This one has me stumped....


1995 S-10 4.3L and its overheating. We have flushed the system, replaced the thermostat, radiator, fan clutch and the hoses. The truck still gets above 220-230 on a overcast 90 deg. day.

His business is yard working and he hauls around a trailer most of the time.


Any suggestions on what to do?

(please no smart arse replies)
Dan

Have you checked the water pump? My dad has a 96 with the 4.3 and the water pump went out and he didn't know it for a few weeks. The temp would get up to 210 and he would check the water, fill it, and look for leaks, none to be found. It was leaking so slowly that it was either burning off or blowing off when he drove it.
After a few weeks of this we tore it down just to look around and found the bottom of the pump wet. Replaced it, no more problem. Strangest thing I have ever seen. Usually when one goes it just pumps the water out.

radiator might be clogged, just because it was flushed doesn't mean a whole lot.

any evidence of a blown head gasket ???

does it overheat w/out a trailer? or all the time?

Slam a sbc in it and be done:thumbsup:
check the Rad. like old shifty said:yes:


EDIT ooops you replaced the radiator are you loosing water anywere?

whats the oil look like? (check under the fill cap for milk pudding)

I'd also grab hold of the fan and wiggle it. If it moves the seal and bearing in the pump are gone. It doesn't have to actually leak to cause a problem because as the impeller moves away from the backing plate it stops pumping water it just adds heat to the already hot water by stirring it. Replace it with a high volume aftermarket water pump that has an enclosed water pump impeller, bigger shaft and larger bearings.

Big Dave

(please no smart arse replies)
Dan

Well what fun is that Dan??? geez I second or third the water pump, I have even seen the impellors eaten away and they just don’t pump enough volume to cool (but still don’t leak). If that doesn’t work let it roll down the boat ramp at Breton Bay…opps!:thumbsup::D

Thanks for the replies guys....

The truck overheats when he is either trailering the mowers or his small pop-up camper. There was one time that he wasn't towing anything and it overheated, ( with the A/C on )
When we flushed the fluid last week, ( before replacing the radiator ), it showed no signs of looking like an expresso. The oil is not showing any signs as well. I am thinking a cracked head gasket that is putting hot air into the radiator but, I see no signs of white smoke out the back.

It looks like the friggin water pump is the consensus here and by all means, if there is something else please let me know...


Mike..... I get jokes. That is the 1st thing I thought of doing myself but, its a Chevy. Now if it was a furd, then, I would deep six it and let it become a sandbar in the middle of the river...

The postive is that taking the rad. shroud and the lower hose off are the hardest part of the job. Tip: Take the lower rad. hose loose of the Rad. and install it on the new pump before installing the pump. Almost impossible to get to the clamp on the waterpump with it on the car, I found out the hard way.:D

Steve... thanks for the tidbit!!!