Overheat A/C on fan Clutch?

[jreece04]

Hello, I have a 1992 2wd x with 205K miles, I bought the explorer about 2 years ago with the A/C not working, About a year ago I replaced the entire A/C system replaced including the fan clutch and fan. Now if I run the A/C for more then about 20 min The temp gauge will start to climb. it gets to just below the red line and the car starts running like crap but has never overheated. When I turn off the A/C it will slowly go back down to between N and O or "NORMAL" I replaced the Thermostat about 5 months ago and i believe it is working because I can watch it heat up then drop back down during driving without A/C. this problem was not a big deal but now that it is summer time in AZ it gets above 100F everyday. I now am noticing it heating up with A/C off when under a load (going into the mountians)

in the last 4 months I have replaced the radiator hoses, cap (16lbs) and like I said just 5 months ago I replaced the TStat.

Also, The fan cracked within a month or so of being replaced and I returned it and had another put on and now it is cracked.

Could this be fan clutch, water pump, radiator? Any help would be great, these parts are not cheep so I don't really want to replace if not needed.

Thanks

 

[MrShorty]

Could be a bad fan clutch. For a case like this, the best test for a fan clutch that I've found goes like:

1) Remove fan clutch
2) Disengage outer end of bimetallic spring from notch. Rotate spring 1/4 turn CCW
3) Reinstall fan clutch and test drive. If overheating condition is resolved, then fan clutch is faulty. If overheating condition still exists, then fan clutch is not likely the problem.

Rotating the spring disables the fan's ability to "freewheel" so the fan is always spinning. When you get your ear tuned to it, you may also be able to hear a difference in the way the engine sounds when the fan is "engaged" and "disengaged".

 

[BrooklynBay]

Was your fan wobbling around when it cracked? Maybe the bolts weren't made tight enough, or the bearing on the water pump could be bad. Have you tried to flush out your radiator? If cleaning chemicals, and water pressure from a garden hose don't work, then your radiator might be clogged, and will need to be replaced.

 

[PTBishop]

there's an easier way to test the fan clutch....with the engine running, hood open, go out and rev the engine at the throttle body....you should be able to feel the air that is being produced. if you feel no air, or little air from the fan, chances are the fan clutch is shot.

 

[jreece04]

thanks for the responses. When I changed the hoses I did put the garden hose in the fill neck and it flowed out of the lower neck pretty good. Did not seem to have any sort of clog. I let it run for about 2-3 min full pressure. I did not however use any chemical flushes. I think I will try the fan clutch trick to see if it is faluty. Is there an easy way to check the condition of the water pump bearing. according to the service records it has been over 120K miles since the water pump was changed.

Thanks

James

 

[93TwotoneXLT]

There is no need to take the fan clutch off of the vehicle. In the morning, go out and pop the hood before you start the truck. Once started, as stated before, go out and rev the engine to around 2000rpm using the throttle body. If the clutch is still good it will be engaged for awhile when the engine is cold. Not to sound like a smart ass here, but it will sound like someone has turned on a fan right next to you while the engine is running. If the clutch is bad then all you will hear is the engine running/revving. Hope this helps.

 

[jreece04]

Well, I finally got around to working on the X. I put a new radiator in it. (FYI radiatorbarn.com only $111.00 shipped.) I still have an really hot/overheating problem. I did listen for the fan clutch to kick in but to be honest I am a little hard of hearing and if it is subtle sound change I can't hear it. The fan is moving air and after I let it warm up I can push on the fan blade and it will move about an 8th of a turn (the next fan blade will come up. That seems to be a bit much for a locked fan clutch.)
I took it out on the freeway today, it still warmed up with the A/C on. Does the fan clutch have any effect at highway speeds (65-75) it did take a little longer to warm up then in the city where it only takes a few blocks.

any suggestions would be great. Also does anyone have any step by step instructions for the spring trick. I have read that you can do it with the fan clutch left on the vehicle others say you have to remove it which sounds like a PITA.

