8V92TA Thermostats

muldoonman · March 05, 2016, 09:49:13 AM

My 1991 Prevost XL with 83,000 miles on it typically runs about 195 degrees and will hit 200 degrees in summer pulling hills with Ford Pickup toad and wanted to know if thermostat change to lower temp would help. Reading about this heat and the 2 strokes not liking it above 195 degrees scares me. Bought coach and it had 52,000 miles about 6 years back. Don't know what's in it as coach was bought new from Prevost and shipped to Wyoming for conversion in 1992. Has never had any work on engine and radiator was checked out and antifreeze changed by Prevost a couple years ago. It runs about 5 degrees cooler at back gauge. Is it worth a change to lower thermostats?

eagle19952 · March 05, 2016, 09:52:42 AM

It really doesn't matter at what temp the tstat opens...

muldoonman · March 05, 2016, 10:14:23 AM

Yeah I guess it wouldn't. I figure if there full open it a flowing. Thanks.

krcevs · March 06, 2016, 08:35:23 AM

I would suggest that you have a look in the bottom of your radiator and make sure you don't have a issue plugging it up. It will be a white deposit on the radiator core. Stewart and Stevenson out here in Colorado suggested that only Fleet Guard (Detroit) and Fleet Charge (NAPA)coolant was to be used due to a silica dropout issue with the other brands of antifreeze/coolant. I have had to pull radiators out and have them rebuilt due to them being plugged up with the silica buildup.

HTH Ken

luvrbus · March 06, 2016, 08:46:05 AM

Glen, you are ok they operate normally at 185 to 197 degrees, it sounds like your system is in good shape,most had 185 t stats

eagle19952 · March 06, 2016, 09:47:04 AM

Quote from: luvrbus on March 06, 2016, 08:46:05 AM
Glen, you are ok they operate normally at 185 to 197 degrees, it sounds like your system is in good shape,most had 185 t stats

I think you are ok to, especially if you have a 8v92.... in which case you are doing very good. Most/many can't run those even that cool.

muldoonman · March 06, 2016, 01:09:02 PM

Thanks guys. Just a wondering.

Skykingrob · March 06, 2016, 06:07:51 PM

I am like Glen in that I have a 91 Prevost XL with an 8V. Mine runs about the same temps as his and has 86K miles since new. I do know it was a casino runner on the Vegas strip for a time, don't know how long. The company that had it went bankrupt and it set on a lot in Vegas for about 5-7 years before being sold in an auction to a casino runner in Jacksonville FL. That company went bankrupt 8 mos after owning the coach. I bought it off eBay. The owner said it was "updated" but when asked couldn't tell specifically what was "updated". I could tell it had brand new Firestone tires all the way around, otherwise there were no outward signs of anything being done. I don't have any idea of the history on the coach including fluid changes etc. Right after I got it, I changed the antifreeze. I went to the local Detriot Dealer to get their brand but the service manager told me to go buy the "green stuff" at local auto parts store. I ask him if Fleet Guard was better. He said yes but it was not necessary. I still put the Detroit Fleet Guard in it.
I, like Glen, wonder about it. I also wonder if it wouldn't be good preventative to remove the radiator and have it inspected and cleaned/recored if necessary as I am told the older radiators were bad about deteriorating internally without outward signs except higher temps until they failed, often cooking the engine.

Rob
91 XL 40
Missouri

eagle19952 · March 06, 2016, 07:06:48 PM

Quote from: Skykingrob on March 06, 2016, 06:07:51 PM
I am like Glen in that I have a 91 Prevost XL with an 8V. Mine runs about the same temps as his and has 86K miles since new. I do know it was a casino runner on the Vegas strip for a time, don't know how long. The company that had it went bankrupt and it set on a lot in Vegas for about 5-7 years before being sold in an auction to a casino runner in Jacksonville FL. That company went bankrupt 8 mos after owning the coach. I bought it off eBay. The owner said it was "updated" but when asked couldn't tell specifically what was "updated". I could tell it had brand new Firestone tires all the way around, otherwise there were no outward signs of anything being done. I don't have any idea of the history on the coach including fluid changes etc. Right after I got it, I changed the antifreeze. I went to the local Detriot Dealer to get their brand but the service manager told me to go buy the "green stuff" at local auto parts store. I ask him if Fleet Guard was better. He said yes but it was not necessary. I still put the Detroit Fleet Guard in it.
I, like Glen, wonder about it. I also wonder if it wouldn't be good preventative to remove the radiator and have it inspected and cleaned/recored if necessary as I am told the older radiators were bad about deteriorating internally without outward signs except higher temps until they failed, often cooking the engine.

Rob
91 XL 40
Missouri

all of which becomes a no worry affair if you have and maintain a overtemp low coolant low oil pressure shut down. in my opinion the most crucial and critically necessary system on a coach.... like the cat lady, the next thing is a driver with a full understanding of what the heck is going on.

luvrbus · March 07, 2016, 07:01:34 AM

If both have DDEC engines it will take care of the engine, it is hard for someone to kill a DDEC engine it takes a lot of work on their (driver) part

muldoonman · March 07, 2016, 10:50:54 AM

Quote from: luvrbus on March 07, 2016, 07:01:34 AM
If both have DDEC engines it will take care of the engine, it is hard for someone to kill a DDEC engine it takes a lot of work on their (driver) part

Yeah mine shut down a couple years ago after Prevost changed out antifreeze when they didn't get all the air out of it. Low coolant in surge tank. Idiots like me need that safety shut down for sure.

Iceni John · March 07, 2016, 12:05:32 PM

Quote from: Skykingrob on March 06, 2016, 06:07:51 PM
I am like Glen in that I have a 91 Prevost XL with an 8V. Mine runs about the same temps as his and has 86K miles since new. I do know it was a casino runner on the Vegas strip for a time, don't know how long. The company that had it went bankrupt and it set on a lot in Vegas for about 5-7 years before being sold in an auction to a casino runner in Jacksonville FL. That company went bankrupt 8 mos after owning the coach. I bought it off eBay. The owner said it was "updated" but when asked couldn't tell specifically what was "updated". I could tell it had brand new Firestone tires all the way around, otherwise there were no outward signs of anything being done. I don't have any idea of the history on the coach including fluid changes etc. Right after I got it, I changed the antifreeze. I went to the local Detriot Dealer to get their brand but the service manager told me to go buy the "green stuff" at local auto parts store. I ask him if Fleet Guard was better. He said yes but it was not necessary. I still put the Detroit Fleet Guard in it.
I, like Glen, wonder about it. I also wonder if it wouldn't be good preventative to remove the radiator and have it inspected and cleaned/recored if necessary as I am told the older radiators were bad about deteriorating internally without outward signs except higher temps until they failed, often cooking the engine.

Rob
91 XL 40
Missouri

My radiator has a cool spot in it, presumably from an internal blockage. At the very least it will need to be rodded through, but if I'm going to the trouble of removing it I might as well just recore it with the highest heat-rejection core I can get, and also put in a modern multi-blade fan to pull more air through it. I'll talk to Stanton Radiator, and also find out where the local school districts get their radiator work done.

John

eagle19952 · March 07, 2016, 12:30:33 PM

we had a lot of good service from these...anyone ever had one built for a coach. ?

http://www.mesabi.com/products.php

Skykingrob · March 08, 2016, 11:12:20 AM

My auto shut down still works. I had a pin hole leak in one of the backside engine hoses that I didn't notice. When it leaked enough to hit the low sensor in the surge tank it shut the engine down. I haven't had it shut down for over temp but I try very hard, by using throttle input, to keep the temp down below 200.

Rob
91 Prevost
Springfield, MO