Fan clutch questions/Problem

[Ford4life32]

About a year and a half ago i would hear the fan clutch kick on from time to time when things got a little warm. Which now i know was normal for our 4.0s but one day i decided to race my buddy while it was on (young and stupid) and ever since then it never kicks on. A few months after that is when i really got into my explorer, started to customize and treat her like a baby. But last summer here in MI it got pretty hot and was sitting in a drive through line with A/C on and i wasn't paying attention to my dash and i heard a pop and looked up and smoke was coming from my hood looked down and my temp gauge was all the way up. Shut her off and rolled her to a parking spot turns out the overflow reservoir cap popped off and in it was boiling coolant. I let her cool off and she drove fine as long as the A/C was off. Couple weeks later was sitting in it with A/C on and i noticed my temp gauge moving up so i shut her off. It happened again when i drove down to florida in stop and go traffic started to overheat and when i was trail riding with no A/C on. The one mechanic i go to doesn't want to replace it because he doesn't know for sure if thats causing the overheating problem. The thermostat housing was replaced 8 months ago with thermostat and the coolant was flushed so i would think it has to be than fan clutch. Should i get an aftermarket fan and install it or just replace it with the original? Any help would be greatly appreciated.

 

[Flag Gibby]

Based on what you are saying, I personally would start with a new radiator cap since the only thing that I can think that would cause an overflow reservoir cap to pop off is if the system is way too pressurized when it finally opens. Then go from there if it still persists, but there are ways to test the fan to see if it is turning on correctly etc. before replacing it.

 

[BrooklynBay]

What was the temperature range of the new thermostat? Did you use a fail safe with a bleeder hole?

 

[Flag Gibby]

On another note, there have been individuals here that have reported issues with the water pump impeller coming loose resulting in poor system circulation.

 

[Ford4life32]

Based on what you are saying, I personally would start with a new radiator cap since the only thing that I can think that would cause an overflow reservoir cap to pop off is if the system is way too pressurized when it finally opens. Then go from there if it still persists, but there are ways to test the fan to see if it is turning on correctly etc. before replacing it.

I will get a new cap just as a start and i will have to check out the ways to test of the fan kicks on.

What was the temperature range of the new thermostat? Did you use a fail safe with a bleeder hole?

I cant recall, maybe i should just replace it just to be safe. But that still doesn't explain why the fan doesn't kick on like it should

 

[MotorCityFats13]

failsafe t-stats break once you overheat this is what causes the failsafe part... when it cools down it just stays open so it would act like a bad "open" t-stat...if mine ever goes bad Im just going to replace it with an electric fan... ive done this with every car/truck I have owned when ever a clutch goes bad since I have a horrible track record of removing the clutch with out snapping it off the neck....

 

[Ford4life32]

failsafe t-stats break once you overheat this is what causes the failsafe part... when it cools down it just stays open so it would act like a bad "open" t-stat...if mine ever goes bad Im just going to replace it with an electric fan... ive done this with every car/truck I have owned when ever a clutch goes bad since I have a horrible track record of removing the clutch with out snapping it off the neck....

Is it a difficult thing to do? because I am really considering doing just that

 

[Flag Gibby]

Converting to an electric fan setup is not terribly difficult, but you can easily spend a lot more than it costs to just replace the electronic viscous clutch assembly (easier to replace the clutch than a full electric conversion in my mind). As far as you having a fail safe t-stat, it doesn't sound like it to me since it sounds like the vehicle continues to overheat in situations and a stuck open t-stat would make the vehicle very difficult, if not impossible, to get up to operating temperature especially in Michigan in the winter. Also, since you have had this ongoing issue for quite some time it is hard to tell from your post if the vehicle is still overheating after having the t-stat replaced and if you hear the fan change speeds when it gets up to operating temperature and you turn the AC on.

 

[Ford4life32]

Converting to an electric fan setup is not terribly difficult, but you can easily spend a lot more than it costs to just replace the electronic viscous clutch assembly (easier to replace the clutch than a full electric conversion in my mind). As far as you having a fail safe t-stat, it doesn't sound like it to me since it sounds like the vehicle continues to overheat in situations and a stuck open t-stat would make the vehicle very difficult, if not impossible, to get up to operating temperature especially in Michigan in the winter. Also, since you have had this ongoing issue for quite some time it is hard to tell from your post if the vehicle is still overheating after having the t-stat replaced and if you hear the fan change speeds when it gets up to operating temperature and you turn the AC on.

Well the thermostat housing and tstat were replaced only because the thermostat housing went on me and im pretty sure those were replaced before it started to over heat, but the thing is i never hear the fan kick on anymore with the A/C on or anything. I know that it did when i first got the truck i could definitely hear it.

 

[Flag Gibby]

If it is overheating in the winter of Michigan after everything was replaced then I would say that you have a defective t-stat that is stuck closed. As far as never hearing the fan kick on anymore even at startup sometimes then I would check the power going to the electro-viscous fan clutch and verify that it even has power going to it. Then, like mentioned before, test the clutch. See here: http://gmtnation.com/forums/topic/12497-how-to-test-the-electro-viscous-fan-clutch/