1999 Jeep GC Mechanic Stumper - LOUD at startup

MILLEMIGLIA

MEMBER
1999 JEEP GRAND CHEROKEE LAREDO

Hi there,

I have a 1999 Jeep Grand Cherokee. I've had this problem for over a year, and no mechanic had any clue what the problem was.

Every time I start my Jeep in the morning, the engine is SUPER loud. When I rev, it gets even LOUDER. The only way to bring the engine noise down is if I rev over 4500rpm. As soon as I do this, the engine sounds nice and quiet like it should.

If I have the car running for a while - I can turn the ignition off, and turn back on with the normal quiet start sound. If it's left go for a few hours - the Loud noise will return on startup.

I have taken this to 3 mechanics - with no answers.
Actually, 1 mechanic didn't even acknowledge this was a problem.

When I took it to a Jeep dealer orginally they said it was the fan clutch. I replaced it, and it orginally fixed the noise. Then after a few months, the loud start up noise came back. I had it replaced yet AGAIN, but this time it didn't solve it.

Any answers mr. Mechanic?

Thank you so much in advance,
Aris

1 Reply

RASMATAZ

MECHANIC
75,992 POSTS

Are you sure its the right type fan clutch-there's Thermal and Non Thermal fan clutches. You need to confirm this.

Worn bearing on the water pump shaft will usually cause the water pump to leak and/or make noise, but not always. Remove the fan clutch and see if the play is in the water pump shaft. If it feels tight (no play or wobble), replace the fan clutch.

I recommend you check the water pump thoroughly it might be the one that's causing the problem to the fan and make sure the fan are not overtorqued.

The water pump ages with the fan clutch-just like liters and camhaft/rotor and distributor cap. One goes the other follows.