Running hot, AC cuts off

[Trigggl]

My 97 Rodeo has been running hot and in the summer I get half way home from work when it causes my AC to shut off. It's in the mid 90s here in Arkansas and I want to keep my car and myself cool.

I didn't think it would be the thermostat, but I just changed it anyways. No effect. It seems to have been running hot since before I changed the water pump. The previous water pump was leaking coolant out. I'd hate to do the work of changing the water pump again if that wasn't the problem, but I'm wondering if the Autozone special is working like it should.

What could be causing my engine to run hot if I have a good thermostat, water pump and new (relatively) fan clutch?

[Cat Fuzz]

The radiator could be plugged up.

[boritz]

...or...

maybe the system is not holding pressure. It only takes a pin-prick leak or a bad radiator cap.

Just another avenue to consider

[Trigggl]

Well, I checked the upper and lower hoses and they both get hot immediately once the engine is warmed up. I doubt it's a clog. The system is very clean and there's no loss of coolant.

[Ramblin Fever]

Triggle....are you the same member from Planetisuzoo?? The one that's getting ready to install a 2" lift?

I didn't realize your engine is a 2.6L...that alone is a lot of weight to haul around for that engine.

I don't know much about the 2.6L's, I have the 3.2L; but I can say if you've already replaced everything else, the only thing left to try is a new radiator OR it could be a headgasket failing issue too.

I know the 2.6L's tend to be a bit problematic.

Same thing happened to me in an older Toyota truck; radiator didn't look clogged, but it took the whole engine with it.

Also, I wouldn't be continuing to drive it or using the ac until the issue is resolved; if you have aluminum heads all it takes is one or two overheating conditions and your engine could be toast.

[mutley630]

Went down this road awhile back. Started out as temperature would only start creeping up and ultimately overheat with AC on (additional load.) Replaced Thermastat, water pump, flushed system, to no avail. Even started driving around in the summer with no AC (not fun.) Eventually, got worse and started doing the same thing, even with the AC not on.

At that point replaced the radiator and has been fine ever since.

Other thing to check (at least on my 3.2) if this only happens with the AC on is the electric fan. System uses the electric fan, when you turn the AC on to provide extra cooling. So, if the fan is not coming on when it should (they're notorius for getting "dead spots"), could work fine with the AC off and not so awful good with it on.

[Trigggl]

Originally Posted by Ramblin Fever

Triggle....are you the same member from Planetisuzoo?? The one that's getting ready to install a 2" lift?

I didn't realize your engine is a 2.6L...that alone is a lot of weight to haul around for that engine.

I don't know much about the 2.6L's, I have the 3.2L; but I can say if you've already replaced everything else, the only thing left to try is a new radiator OR it could be a headgasket failing issue too.

I know the 2.6L's tend to be a bit problematic.

Same thing happened to me in an older Toyota truck; radiator didn't look clogged, but it took the whole engine with it.

Also, I wouldn't be continuing to drive it or using the ac until the issue is resolved; if you have aluminum heads all it takes is one or two overheating conditions and your engine could be toast.

Yep, it's the one and the same. I may be needing to put the $60 towards this problem instead. I'm starting to get convinced that the cooling system is working properly, but that there is something else causing the engine to run hot in spite of it. When I start cold in the morning, I can see the temp rise quickly to where the thermostat opens. Then it levels out at the 180 degree mark. As I keep driving the engine heat eventually wins out and the temp starts going further up in spite of the cooling system. There are no leaks and I know the coolant is flowing.

I did a google search this morning to look up possible causes of an engine running hot and one thing that came up was a clogged catalytic converter. The symptoms sound about right. The truck has no power and I know it used to have more. My gas mileage is down for the past couple years. I used to get between 22-24, now I'm lucky to get 20. There are noticeable surges of power and then back to no power. This could be caused by back pressure.

It all sounds like a good excuse to get some performance pipes. I'll have the shop test it first.

[Ramblin Fever]

Cat would have to really be clogged.

Sounds more like overheat due to bad radiator; even if the coolant is flowing, doesn't mean there's not a blockage due to fins being old

[Trigggl]

Originally Posted by Ramblin Fever

Cat would have to really be clogged.

Sounds more like overheat due to bad radiator; even if the coolant is flowing, doesn't mean there's not a blockage due to fins being old

Took it to the shop. They said there is no sign of a cracked head, but that the radiator was the problem.

I guess I'll replace the radiator.

[Trigggl]

The radiator has been replaced. The truck stopped overheating and the air doesn't shut off. That's a good thing when it's 95 outside.