Lots and lots of problems....

[mmeister13]

So 2 weeks ago vacuum booster broke and had to get it replaced. Got that fixed and then noticed that the AC was turning on and off randomly after driving for about 10 minutes (usually got colder when I was accelerating and not stopped). I figured it was just the heat in the South. Finally last night after driving home I looked down at the temp gauge and saw the needle rising up to the red. Thankfully I was turning into the driveway when it went up so hopefully no serious damage. This morning I checked the fluid and saw it was a little low so I added some more hoping this would solve my problem..... but no. As I was pulling into work this morning the temp went back up into the red.

So without getting super deep into the guts of the car my high level diagnosis of the problem is:
1) The clutch fan is broken / or fluid is low which would explain why my AC is sometimes blowing cold when I drive and warm when I'm stopped
2) The thermostat is broke which is why the car gets hot

Does anyone agree with my diagnosis and/or have any suggestions?

 

[Frankencruiser]

Sorry, but overheating and low coolant is very likely a blown head gasket. The A/C will turn off as the coolant temp goes over 230 degrees IIRC, so it sounds like you have been running hot for a while.

 

[Stevesnj]

Have a compression test done to confirm a blown head gasket. If okay, have the typical items checked or replaced, i.e OEM Thermostat, blue hub clutch, hoses, radiator or radiator flush and leak tested, and heater valve and PHH hose check.

 

[ttubb]

Sounds like a headgasket. Go to Autozone and borrow/buy their block tester kit (about $35) which will test your coolant for gasses. Easiest way to confirm if it is a headgasket problem. Just follow the instructions. NAPA has a similar kit. Good luck and let us know what you find out. T

 

[mmeister13]

Nooooo!!!!!!!!

I was afraid of hearing that. I guess ill go home after work and do the block test and go from there.

I have been thinking about doing an engine swap for some time now. Is that something I should still keep in mind or just replace the gasket and machine the head if need be?

 

[NLXTACY]

Sorry, but overheating and low coolant is very likely a blown head gasket. The A/C will turn off as the coolant temp goes over 230 degrees IIRC, so it sounds like you have been running hot for a while.

Pretty sure it's 227 deg

 

[BrotherRob]

The clutch can cause the AC to cut in and out but not likely a serious over heat without additional issues.

Was the coolant low again after you got to work?
What was the nature of your drive? Stop and go or highway speeds?
Is any coolant hitting the ground or is there any sentiment around the fittings?


IMO, rule out the simple stuff before jumping to conclusions about the HG.

 

[Frankencruiser]

Pretty sure it's 227 deg

I see you have become the master of splitting hairs.

 

[Stevesnj]

T
IMO, rule out the simple stuff before jumping to conclusions about the HG.

...x2

I did this exact thing, did the Blue Water test and then a Compression test. turns out I had a bad fan clutch and radiator.

 

[mmeister13]

So as I said earlier I drive home after work and parked the car with the temp close to the red. Let it sit and checked the fluid.... still full from when I refilled it.

Ill get to a compression test and block test as well and do that this weekend.

 

[Bomar]

Call the guys at ACC in your neck of the woods to take a look at it if you get a questionable result.

 

[hawaiicruz]

...x2

I did this exact thing, did the Blue Water test and then a Compression test. turns out I had a bad fan clutch and radiator.

X3 not necessarily the HG. New radiator and 10,000 fluid for my fan clutch fixed my overheating problems

 

[coax]

Yep I'll echo what others have said. It "could" be the HG, but I'd sure start with the fan clutch and leaky radiator. At the age of these vehicles, cracked radiator tanks and worn out fan clutches can be common. So...don't get too dismayed yet. Check the simple stuff first.

 

[mmeister13]

So I opened the hood and started the car to see if there were any visible problems and noticed the fan wasnt spinning. Cut the engine and saw that the stupid plastic guard was jamming the fan. Fixed that so the fan is spinning now and about to do block test.

Results to be posted in the next hour.

 

[Kernal]

Has the fan been stuck this entire time, or was it spinning freely before and just now got stuck? Did the fan shroud fall down, broken mounting tabs??

 

[TEXASYETI]

So I opened the hood and started the car to see if there were any visible problems and noticed the fan wasnt spinning. Cut the engine and saw that the stupid plastic guard was jamming the fan. Fixed that so the fan is spinning now and about to do block test.

Results to be posted in the next hour.

Seems like this could be a good thing - as long as it might be the cause of your overheating. Did you run the truck after fixing the fan to see how the temps were?

Hope the block test turns out okay. Hopefully it was the fan and running it hot did not damage the engine.

 

[Funner]

fan clutch

My vote is the clutch is bad. I would think at start up you would have heard some pretty distinct thwapping sound as the fan spun and smacked the shroud. If it's shot it would be pretty easy to stop, healthy and it would have some pretty good torque on start up.

 

[mmeister13]

Has the fan been stuck this entire time, or was it spinning freely before and just now got stuck? Did the fan shroud fall down, broken mounting tabs??

I'm not sure if the fan was stuck the whole time. When I opened the hood and saw it stuck it was pinned pretty good. Not exactly sure how the fan shroud moved but I undid the bolt and set it back so the fan could spin free.

I had the block test so I figured I would do that while i had it... test turned out fine. Testing fluid never changed to yellow even after repeating the test 3 times.

Just took the truck out and drove to get some brain food to study for finals and the temp never moved from normal (about a 30 minute trip). Got to school and checked the fluid... no loss. AC was blowing cold the whole way too.

I hope that was the problem but ill keep my eye out.

Lesson learned... don't jump to conclusions. Thanks to everyone that chipped in.

PS... when I got under the car to drain some fluid from the radiator I removed the skid plate and there is oil everywhere!!! I think that explains why I'm always adding oil. Eventually the seals need to get replaced and the hoses as well but thats a project that will have to wait. Or I could just bite the bullet and do the engine swap I have dreamed of for a few years.

 

[Romer]

Glad it was an easy one. Now we all know how important the fan clutch is

On the oil, could be one of several causes. You need to clean off the oil and then see where it is leaking from.

 

[71-CRUISER]

I would be willing to bet your leak is either the dizzy o-ring or the oil pump cover o-ring. Both very common FZJ leaks. The dizzy is easy but the oil pump cover requires removing the balancer so it is a bit harder.