to end up with more coming out than going back in.

I think Dale was the last one to struggle doing it and I am really looking forward to the EC-1 so I just don't have to mess with coolant as often. I have had great success the last couple of changes using the Webasto system to circulate coolant and to burp the system. I don't think I needed to add a half gallon after I drove it the first time.

[travelite]

Good luck with that. Trying to measure somewhere between 18 and 24 gallons depending on how successful you are in draining is tough because if you are like me, filling containers to the top means some is going on the floor. I just drain it into a big tub and then try to transfer it into six gallon containers. I have changed coolant about 8 times now on my buses and despite my best efforts I still get a bath in it, or it ends up splashing on the floor, or I seem to end up with more coming out than going back in.

Glad you're open to new suggestions Jon. LOL

Collecting into a large 2' x 5' x 10" tray works for me. I then transfer into 5 gal buckets and round up. Using this technique you can get pretty close, within a couple of gallons, of what actually came out. Then you have a pretty good idea, within a couple of gallons, of what should go back in. Top up from there. I just did it with success.

[Jon Wehrenberg]

There's the key. Getting within a couple of gallons means you could likely have a dry expansion tank after a drive and cool down.

The last coolant change I removed and replaced the Webasto hoses in the engine area. That of course created flooding on the floor because there is no drain plug in that area or a single point where the coolant can drop. Even with my big tub under the area coolant ran in every direction across the sheet metal shelf once certain hoses were removed. The good news is I was able to circulate coolant and do a decent job of burping with the Webasto circulating pump after filling and by getting the engine up to temp and the thermostat to open I managed to get it filled so I only had to add about 1/2 gallon after the first drive. One thing I have been doing is never filling past the sight glass. That lets me catch it when the coolant level goes down a little. Once I am sure it is burped I go about a half gallon above the sight glass. That leaves plenty of room for expansion and does not end up puking hot coolant out the cap once up to temperature.

[Woody]

For what it's worth, after 1,100 more miles the one gallon added seems to have done the trick. They didn't miss it by much.