Mep 802A temp question

[justacitizen]

i have been fooling around some with my 802A with 4400 hours. when i start it and run it for about 8 to 10 minutes with no load the coolent temp will read about 140 with ambient temp about 70 degrees F. oil temp is about 100 and both exhaust ports checked with a laser thermometer are real close to same. i confirmed the temp with the laser. do i need to wait until i can put a decent load on it?

 

[DieselAddict]

No, it should come up to temp without a load. If it stops at 140 and you know that is a good reading you should check and see if you have heat going into the radiator. If you have heat the thermostat needs replacing.

 

[justacitizen]

that's what i thought. i am getting good flow so probably doesn't have a thermostat installed. anyone know a stant number or some other crossover so i can just go to the parts store and get one? what temp thermostat should i get?

Thanks

 

[Zed254]

My notes say..... Thermostat – Murray Ultra MU55358 ('69 Chevelle SS 396 4bbl), Gasket – CST-2138 (2 Inventory)... Stant 45358, Gasket 25138. Gates 33008S, Gasket Gates 33624 these from cross ref chart.....ACDELCO 12TP1D, MOTORAD 2000180 these from Rockauto. These are 180F.

 

[Farmitall]

that's what i thought. i am getting good flow so probably doesn't have a thermostat installed. anyone know a stant number or some other crossover so i can just go to the parts store and get one? what temp thermostat should i get?

Thanks

Had same issue with my 803a. Wouldn't come up past 130 degrees after 1 hour.

A Diesel engine will run at minimum temperature for a very long time with no thermostat or a stat that is stuck open.

Installed the Murray Mu55358 and gasket # 2138. Now runs at 180 degrees which is good for summer operations.

Oreilly's Auto Parts had them both in stock.

I buffed the housing clean and use a very light coating of Indian Head gasket shellac on both sides of the gasket to insure a good seal.

Your upper hose should be noticeably hotter than the lower hose.

Prior to installing the thermostat, both hoses were equally just warm......that indicates either a stuck OPEN thermostat, or a missing thermostat. Mine was missing.

 

[justacitizen]

Thank You Zed for the part numbers. it seems that a missing of dysfunctional thermostat is common on these. i think i will order a couple and keep a spare.

 

[Farmitall]

Thank You Zed for the part numbers. it seems that a missing of dysfunctional thermostat is common on these. i think i will order a couple and keep a spare.

If these sets were used in a very hot desert environment where daytime temps reach 120+ degrees F, it's likely the thermostats were removed to bring the temps down.

Good idea on keeping spares in stock, that's what I did, they are cheap.

Also, you can use a very thin coating of that gasket shellac on the inside of the hoses, it helps them slip on easier and seals well.

 

[justacitizen]

Thanks Farmitall
the old girl has 4400 hours so it has been used but it was never repainted to desert camo so who knows. but it definitely has been a prime power for something.

 

[maniatopoulosg]

Had same issue with my 803a. Wouldn't come up past 130 degrees after 1 hour.

A Diesel engine will run at minimum temperature for a very long time with no thermostat or a stat that is stuck open.

Installed the Murray Mu55358 and gasket # 2138. Now runs at 180 degrees which is good for summer operations.

Oreilly's Auto Parts had them both in stock.

I buffed the housing clean and use a very light coating of Indian Head gasket shellac on both sides of the gasket to insure a good seal.

Your upper hose should be noticeably hotter than the lower hose.

Prior to installing the thermostat, both hoses were equally just warm......that indicates either a stuck OPEN thermostat, or a missing thermostat. Mine was missing.

Question though if the unit is operating in
hot conditions above 100° would it be better for them not to be a thermostat? Or we need to thermostat for pressure regulation?


Sent from my iPhone using Tapatalk

 

[Guyfang]

No. If it was better to run it without a thermostat, then there would not be one in it. Don't fool with something that works.

 

[Light in the Dark]

The thermostat helps to regulate the block temperature, which is a factor in the combustion process.

 

[Farmitall]

The thermostat helps to regulate the block temperature, which is a factor in the combustion process.

Yes, and it gives the coolant in the radiator some time to lose heat before returning to the engine.

 

[Farmitall]

Question though if the unit is operating in
hot conditions above 100° would it be better for them not to be a thermostat? Or we need to thermostat for pressure regulation?


Sent from my iPhone using Tapatalk

No pressure regulation involved, it is temperature regulation that is in play. The pressure in a cooling system is just a result of the coolant heating and expanding.

The coolant needs time to lose heat as it passes through the radiator and the engine needs time for coolant to come up to operating temperature by putting a thermostat in the path of flow.