Hi i tested my 1.8t's compression and it was very low. its at 90 on all cylinders. Car is running fine. Timing is dead on when i did it last year and still is. Does this mean my valves are bent? Its really disappointing as i almost got my car to mint flawless shape inside out. no more codes etc. Also my car is running fine, no loss of power or anything. What could be going on?

 

Any thoughts?

 

For starters, are you absolutely sure you performed the test correctly? For all cylinders to be in the 90s that means all the valves/pistons/rings are roughly in the same condition. So if one valve is bent, they'd all have to be bent. And if you did in fact do the test correctly, you're in need of an engine overhaul... the factory service manual suggests ~140psi (I think) as the low point for a properly functioning engine.

 

The motor has to be at temps or you get a low number. 180psi is new and it's lower than 140 for bad. It sounds like you are ok if they are all basically the same psi. Test again and you should be fine

 

A low compression on all cylinders could mean the timing is off. That's what I'm dealing with now 100-110 on all cylinders. Do you have any codes? Just because you don't have a cel doesn't mean you don't have codes. Start there. Then I would recommend a leak down test.

 

Like cincytt said make sure your engine is at operation temp because it causes the metals to expand and seal better. Having the same number across the board is good, although if you have 90 across the board your engine must have a ton of miles. If you do the test once your engine is warmed up and the numbers are still low, pour about a teaspoon of oil in each cylender, if the compression temperarly raises, your piston rings are super worn. I thought 200 psi was factory? My 2000 a4 atw still has 180 across the board!