Failing Fan Clutch Symptoms

[Craig Dickinson]

Can anyone tell me the indicators for a failed fan clutch? I've got a high pitched squealing noise coming from the front of the engine. Initially thought it was the serpentine belt, however the noise is still there after I replaced the belt. Seems to quiet down when the engine is under load.

 

[Jerry Bransford]

Could be a bad idler pulley, could be a bad fan clutch. I'd lean more toward a bad idler pulley.

 

[Chris]

I agree with Jerry, this might actually be a bad idler pulley. The bearings in those things go bad. It happened to mine believe it or not, and was making the exact sound you described.

 

[Craig Dickinson]

Thanks guys. I'll give it a shot.

 

[Chris]

That's what I would do first. It could indeed be a bad fan clutch, but the idler pulley is so cheap, I would just rule it out first anyways.

 

[Craig Dickinson]

Sorry it has taken so long to get back with everyone, it appears that I have opened the proverbial "can of worms". I replaced both the belt tensioner and the idler pulley. They both needed replacing as there was a lot of play in both pulleys. And while this seemed to help, there was still a high pitched squealing sound coming from the front of the engine. I bit the bullet and bought a new water pump, fan clutch, thermostat and radiator. I know the thermostat and radiator are potential sources, but it seemed like a good idea just to rebuild the entire cooling system. So here is my current dilemma - I go to remove the bolts from the thermostat housing and the head off of the top bolt snaps off. I was able to remove the bottom bolt and wiggle the top bolt free. Its still in the head, but it is moving, so I think I can get it out with a bolt extractor. My question for everyone is does anyone have the specifications on this bolt? Can't seam to find them at parts stores or online.

 

[Jerry Bransford]

To insure I give you the right size bolt threads, what model year TJ? Is there any part of the snapped off bolt that is above the surface of the head? If so perhaps vise grips can grab it enough to get it out.

Keep in mind those bolts only snap when whoever reinstalled them overtightened them to begin with. Use no larger larger size ratchet wrench than a 3/8", it's too easy to overtighten small bolts like that with a 1/2" drive ratchet.

 

[Craig Dickinson]

Its a 2000 TJ with the 4.0 liter inline 6. I completely agree with your statement on over tightening. I think the proper torque is like 13 ft-lbs.

 

[Jerry Bransford]

Those two bolts are:

.312-18x2.38
.312-18x.970

.3125 is a 3/8" so that'd be my guess... that Mopar just dropped the 4th digit.

The factory says 15 ft-lbs. for those two bolts. Use a gasket, not RTV between the housing and the head.

 

[Craig Dickinson]

Those two bolts are:

.312-18x2.38
.312-18x.970

.3125 is a 3/8" so that'd be my guess... that Mopar just dropped the 4th digit.

The factory says 15 ft-lbs. for those two bolts. Use a gasket, not RTV between the housing and the head.

Thank you sir! I really appreciate the help.

 

[Craig Dickinson]

Should any type of sealant be used on the threads of the water pump bolts or thermostat housing bolts?

 

[Craig Dickinson]

Those two bolts are:

.312-18x2.38
.312-18x.970

.3125 is a 3/8" so that'd be my guess... that Mopar just dropped the 4th digit.

The factory says 15 ft-lbs. for those two bolts. Use a gasket, not RTV between the housing and the head.

Should any type of sealant be used on the threads of the water pump bolts or thermostat housing bolts?

 

[Jerry Bransford]

Should any type of sealant be used on the threads of the water pump bolts or thermostat housing bolts?

No. And don't use RTV anywhere in the cooling system either, all you need are standard gaskets and scrupulously clean gasket seating surfaces to make a leak-proof system.

 

[g.hayduke]

I know this is an old thread but I'm having trouble finding accurate info on whether or not the water pump bolts need sealant or not. And what type of sealant is best if it is needed. @Jerry Bransford answer above seemed the most definitive but I have have some reasonable doubt for a really solid reason.

I currently have my water pump off the engine. It's an '05 LJR with the original 4.0 and looks like the original water pump. One of the water pump bolt holes goes all the way through into the water jacket. It's the one on the passenger side. All the other bolts seem to go into blind holes but not that one. So, shouldn't that bolt have some type of sealant on it? Will I not have at least some seepage there without some sealant on that bolt? @mrblaine, what say you?

The FSM is silent on the question. One YT video shows a guy globbing massive amounts of teflon sealer goop on all the bolts. It looked like there was some sort of sealer on the factory bolts, some yellowish residue.

Plumbing type sealants and teflon tape are really intended for tapered pipe threads which a bolt is not. How about blue Loctite( since I have some)? Would it seal and hold with the heat and pressure?

I'm guessing there is a product designed specifically for this but I don't know what that is. If that bolt can magically prevent leakage without any thread sealant, please tell me how that works.

 

[mrblaine]

I know this is an old thread but I'm having trouble finding accurate info on whether or not the water pump bolts need sealant or not. And what type of sealant is best if it is needed. @Jerry Bransford answer above seemed the most definitive but I have have some reasonable doubt for a really solid reason.

I currently have my water pump off the engine. It's an '05 LJR with the original 4.0 and looks like the original water pump. One of the water pump bolt holes goes all the way through into the water jacket. It's the one on the passenger side. All the other bolts seem to go into blind holes but not that one. So, shouldn't that bolt have some type of sealant on it? Will I not have at least some seepage there without some sealant on that bolt? @mrblaine, what say you?

The FSM is silent on the question. One YT video shows a guy globbing massive amounts of teflon sealer goop on all the bolts. It looked like there was some sort of sealer on the factory bolts, some yellowish residue.

Plumbing type sealants and teflon tape are really intended for tapered pipe threads which a bolt is not. How about blue Loctite( since I have some)? Would it seal and hold with the heat and pressure?

I'm guessing there is a product designed specifically for this but I don't know what that is. If that bolt can magically prevent leakage without any thread sealant, please tell me how that works.

View attachment 350399

We never put any sealant on that bolt but if I was worried about it, coating the threads with some good RTV wouldn't be the end of the world.