S-10 runs hot

[82 Auto]

I have a 1992 4.3 4x4 S-10, she was running hot& 25psi pressure in the radiator. I removed heads 1 was warped, had them sufaced,rebuilt & checked for cracks, after assembling with new gaskets, water pump, radiator & thermastat pressure is now 16 psi . truck will idle all day and driving 55 will stay 190 degrees, but as soon as you reach 70 on the open road it goes to 210 & occationally 225 degres . I have changed temp sending unit and installed manual gauge. Whats up

[eti engineer]

What degree t-stat did you install??

When I beefed up my 4.3 I had to go to a 160 degree stat to keep it cool, but then I live in Calif., too.

Any possibility of blockage like a rag left anywhere?? I have seen worse..

Later..

eti engineer

[82 Auto]

The engine called for a 190 themostat, I replaced it again thinking maybe the 1st one was defective,same thing again another mech told me to drill a 3/16 hole in it same thing again. Knowing I had a temp problem I was very carefull too inspect block & water passages all looked good. When driving and it reaches 210 -230 you can back off the gas to 55 and it will drop to 190 almost instantly, the temp redlines at 260 but has never reached that hot. I have also had the cat converter checked & was told it was working properly. thanks for any info.

[ff89lx]

on my 2nd 94 with the 3rd engine for this one. now. shows it is running hot but snapon scanner shows computer only reads 185 guage reads 230. was told to check timing but marks on my pointer are not readable. was also told to look for vacuum leaks, need another cpi for my 93 if anyone has one around northern ohio.( i would be happy with any long as it as the balance shaft.

[sector95]

I had a '91, 4.3L w/2wd, bought it new, and it ran hot from day one. It was okay when the A/C was not on; coolant temp would run about 190-210deg on the dash gauge. In summer driving w/the A/C on, coolant temp would run 210 upwards of 220. My solution was to install a 160deg t-stat....and it fixed the problem....coolant would run 180-190 and just peak at 210 w/the A/C operating. The lower temp t-stat allows the coolant to begin flowing through the radiator sooner.... sort of getting a head start on dissipating heat. I think the 160 t-stat is what is needed because the stock radiator (IMHO) does not have the cooling capacity to effectively shed the additional heat load when the 190deg t-stat is used...especially under high engine load/temp conditions.

IMHO, the radiator on these 4.3L engines is not big enough to provide a reserve cooling capacity (such as when the A/C is on in the summer or your doing high speed freeway driving). I have a '00 Jeep Cherokee w/the 4.0L I-6 and these engines have always run hot....the radiator Chrylser uses on them is barely adequate for the task at hand.


mike

[eti engineer]

Late on a reply, but I have been busy..

From what you are saying, it sounds like it could be your radiator. I have to flush mine often as well as having to spray out the fins with hi-pressure water to keep things cool. Like sector 95 said, the radiator on the S-10 is marginal at best.

If worse comes to worse, you could install a pusher fan on the radiator, but I would only do this as a last resort in that your truck seemed to have run ok until recently.

Any chance of a compression leak into the cooling system (head gasket)? Sometimes when this happens, you can pull your radiator cap, run the engine until warm and see if you get compression leakage into the cooling system. It will bubble your coolant if this is the cause.

Later....


eti engineer

[OverBoardProject]

Have you checked the fan clutch?

And if you have air conditioning make sure that you seperate the 2 rads and clean between them. I've seen this cause problems more than once including on my own car.

[Bads Crew]

Originally Posted by OverBoardProject

Have you checked the fan clutch?

And if you have air conditioning make sure that you seperate the 2 rads and clean between them. I've seen this cause problems more than once including on my own car.

Yeah......What he said. ^^^^^^^^^^

[tdarty7]

i talked to a radiator repairman he said when a chevy s 10 get around 100000 miles the radiator need rodded out or replaced
i had over heating, my gage went up to 230 or so i replaced it and water pump and 180 thermostate i does not run past 160 to 180 any more the cooler you run it the better, i put and electric fan on it . it cuts on at 210 to 215 and brings it down to 170 180 i took off the fan blade . it has more power also
you add about 15 horses to it ,add a low flow air filter, poweradder or k and w air filter for 10 to 12 more horses.

[Blue Bowtie]

When driving and it reaches 210 -230 you can back off the gas to 55 and it will drop to 190 almost instantly...

Check the lower radiator hose ot make sure it isn't collapsing under the pump suction at higher RPM.

[blazes9395]

Originally Posted by Blue Bowtie

Check the lower radiator hose ot make sure it isn't collapsing under the pump suction at higher RPM.

This is exactly what I was thinking....

Also, was the timing checked/adjusted when you put everything back together?