Dont lose your cool . . . .

[Jcnbama]

I have a 94' Ford Exlporer 4x4 with right around 200k under the hood. She's a good running truck but lately I have been having some overheating issues. It over heats when I have to get on the gas a bit to go up a mountain and especially with the A/C on. It doesnt run hot when it idles, only when the RPMs are at 2500 - 3000 accelerating for long periods of time or the engine is under strain ( Max A/C ). I have changed the thermostat and flushed the sytem and the fan and belts are all in good working order. It boils over so its not a faulty temp hand its definetely HOT. Does anyone know of any other problems that might cause this? Blockage maybe in the radiator itself or perhaps the water pump, but then wouldnt it run hot all the time? hmm. . . THX for any help.

 

[mikeinri]

One other thing to consider is air flow, although usually that shows up when idling...

On my 94, I had leaking rubber hoses on the tranny cooler, which is behind the grille, in front of the A/C condensor, which is in front of the radiator. What happened was, I ignored the leak too long, and between the ATF and road grime (bugs, leaves, dirt, etc.), a nice thick layer developed on the entire front of the A/C condensor, which basically blocked the air flow through the system. The weird part was, it didn't overheat all the time, but was definitely worse when towing, running A/C, etc.

My advise is to pull your grille and take a look at the rubber lines, if they're wet, replace them. The fix is easy, all you need to do is replace those lines, and get some engine cleaner and a good nylon brush and hose to clean out the fins of the A/C condensor.

Hope this helps!

Mike

 

[msmith65]

What mikieinri said. When I bought my '93 I found lots of leaves and junk between my a) trans cooler and AC condenser, and b) AC condenser and radiator.

 

[Jcnbama]

Well I thought I had it fixed. I cleaned the radiator which was rather dirty and drove it around town, up hills etc. with Max a/c on and it was fine. Then in the evening it started to overheat again . . 2 questions. 1) what exactly would be the symptoms of a failing ater pump? and 2) when the thermostat on a 1994 Explorer XLT open should you actually see water "circulating" through the system or would it just drop a but and bubble. What would the symptoms of a radiator blockage be? THNX ! ! !

 

[vrytired]

it may be time for a new fan clutch with that many miles. i didn't realize how bad mine was until i replaced it.

 

[Jcnbama]

Well, I had thought of that, maybe the fan wasnt running fast enough to keep it cool but doing the " spin " test and just a general inspection of the assembly it seems okay. It moves alot of air when you fire it up and open the hood its running good. I think this is a coolant / lack of circulation problem.

 

[mikeinri]

Do a search for better details, but basically, a failing water pump will either drip coolant out of the weep hole, or make noise if the bearings are shot.

As for the radiator, you should definitely be able to see flow. If the radiator is original, you may have blocked passages. Not sure how common that is, I think it is more a function of how well the coolant has been maintained over the years.

If this were my truck at this point, I'd spend the money to have a radiator shop do a thorough diagnostic. You can do the work yourself to fix any problems and save some money that way, and you won't be wasting any more of your time trying to chase this.

Hope this helps.

Mike

 

[Tbars4]

a blockage in your radiator and/or your heater core will show up especially while under a load...if you have a piece of scale that lifts up and makes a partial blockage is all it takes...as also mentioned, the fan clutch...whenever i have run into the same problem i have taken my radiator to the radiator shop and had them rod out the radiator...while that was being done i would replace the heater core for about 20 bucks and replace any bad hoses at the same time...put it all together and you know you have a good system and if it happens again, take the fan clutch out and get the exact replacement...they all give them different names as in heavy duty etc. but be sure it looks just like yours...it sounds like alot of work and it really isn't and it's relatively cheap and a long term fix...compared to blowing a hose or a motor, it is the only way to go...i hope this helps...

 

[Jcnbama]

Well yesterday evening I finished my Prestone radiator cleaner project. Its' "supposedly" supposed to break loose any rust and scaled up deposits. I followed the directions and drove it for 3-4 hours over the course of a few days. Then Flushed and Flushed and Flushed some more. I'm sure the water pump is good, replaced the thermostat, and cleaned the fins. The only thing left is the radiator cap and the radiator itself. I've got a trip to Georgia ( 3 hours ) this weekend and if it runs a little on the " High " side I'm takin Mikeinri's advice and goin to the shop. . . sometimes its just not worth the time to chase it . . . Thanks alot guys ! ! !