Overheating still...

[TYSHO]

For some reason my 93 ATX likes to get really hot when the a/c is on full blast. It will go all of the way up to the last line before entering the red, then I shut it off to prevent the overheating. If everything is turned off [headlights, radio, and a/c], it will run fine.

So far, I have replaced the radiator cap, t-stat, ECT sensor, and flushed the system out completely and once with the Prestone coolant flush. The water was coming out crystal clear.

Any other reasons or causes?

The only thing I can think of is the radiator fins, but when I looked through the condensor, I could see through it and the radiator, making a view of the exhaust manifold shield. If it was clogged up, that wouldn't be possible, right?

The fan kicks on with the a/c and all, too.

This one really has me thinking! So much that I am beginning to wonder if the Coolant Temp Sensor for the gauge/cluster is a little faulty giving false signals/readings, while everything is truly fine and is why little load shows big needle jumps.

Anyone?

 

[voogru]

put your hand on the radiator or use a temp gun and try to feel the radiator core for any cool spots, may have clogged radiator, I know its tough to get to but not imposssible, make sure the cooling fan is working, it could work and not be spinning fast enough i/e electric motor on last leg.
Javier

 

[greenbeanmtx]

i wouldnt be suprised if the temp sensor is incorrect cuz the truck i just sold had the same exact problem and it was just fine. The guage had a mind of its own and turning the a/c on was like flipping a light switch. But i agree, feel for spots that arent hot and make sure there isnt air in the system.

 

[Red Devil]

1. What is your distilled water/antifreeze ratio (60/40 is best IMNSHO)?
2. Have you tried water wetter yet (Red Line makes it, others make similar products, but I've had best luck with this)?
3. What condition is your w/p belt?
4. Have you verified fan functionality yet?

Just recontextualize #3 then answer the questions.

 

[TYSHO]

Well I am about to head out for the day, so I'll get back on this, but I never use that much coolant. 15-20% is good enough to keep lower temps as the only purpose of coolant is to raise the boil over temp.

Fan works, but I need to check out how fast now.

As soon as I can find my basically new sensor that was removed for gauges, I will put it in and see if that helps.

As for the radiator being clogged, I don't think so because I flushed the whole system and did that back flush crap they talk about with the kit and what not. There wasn't any problems or inconsistant exiting of the water.