Hazmat1071

Hello,
I’ve got a 2001 cab tiptronic with 50k miles.
left work today and heard knocking after I got gas.
It’s happening at idle, but not when I rev the engine.

I know worst case scenario is bore scoring, I’m hoping it’s something else. This has been my daily for the past two years; should I stop driving immediately and what tests should I be asking the mechanic to run?
thanks

Hazmat1071

Here's a video of the ticking...

hbdunn

Take the accessory belt off and see if it still does it.

All you need is a 24mm wrench or socket.

Mike Murphy

That’s a pretty heavy/deep knock. Bore scoring sounds lighter, like a lifter.

Is the engine running rougher?

Hazmat1071

The engine is running normally, no loss of power or lagging.

Hazmat1071

Thanks, I'll try that when I get home

Yogibara

That sounds like piston slap to me. Let us know if the sound goes away when you remove the belt.

Hazmat1071

Update:
Mechanic stated it not bore scoring and sounds like something is loose internally and has to drop engine and disassemble to diagnose. The minimum quoted is 5k to take apart and reassemble. Anything else I should be doing while the engine is accessible?

Gary12000

Did you take it to a Porsche specialist? did he actually say "something is loose internally"

5k minimum doesn't sound like a very reasonable way to say it could be a full engine rebuild,
that sounds like its a mechanic who is going to take all your money.. also how would he know its not bore scoring if he didn't inspect it with a borescope,

maybe i'm overreacting as i don't know your mechanic.. buyer beware...

Just stating that i have heard that Slakker Engineering in Oklahoma is now doing Hartech Rebuilds, if i was fully committed to engine out i would be towing my car to those guys and getting a perfomance built engine...

Another idea would be to ask your mechanic to do a bit more investigation before committing to an engine out, Three things:-
1. A compression check on all cylinders both wet and dry
2. Carefully remove the oil filter and be there when he cuts it open to see if you have any metal in the filter.
3. Drop the oil pan to do a proper bore scope for bore scoring..

All that can be done with the engine in the car... at a much lower cost...

Mike Murphy

Opening the engine is a can of worms that could lead to a complete rebuild/refresh, costing $15-$30k. Be prepared for lots of potential little things that could lead down that path, including oval bores, worn bearings, head work, chain and tensioner pads, RMS, AOS, clutch, etc. I would only do a rebuild at the best shops that are known for rebuilding these M96 engines.

It’s not that you have to do all these things, but once the engine is apart, it might not make sense to put it all back together damaged for $5k.

sublm8

“Something is loose internally”? Did he give you any further ideas? If not, I’d definitely get another opinion before dropping and tearing into the motor, especially if he didn’t do the basic starting steps mentioned by Gary12000 above. No way are you going to get out of dropping and opening the engine for $5k.

And - do you know if the sound disappears off idle? If it goes away with revs it’s definitely not just something loose.

Not saying it isn’t something worrisome, but it’d be a shame to tear the engine down for a single weak lifter that pumps up off idle. Someone recently on a FB group had what they thought was bad bore scoring, turned out to be the resonance flap in the intake had a little play.