Engine overheating - summer problem?

grisher

Thanks for your comments. Surface of radiator and space between a-c grill and radiator appear clean. Regarding serpentine belt issue, the charge indicator stays on and unchanged when a-c and lights both are on. When engine is running and at normal temp, the radiator hoses are not sucked flat, (but) they give to the touch (I thought with system being pressurized, they'd be harder to compress with my fingers).

fleetwoodsimca

The difficult nature of diagnosing this problem may be why the vehicle was put into the used market by the former owner.

swschrad

there is likely one or two problems at the root of this, they just haven't been attacked yet.

yes, hot hoses will be a little soft. that's why there are big-pitch springs inside them, to keep them from going flat on you if they get hot.

it's not impossible there could still be a thermostat that won't open, or was put in backwards, and the way to insure you don't have that issue is to take it out and put the system back together without it. the engine won't hit its warmup points correctly and will be off the computer program, but what the hell, it probably won't die from it, just waste gas and maybe be logy at worst while testing.

if the engine still gets hot and the radiator does also, the water pump is working. if the radiator gets sorta hot, it's probably almost plugged, and needs to be rodded or replaced. if you can't get it out of the normal range, you found the problem. if the stat tests OK, it might be the water pump, not sure what a good functional pressure-type test of one is, I've done my few replacements when the bearing starts to leak.

I should probably mention that if there is any orange coolant in there, you have no fun coming. the orange Dex-Cool stuff does NOT mix with anything else, and if somebody tries, you get orange cement-like crud plugging things up in the cooling spaces. somebody who has dealt with it successfully would have to try and chemically flush the stuff out to save the engine. I found that evil in my sister's system, and had to replace the overflow hose, but by some miracle the radiator was not badly munged up, and a dealer flush cleared it up. it also doesn't like air, same result.

fleetwoodsimca

My experience has been the same. The bearing weep hole lets coolant run out enough to get your attention to the loss, and you change the water pump. Are all the late model pumps still sporting the bearing hole? I have had several radiators cleaned and rodded over the years, having a good friend in the business.
AND thanks for the info on what really happens when orange meets green or yellow. I have asked several car people about it, and have never heard a definitive word until now. Why did GM get into something that potentially problematic?

grisher

Think I'm gonna take it to the mechanic who always worked on my ex-car, an Altima, and my wife's van. He'd test all the options, but said he suspects the radiator. It has overheated only when the a-c was running in very hot Memphis weather. As long as I leave a-c off, it stays in bottom third of normal zone. Mechanic wondered if broker who sold me truck might have overcharged a-c system with refrigerant, which he said would make the a-c condenser get super-hot and affect overall engine heat. I tend to doubt this, because previous owner was obviously having overheating problems, based on entries in maintenance booklet. The other thing that I haven't mentioned is that the automatic transmission sometimes shifts erratically, and that also happens when the engine temp is on the higher side of the dial. Since AT fluid passes through a cooling thingie in my radiator, I wonder if the two situations are related. I am leaning toward a new radiator as a catch-all solution, but I don't have enough confidence in my mechanical abilities to do it myself. Also, I would like to put a heavier duty radiator in, because I got the truck to pull a horse trailer eventually. I think my factory radiator is a one-row. Looks kind of puny for a truck that size.

fleetwoodsimca

I couldn't agree more on the heavy duty radiator for pulling a loaded horse trailer! Please be sure to let us know what the true diagnosis turns out to be.

swschrad

about time for a fluid and filter change on that tranny if there is any suspicion of abuse, and overhot sure meets that description. and yes, if you have/can get the brackets to hold the biggest radiator spec'ed for that vehicle, put it in, and upgrade the tranny and a/c heat exchangers if you really plan to tow.

amazing there are radiators that have enough metal to be roddded out any more, most of them are so thin that a few years of aluminum/salt corrosion on roads like Minnesota's will rot through. the old days of brass radiator cores that could be reamed free of rust and verdigris and silver-soldered or brazed where the push rod broke through are gone, folks.

of course, it all ends up as cost at some point, and since cars are so beastly expensive compared to the simple runabouts when we were kids, the non-core parts get cheaped out to a 3-year design life or thereabouts.

grisher

Mechanic installed four-row brass radiator and temperature needle hasn't risen past the o in normal since, with a-c blasting. Mechanic said looked like truck had been in fender-bender and a previous owner had installed a too-small one-row aluminum and plastic job. Transmission, it seems, was unrelated. Transmission shop did drain and flush and installed new range sensor.

swschrad

yeah, sounds like it was a fix it fast and sell it before anybody notices it job if he did that on the front. for the natural randy halibut, you ought to have a body shop guy check the front end next time you fall over a wad of cash on the sidewalk. there might be exitements up there you would want to know about.

on the other hand, it could be that all that was hosed up was the radiator and some fancy plastic. but my sister bought a "cheap cheat job", as diagnosed by the dealer who sold it, because it had not been adequately qualified before it went on the lot. first road blow it hit, the thing would have disintegrated. took it back for a look-see because the hood never closed right, and the body shop guys put a boot on the car and called the sales manager saying this was a total, and they needed to do a make-good.