2000 alh low compression when warm?

I bought this 2000 beetle TDI 5spd 185k cheap because a shop in town replaced the turbo and timing belt and it would not run right when they finished it so i got it cheap. It smokes white nasty unburned diesel fumes enough that people thought my car caught fire!!!

I checked there timing and injection timing and they where correct. I then checked compression it comped out cold at 290-300-325-325 Then I let it get up to temp and I got 200-300-200-300 The longer it runs the more it smokes and harder it is to start.

I pulled the head to check for valve interference damage and found nothing so I pulled the valves out and they are all the same length and straight as an arrow no deformation on the steams. Evan the seal faces looks decent. very minimal play in the valve guides

I checked the piston protrusion height to check for a bent rod and all 4 pistons where between .040in & .042in above the deck height sounds normal to me it has a 2 dot head gasket. The pistons mover ever so slightly in there boars back and forth and side to side is that normal? The cylinder walls are clean no scratches they just looked polished with very minimal barley noticeable cross hatching. And a very slight lip at the top of the cylinder

So either the rings just gave out all of the sudden or the lifters are holding the valves open? It did have some really thick oil in the engine when I got it almost like motor honey nasty sticky stuff. I changed it out for standard Rotella but it made no difference for the smoking.


I am going to hone and replace the rings and rod bearing in the car and replace the lifters and valve seals. And other ideas on what to check?

I'm pretty sure you're aware, but the symptom isn't really low compression when warm. Your compression numbers are low altogether, even those cold #'s you listed were way below spec.

willbhere4u said:

It smokes white nasty unburned diesel fumes enough that people thought my car caught fire!!!

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Incomplete combustion or excess fuel would typically produce black smoke.
Is it holding coolant level, or is the cooling system pressurizing (ie, indications of head gasket problem).
Is the EGR cooler in place?

willbhere4u said:

It did have some really thick oil in the engine when I got it almost like motor honey nasty sticky stuff.

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Standard schiester trick for trying to hide low compression or an otherwise tired engine.
Once you get the motor running right you better go through all of the fluids really close. Hopefully this isn't an automatic transmission.

Yea I know the compression is low but anything over 275 should at least fire. My question is where is it going why is it so low and why is it lower when its warm. The 2 cylinder with 300 psi where dry carbon looked normal the other 2 with 200psi wher wet with diesel fuel like they where not running at all.

The coolant was fine no pressurization issues ran right on temp the head gasket looked to be in good shape when removed. The EGR cooler was in place and hooked up as was the egr. The car misfired and smokes until it gets on boost then ran normal and had good power and almost no smoke around 4k rpm with 10psi max boost.

When I first got the car it would not rev over 1500 rpm until I disconnected the EGR vacuum line there was so much smoke in the intake it was almost impossible to start. I took off the boost hose at the intake and it was pumping smoke out of the intake manifold like bent valves while trying to start it. so I disconnected the EGR vacuum line and the smoke cleared then it started and ran ok but was still smoking badly and misfiring

Was this car ever run on vegetable oil, IE grease car?

That would explain why there is no compression. The thick oil produced more compression when cold. New rings and pistons, rods, and a rebuilt head should get you back on the road.

never been run on grease

Why replace the rods? The old one are still in spec. I'm going to pull the pistons this weekend and and measure the cylinder bore's if there in spec I'll hone it and replace the rings I'll have to inspect the pistons and see if there reusable. If not I will have to have it bored out one size and get new pistons

Sounds like you know what you're doing.

d2305 said:

Sounds like you know what you're doing.

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nobody's ever accused me of that before

It went in to the shop running and driving the turbo leaking a little oil they replaced the turbo with a gt1749 and a new timing belt then bam no compression afterwards. That's why I was wondering if the lifters where over pumping and holding the valves open. Maybe because of the thick oil??? The inside of the engine was suprisinly clean no metal shavings no dirt or debris or deposits.

I have to ask.

Do you have the proper tools to set the cam timing and injection timing ?

Are you using quality compression gauge, not harbor freight or something ?

If it had good compression before you took it to the shop and not after, Have you spoken to the shop about this ?

ultrasparc said:

If it had good compression before you took it to the shop and not after, Have you spoken to the shop about this ?

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The OP didn't own the car before it went into the shop.
He bought it in this state for cheap because it was a little bit of a project.

willbhere4u said:

I bought this 2000 beetle TDI 5spd 185k cheap because a shop in town replaced the turbo and timing belt and it would not run right when they finished it so i got it cheap.

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willbhere4u said:

It went in to the shop running and driving the turbo leaking a little oil they replaced the turbo with a gt1749 and a new timing belt then bam no compression afterwards.

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CopaMundial said:

The OP didn't own the car before it went into the shop.
He bought it in this state for cheap because it was a little bit of a project.

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oops, yeah, I kinda missed that, he still implies the compression was good before the shop. That kinda rules out bad rings, right ?

Ohh, and willbhere4u, I don't think thick oil would make valves stay open.

ultrasparc said:

...

Do you have the proper tools to set the cam timing and injection timing ?

...

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I'll repeat as this is a critical question. And the follow-up: have you gone back to the beginning and reset the timing by locking the cam, checking the TDC mark on the flywheel and then pinning the pump?

I believe the head is already off and I assume the oil pan is dropped. At this point from my novice point of view it seems to make sense to take the pistons out and get the rods measured at a good machine shop, then if they're okay, do as he's described, new rings/rod bearings/head rebuild and put it back together.

But, the question of having the right tools and software is a good one, and I'm sure the OP realizes he's going to need that stuff to get his car going again. I'd be tempted to send the rods/pistons/head to Frank and let him evaluate.

I took the head off and measured the piston protrusion and it was dead nuts on then I notice the cylinder walls where deformed on the 2 cylinders #1,#3 that had lower compression #1 200psi #2 300psi #3 200psi #4 300psi apparently the car had been running with the EGR stuck open. and must have carbond up the rings really badly and that wore the cylinder boars it had a double step on the rear of the cylinder walls.

But the good news I found an engine on Craigslist for $750 with 110k from an automatic with a newer gt17 Garrett turbo and 11mm AT injection pump. Now the car has a new performance clutch/flywheel new again timing belt with quality parts this time. And the Cat has been cored out and the EGR deleted. I'm going to send the old injectors out for new performance tips. and maybe through a tune at it later.

The only thing I broke during the swap was the stupid plastic connector to the shift cable that keeps it from sliding off the transmission lever. All in all it went pretty smooth. I just have to put a new oil pan on it tonight old ones plug was stripped out and fill it up with oil and coolant and bolt the front clip back on and go for a drive

will it be alright to run it with the 11mm AT injection pump and AT injectors for now? Until I can have the manual injectors rebuilt? Also will it need a tune to run with slightly bigger injectors and pump and turbo? Or will it be ok for awhile. I figured a tune will make more power with the other mods but will it damage it to run with out one?

Thanks Will