WHY is this engine overheating?(truck, not tractor)

[Stimw]

I had a 1989 Chevy 1500 that I changed from 4.3, 5 speed to 5.7. auto. The 6 cyl radiator is smaller. When installing the V-8 radiator there is 1 or 2 (I can't remember) side plates that have to be removed for the V-8 to fit.
Are you sure you put the thermostat in corectly? The round copper pellet goes toward the engine.

 

[638]

220 is not too hot with a 14 lb pressure cap.

ron

 

[woodchuckie]

I had the same engine in a 92 Roadmaster that had been through hurricane Fredrick and covered in salt water. The front part of the radiator covered by the evaporator and impossible to inspect turned out to be my problem. Radiator had to be removed to see it. The alluminum fins were coroded .

 

[gemini5362]

Try this just to see what happens. With the thermostat in when it starts getting warm tun on the heater with the temp control to the hottest position and the fan on high. See if the engine starts cooling down. If it does cool down more then start looking at another radiator. I have found that sometimes you can get a new or rebuilt radiator at a parts store for not much more than having one recored. In your case where you are not sure if it is a big enough radiator I might just look into getting one at autozone or somewhere like that.

 

[RobJ]

220 is not too hot with a 14 lb pressure cap.

ron

I think it is, with a 190 thermostat the engine should remain at that temp.

I would replace with another new thermostat, but try a 180, and make sure it's not obstructed in any way(and it's the correct one). Check to make sure you are getting coolant flow when it opens. Sounds like you are getting flow when the thermostat is out. I'm not sure in this one but make sure you don't have to bleed the system of air. On my sons 97 mustang (v6), there is a bleeder screw on top of the thermostat. I think that sits higher than the radaitor.

Good Luck,
Rob

 

[Soundguy]

Try a flow test.. with bottom hose off.. put a garden hose inthe neck and see what it will flow..

Soundguy

 

[ovrszd]

220 is not too hot with a 14 lb pressure cap.

ron

I agree. Even with a 180 thermostat. My Jeep 6 cyl runs 210 unless it's very, very cold outside and it has a 180 thermostat. If this vehicle is not puking out coolant, it's fine.

 

[clundog]

Lots of good advise here so far! I had an 82 Chevy 1/2 T converted from V-6 to V-8. I had some overheating problems as well. It had the small 2 row radiator, so I put in a larger one and still had some problems when it the outside air temp was warm (summer time). The V-6 fan shroud wouldn't work with the V-8 so I didn't use one initially. After a trip to the salvage yard I picked up the correct fan shroud and this cured the problem.
Good Luck!

 

[RobJ]

I agree. Even with a 180 thermostat. My Jeep 6 cyl runs 210 unless it's very, very cold outside and it has a 180 thermostat. If this vehicle is not puking out coolant, it's fine.

the only way I would excuse 210 temps with a 180 thermostat is if I was idling in the summer with the air on full blast in 100+ degree temps, or putting some great load on it.

if you are just strolling down the road and running that much over there is a problem somewhere. the thermostat is designed to keep the engine at that temp, not hotter or cooler. my for or chevy can idle all day with the air on in the summer (in houston) and never move.

 

[john_bud]

There is one "oddball" thing that hasn't been mentioned.

The water pump could be the wrong one for the application. Some need to turn the oposite direction. Any time you deal with a swap situation that you didn't do, you need to think about the accessories on the engine working. Late model pullies could have been swapped onto an early model block.

Any chance the T-stat is in backward?

jb