Mysterious squeak
07-02-2018, 10:49 PM
#1
Senior Member
Thread Starter
Mysterious squeak
I have an ‘89 4.9l and it seems to have a chirping sound coming from the engine. The same kind of sound that a worn out belt would make. But I found out that the belt is not the problem. If I put any pressure whatsoever on the clutch, the chirping goes away. I’ve got the t18 four speed manual transmission, and the issue sounds like it could be the throwout bearing. But I believe that if it was that, then it would only chirp when in neutral. So even when I’m driving along the road, in gear. I hear the chirping. But the slightest pressure on the clutch, even if I just drive while riding the clutch, the chirping goes away. Both the master and slave cylinders were replaced not before it started, but I don’t really think that should be related to my issue.
07-03-2018, 08:12 AM
#2
Senior Member
On my 1991 4.9L 5 speed manual my belt chirping was caused by the water pump bearing being worn out. It wasn't leaking 'yet', but made the belt off track just enough to cause it to chirp. I replaced the water pump with a new rebuilt one (comes with a new pulley installed) from my local auto parts store and it fixed the chirping. Just giving you something else to check 
07-03-2018, 08:40 AM
#3
Senior Member
My 89 chirped when moisture in air, it was the belt tensioner.
07-03-2018, 11:54 AM
#4
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Yes, the throwout bearing can chirp any time. Use a mechanic's stethoscope to listen inside the bellhousing. Use the open hose if necessary.
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07-03-2018, 04:59 PM
#5
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Thread Starter
I fixed the problem and it actually ended up being super simple. The old slave cylinder had a plastic cap on the end of the pushrod. The new one doesn’t. So the metal on metal of the pushrod was making the sound. I fixed it by putting some grease on the end of the pushrod.
07-03-2018, 11:36 PM
#6
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I missed that it was a T-18 (which has an external slave), so I assumed it was concentric. You should put all the truck's details into your signature:
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