Thermostats---cooling

[Busnut83]

Just wanted to see if anyone,,,6v92ta mc-9,,, with the overheating problems,,,  changed to the 170 thermo
and got better cooling.... This is what the shop wants to try next.... 3-4 hrs labor + thermos and coolant...

[TomC]

If you're engine is slowly heating up, having a 170 thermostat might delay the overheating by a few miles.  Instead of doing the bandaid, spend the money to have the radiator cleaned out on the interior.  Besides, 3-4 hours labor to change two thermostats and the coolant is way out of line. I'd believe 1-1.5 hrs.  Good Luck, TomC

[TomCat]

Just wanted to see if anyone,,,6v92ta mc-9,,, with the overheating problems,,,  changed to the 170 thermo
and got better cooling.... This is what the shop wants to try next.... 3-4 hrs labor + thermos and coolant...

Sounds like that could get expensive quick!

Jay
87 SaftLiner

[Don4107]

Unless the problem IS the thermostats, I don't think it will help.  If the existing thermostats are working they are wide open when hot anyway, just like the 170s would be.  I would stay with stock temp stats too.  170 is a bit too cool to run.

How does it heat up?  Is it a problem only when pulling hard?  Does it overheat just cruising down the road?  What have you tried so far?  What coolant mix are you running?

Good luck

Don 4107

[Busnut83]

This is the 3rd year,,, I have posted many times this problem,,, only when running60-70mph... When the shut-off and bell comes on,,, before I can change lanes and pull over,, it start up and has cooled down--45sec...

I have new rad,,, new 210* shut-offs,,,ABC company anti-freeze-pre-mix....

The top of the rad temp is about 195*,,, the bottom is 145*.... the engine is 210 -225 at different locations.... I use a laser temp gun...

[Busnut83]

Also williams co ran a rack,,, new injectors set at 1.460,,,

[TomC]

Almost sounds like you have either a cracked head or a blown head gasket that is allowing hot combustion gases into the coolant-since when it quits, it cools down quickly.  Might have a gas test with the engine running to see if you have a leak.  Good Luck, TomC

[Don Fairchild]

the temp across the radiator sounds about right but here are some things to check.
I would look at the water pump and see if the impeller is slipping on the shaft and I would take the radiator cap if you have one and have it tested. Should be around 7lbs,also look at the seal on the cap, if you are looseing coolant and have a surge can I would look at the overflow bellows and cap as well as check for combustion gases as tom said. You can buy the combustion checker at napa auto parts.

Hope this helps

Don

[Chris 85 RTS]

I have been battling this same problem on my RTS.  Did you know that per spec a 180 degree stat is not fully open until 198 degrees?  My bus will show 180 degrees at idle or in sub 50 degree weather (rare here in FL).   As the outside temp goes up, so the the running temp.  In 90+ weather it will run up to 200 within 10 miles on the highway running near the govenor (55-60mph).  Any additional load will cause a very slow creep above 200, then it will  not cool back down unless I slow down to below 50 mph.   170 degree stats should allow the motor to run at 190 instead of 200.   However, I suspect the temps would still creep up to above 200.

I have had my radiator cleaned inside and out, new coolant at 50-50, fan is belt driven, airdams in place, I never loose any coolant, I have tried the V731 tranny mod for clutch drag.  All with little to no effect.  My engine is a 6V92TA EPA spec. 

Things left to try:  30-70 coolant to water ratio or straight water (as a test only), new fan to move more air, new radiator (more rows), new gears (drops engine speed, coolant moves slower through radiator), external tranny cooler (V730 runs hot).

[TomC]

Not cooling down until you lower your speed to 50 tells me you have an air induction problem.  Maybe try a scoop mounted vertically in the middle of the grill.  Then the front part will pull in air and the area behind will be a vacuum that will also pull the air into the radiator.  Good Luck, TomC

[rdbishop]

Busnut 83,

I had the same problems with my MC-7 for years. Finally someone asked me if I had changed my muffler to turbo. I put the new muffler and problem was gone. I can now run 70 all day long with temps about 195.

Good Luck,

Richard