James

 

[Wormy]

jreece, I can fill your pain! I have a 94 explorer that had the black death disease last year. Since then we have replaced the condensor, compressor, manifold hose, orfice tube, accumulator / drier, basically everything but the evaporator has been changed. I had a leak from the radiator and have changed the radiator, fan and fan clutch, thermostat has been recently changed also. What happens to us is that the vehicle runs fine during driving or idling with out the AC. If we run the AC, drive 15 to 20 minutes and then set in drive thru at a resturant or bank, the engine temp rises high and then the pressure relief valve on the ac will vent. I am about out of options, even took it to two speciality shops and they say nothing is wrong. It has been in the 90's every day and my wife is getting over it!

What does your idle do? Our idle does not seem to step up even during over heat condition it never gets over 800 RPM.

 

[gijoecam]

OK, two things come to mind. The first, of course, is a stuck thermostat, or one that's not opening all the way. This could be caused by having it installed the wrong way (inside-out) or by not having the bleeder hole at the 12:00 position when you installed it. I also wouldn't rule out a bad thermostat just because it's only a few months old. When I used to sell auto parts (*back when your 92 was still new) we had more than a few t-stats that were no good out of the box.

The other thing that comes to mind is the radiator cap. If the cap vents too early and doesn't maintain pressure like it should, it'll cause the same types of symptoms.

Both are relatively simple and inexpensive things to try.

Good luck!

-Joe

 

[MrShorty]

Also does anyone have any step by step instructions for the spring trick. I have read that you can do it with the fan clutch left on the vehicle others say you have to remove it which sounds like a PITA.

I'm sure you can do it with the fan clutch in the vehicle IF you can get your hand in between the fan clutch and the radiator and manipulate the spring. It's been a while, so I don't remember how much room there is between the fan clutch and the radiator, and I've always preferred to just pull the fan clutch out.

Here are the instructions I posted above

1) Remove fan clutch
2) Disengage outer end of bimetallic spring from notch. Rotate spring 1/4 turn CCW
3) Reinstall fan clutch and test drive. If overheating condition is resolved, then fan clutch is faulty. If overheating condition still exists, then fan clutch is not likely the problem.

What part do you want more detail on? Or do you just need to see a picture of the spring so you can visualize what you are trying to do (there was a recent thread where several pictures of fan clutches were posted)?

 

[jreece04]

Sorry for the long awaited response. I would like a pic of spring on the clutch, more so that I know what I am touching when I reach down there. The tstat works I tested it in a pot of boiling water before I put it in the car, and I can watch it heat up - open - then cool down on the dash gauge. The radiator cap is brand new, the hoses are brand new, I have a heavy duty fan clutch and new fan on the way, so we will see.

 

[ma96782]

My STOCK answer on over heating problems: (beside changing a radiator or water pump)

If you got the tools or access to the kit........pressure check the system.

While running and with the engine is off, make a visual check of the hoses for a hole, check for leaks at the connections. If it passed the pressure test, you should be OK. But, still check for a, "too soft" hose, which may collapse.
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Replace radiator cap........IF, you can't remember when it was last done........or if it's been more than a couple years since it was last changed. If it passed the pressure test, you should be OK.
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Fan Clutch...............when cold (engine off) try spinning the fan....it should spin freely or with very little resistance. If it won't spin.....replace.

When hot (engine off) try spinning the fan........in some cases it will feel like it's, "locked up," or it will be like there is syrup/glue holding it back. Tougher to spin, than when it was cold. If so, It's OK. If, it spins like a top.....replace.
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The below elec. tests are the, "cheap test methods"........there are more sophisticated tests with values, that can be run.

Test for the dash thermo gauge................disconnect the wire from the temp sender unit.........KOEO...........ground that wire.........it will peg the gauge on the hot side............disconnect from ground and it will return.

Sender unit.........if you suspect it..........replace, replacement is cheap.

Aloha, Mark