OK. We've narrowed down that it is NOT the e-fan. So this basically makes no sense now. The AC Condenser is in front of the radiator so even if the engine is overheating, the AC should still continue to work. weird.

Is there water in the coolant reservoir? If that tank is empty, you are low. With the engine cold, fill up the radiator and fill the reserve tank up 1/2 way. See if it gets sucked down again when drive next and add more to the reserve tank. You could just have a low coolant condition.

 

Totally WRONG!!! The PCM will shut the AC compressor off with an overheating condition, by picking the WOT relay. In addition to that,
if the AC condenser doesn't get cooled properly, that keeps the AC from working properly.
He needs to get rid of that POS E-fan!!!!

 

Smart guy, I said several times that inadequate air flow over the condenser would stop the AC from working. Thanks.

The overheating causing the PCM to shut off the AC via the WOT relay is news to me. Good to know. Doesn't change the fact that the fan is working and something else is wrong.

 

BINGO!!!!!!!!!!!!!!!!!!!!

 

I've had an e-fan for over 2 years, and it just started the overheating ordeal less than a month ago. The e-fan works. We will see in the near future whether it was the thermostat or not, since I replaced it yesterday.

Quote from 6over_a_armed_ranger on dezertrangers.com:

"its not a thermo.... this is simple. dont use the radiator flush from the store. pull the radiator spend the 60 bucks and get it flushed.

i went through 900 bucks 15 thermos new water pump flushed my system 20 times new water pump new timing chain 5 diffrant fan set ups. the part that was weird was it was over heating random. went from stock fan and 14 inch e fan puller to stock fan and 16 inch efan puller to 16 inch efan and 14 inch efan puller. once i had it cleaned out my 14 inch puller was enough to keep it cool setting in traffic for 30 mins dead stop 103 degree weather. out mobing it 2 hrs of non stop ide finally hit my puller fan around 200 degrees and in seconds it whould drop to 185.

when the radiator shop took the tanks off my radiator he told me all but 5 of the rows were blocked off. and it happend all of a sudden."

 

could be the case. But then why is your AC turning off. Is that clogged as well?

 

Apparently as previous mentioned by others, the A/C is controlled to shut off if the engine gets too hot. The A/C will not work well if it is too hot either. The overheating of the engine and engine bay and radiator would result in the A/C not being to cool down either thus making it not work properly.

 

still does it, oh boy...

 

interesting. I think I need to have that done. thanks!

 

I replaced the thermo 2 days ago, and it overheated again last night. I literally felt the cooling hoses going in and out of the radiator and they were hot, so i'm guessing the thermo works and so does the water pump. The fan does work. What's next, clogged radiator?
The weird thing is that it overheated on my way home from the store, Rudeman85 and I checked the problem out for a few min. Then I shut the truck off for about 10 min then started it again to see if it was going to overheat again, and it didn't, it stayed cool. So it still randomly overheats. Could there be an air bubble in the system? If so, what's the best way to get it out. My buddy with an EVO said to jack the front up and let it run for a min then take the rad cap off and a few bubbles may jump up. Give that a try?

 

the air in the system should leave within a matter of time. i dont see that being an issue.

what about the radiator cap? if the system cannot build pressure every time then the flow will not be as high which can cause over heating. So if the cap is not sealing well enough the pressure could be released into the resevor. just as idea.

 

I think you owe it to your engine at this point to put the mechanical fan back on and see what happens. I realize it's a PITA but you've tried the easy stuff already. (Pressure testing the cap is a good idea, as well).

While I'm sure you're being careful, you nevertheless cannot afford to have too many more overheating (or near overheating) sessions.

 

Very true. I did plan on putting the stock fan back on tonight.
How can I pressure test the cap?

 

The naturally aspirated cooling on our trucks is quite significant on it's own. As long as the truck is moving, with nothing else wrong, it will not overheat with the fan turned off. So it is unlikely that the fan has anything to do with this. Something else is seriously wrong if the engine is overheating while the vehicle is in forward motion.

Clogged up radiator? Low coolant? Failing water pump? Low pressure? These are all possibilities.

 

That's what i've been thinking too, it should cool enough moving at a decent speed, but it doesn't.
How can I check the pressure? The coolant level is fine, and has never gone down/lost any. How can I check the water pump? As I mentioned, I felt to see if all of the hoses were hot and they were as if water was going through them.

 

When I had to test mine, I rented a cooling system pressure tester/guage from Autozone. I had to specifically ask for the adapter that allows for the cap to be tested.

Here's a page that'll give you a visual of what I'm talking about:

http://shopping.yahoo.com/s:Automotive:4168-Brand=Stant

 

some failures of the water pump could be.
-broke fins
-bad bearing
-bad seal
you can check for bad bearing or seal by checking the seep hole on the bottom side of the water pump. like in the picture below

i would just get a new radiator cap at 15$, but you can rent a tester at autozone.

also I was told if you overheat frequently it could be from a blown head gasket.

 

What are the symptoms of a blown head gasket? I'm not losing any coolant, and wouldn't that happen?

 

yeah loss of fluid and maybe poor running, excess moisture in the exhaust...

 

His truck is so weird, he shut the engine off and let the e-fan run for about 5 mins and started it back up. Temp. was normal again while it was at idle, I don't see how this can happen in any situtation. Especially when the engine is sitting with no air movement with nothing other then the fan.

confusing...

 

That means his fan is working it was able to cool the coolant in the radiator. Then when he restarted it he started it with cooled coolant.

 

But I let it idle for about 10 min and periodically holding the accelerator at 2k rpms. The temp did not overheat as it did a few minutes earlier. The cooling system was definately working at that time.

 

maybe something is wrong with the sensor?

if the CEL was on have it checked to see what it was

 

Nope, no CEL. The engine does get overheated, it's not just the gauge reading faulty.

When I get home from work today i'm going to try to burp some bubbles out of the radiator. Hopefully some do come out and fix the problem.
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