KNOCKING WHEN COLD!!!????

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Dec 8, 2001 | 03:59 PM

vtecetr

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KNOCKING WHEN COLD!!!????

O.k. here we go I have a 86 4000 q 2.2 5 cyl. (duh) but any how when i start it in the a.m. or after it has been sitting for more than a hour it knocks for about 3 to 4 min. then goes away? sounds like a rod but that would not go away. may be a spun bearing? or wrist pin? please help don't wan't to trash motor quite yet!!! thanx!

Dec 9, 2001 | 04:35 AM

SteveAngry

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Re: KNOCKING WHEN COLD!!!????

Knocking or ticking?

Ticking will be the lifters...

Knocking is caused by the aux. brake booster(whatever it's called?)...

To cure nosiy lifters: try Mobil 1 and a good German filter or replace the lifters...

To cure the knocking: You can either remove the aux. brake booster completely as it is not needed, or open it up and clean the rod inside...

Neither problem is terminal...

Steve
Michigan

Dec 9, 2001 | 08:46 PM

vtecetr

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Re: KNOCKING WHEN COLD!!!????

WELL IT IS DEFINATELY NOT LIFTERS.
KNOCKING THOUGH IS LIKE A RAPPING SOUD GIVE THE MOTOR SOME THROTTLE AND THE KNOCKING SPEEDS UP WITH THE MOTOR STILL COULD BE AUX. BRAKE BOOSTER?

Dec 10, 2001 | 06:03 AM

Evilclown

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It's probably the vacuum pump(aux booster).

You can take the thing off and either block off the hole or remove the rod that actuates it. Like Steve said, you don't really need it, and that should cure the knocking. These bottom ends are pretty well bulletproof, there isn't much you can do to break them.

Again, please lose the caps.

Dec 10, 2001 | 03:28 PM

Chris in VA

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Wait up

Ok, let's clarify here before jumping to conclusions. First, RARELY do the engine bearings/wrist pins go bad on this engine. Audi overengineered it, so it's unlikely that's the problem. One thing we need to check here is the difference between a loud 'clack' and a deep 'knock'. Clacking is the par for Audi/VW's and is caused by the lifters not getting enough pressure for one reason or another. The vacuum boost pump acts just like a lifter and will sound VERY similar, just a bit louder. All you have to do is get a long screwdriver, put one end on the pump and listen with your ear. Loud? Then you need to take the rod out of the pump. If not, then take it to a mechanic for further testing with the rest of the engine. Try this and get back to us.

Dec 11, 2001 | 03:51 AM

StormChaser404

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Do 87.5 CGTs have this pump? If so...got a pic?

If 87.5 CGTs (NG engine) have this pump, can domebody point me to where I can find a pic of it? If I don't need it and it may be the cause of my cold ticking/clacking I might as well ditch it...

Dec 11, 2001 | 04:51 AM

vtecetr

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Re: Do 87.5 CGTs have this pump? no pic but here is a good description of and location

If you are looking at the motor from the front it will be on the right side of the cylinder head and the vacume line off of the brake booster will go to the booster then the intake manifold. just take out the 2 bolts pull the rod out and put back on . thats it done!