I have a fan hub/clutch, that leaks air. can hear it hissing air. I put some soap & water on it. it leakes pretty good. I thought. A fellow truck driver looked at it & said, it is nothing to worry about. that he has seen even new or rebuilt one's leak. $550.00 for a rebuilt horton & $175.00 labor. is this a serious problem or just another airl leak, like many others?

 

Failed fan clutch can make your motor overheat and you can end up with a big time bill...

CHANGE IT !!!!!!!!!!

 

thank you.

 

I'm not understanding how a fan clutch that leaks air can cause the engine to over heat.

I help change a fan clutch on an M11. Or was it an N14? I can't remember. But it was a bugger. Not much room to work without taking the rad out. IIRC, we cut a section of the fan shroud out so we could remove the fan. With the fan out of the way, there is room to work. Then we pop riveted the piece of shroud back in place.

Me, I don't like air leaks. I figure every time that air dryer sneezes, my compressor dies a slow death.

 

I dont know how it affects the temp. my main concern is the leak won't leave me stranded somewhere. the other driver said it will not. & if the leak got real bad, all I had to do was, plug the line going to the fan hub & that would stop the leak until I got home. I am most positive this leak has existed for quite some time, due to my tank's losing all air in 3 hours, when truck is off. I have soaped every air line & fitting I could find, but tcould never find a leak other than a real small one here & there, then yesterday my son heard it from about 3 ft in front of the truck. ( I have real bad hearing) soaped it & bubbles everywhere. my air dryer sneezes every 10 second's. could this leak cause that?


when my dryer 1st started popping off so frequent, i was told it was the govener. put one on, no difference. told air dryer, put new one on, no difference, told air compressor. put one on, no difference. been sneezing for 2 years. had in shop. no one can tell me why it pops off so much. cost too much already by process of elimination & still got the problem. the only thing I can say is everything I had replaced had over 1 mil miles on it, so it probably was at the end off it's life anyway. I just wished 1 of the things I had replaced fixed the problem. downtown, cost me the most.

 

I would replace the fan clutch as soon as possible. I don't like air leaks, either. You don't want to wait until it fails completely. Worst scenario, if it comes apart it could damage your radiator and and hood.

 

First of, any audible air leak will put you out of service.

A fan hub leaking air like that will run the fan all the time, and fan hubs can wear out so much they start falling apart, so ya, it should be fixed asap.

Any air leak can make your compressor continuously load or frequently cycle over and over.

Air dryer sneezing every 10 seconds... I would have changed the easiest and cheapest part first.

Those pop off valves on the bottom of the dryer screw up all the time, very common and could cause your problem with the air drier.Very common in my enviroment. (dust, dirt, ice, etc.)

Sometimes they sound like a rattle snake between sneezes and sometimes they just purge air between sneezes.

Really easy to change out, last one I seen was just a snap ring holding the spring/plunger assembly in.

 

I did change entire air dryer it came with the everything in tack. I know about the bottom valve. it had a constant leak years ago & I replaced just it. that fixed the leak, but that was easy, you could see & hear where the leak was coming from. but this last time, I replaced whole dryer. I forgot about the d.o.t. last time I was stopped the officer stood real close to my grill to get a good look at my windshield, to look for any crack's. anyone that close would hear the air leak, cause I have a cab over, & you can get real close to the front end. I will say as of now, my fan does not run all the time. reguardless. I am ordering part tomorrow & will have on asap. thanks for the advice folks.

 

Based on your diagnosis, it sounds like all you need a minor rebuild seal kit.

If it's a Horton fan clutch- there are two threaded holes on the housing. You might want to make sure you have two grade 8 lockout bolts handy. If the clutch goes out completely you can screw in the bolts which will kept the cooling fan engaged 100% of the time. Your MPG will go down, but at least you won't overheat your motor.

It's been a few years since I rebuilt mine. Think I paid about $70 for the seal kit, which is nothing more than a few O-rings, some hi-temp grease and a new Sentry safe plug. Took me about a half a day, with basic tools.

 

You probably have multiple problems, and you might have solved a few of them already. The fan clutch will only get air while the engine is running, so it is not a "loss of air while parked" problem.

You've covered a lot of fittings, but have you really hit every single one? What about the fittings in the dash, on ABS relay valves, on top of the transmission, on the firewall, etc..

After that absolutely cover every single air bag. I once had a hole right in the middle of one. Couldn't hear it. You also have to check exhaust ports on all the valves, as well as the arms coming out of leveling valves. Another possibility is the quick drain cocks on your air tanks. Sometimes they need to be snugged a little more.

As far as your air dryer pissing off every 10 seconds, that's a serious problem that should be addressed. Are you losing enough air pressure during these 10 seconds (say from 120 to 100) to cause your air compressor to turn on or are you barely losing any air? If you are losing that much air you need to get it fixed. That could put you in serious trouble, plus air dryers can only handle a compression event every 120 seconds or so.

If it's not an air leakage problem, it may be the governor, air dryer or the air compressor itself. There are valves in the air compressor that can bugger this up. Look closely for any leaks on the lines going to and from these 3 items.

IMO you should absolutely get rid of ALL quick disconnect fittings and replace them with compression fittings. That's what I'm doing. I've finally got my truck to compress every 20 minutes or so. It's been a battle. I've probably changed about 20-25 fittings so far, and I'm just going to change the rest(some of them cannot be changed to compression fittings due to their design, blasted Volvo!).

After all this is done (checking all fittings, valves, relays, drain cocks, sensors etc..) you have to look at air actuated systems that could possibly drain internally due to bad seals, like transmissions. I've heard of the range splitter actuator leaking right into the tranny.