Major crankcase pressure and compression issues

AUSTIN5432W33

MEMBER
2006 VOLKSWAGEN JETTA
2.5L
5 CYL
2WD
AUTOMATIC
317,000 MILES

I've been letting my friend use my car for about 3 months now and I just got it back today. So I did my normal check over the engine it was low on oil so I open the cap and a whole bunch of pressurized air came out, so I thought it was bad piston rings so I did a compression test and these are the results cylinder one 60 PSI, cylinder 2 120 psi, cylinder 3 73 psi, cylinder four 146 psi, cylinder 5 84 PSI, but the thing that's weird is after it got to 60 PSI it held I would think that if the piston rings are bad it was slowly lose pressure over time but over the span of five minutes it barely have lost any pressure at all. Also I'm having a very big problem with crankcase pressure I checked and the valve cover gasket was blown out and I just replaced it. Update: after more digging into the motor I have found that the vacuum pump line to the brake booster has a major leak and the vacuum pump is leaking oil. Could this cause major crankcase pressure or weird compression readings? If anyone has any answers or ideas what my problem could be please let me know.

3 Replies

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello,

Cylinders 1, 3, and 5 are all low. I would recommend doing a wet compression test to see if it is worn piston rings or another problem. To do this pour a teaspoon of clean engine oil in the cylinder that you are testing. Then do a normal compression test on that cylinder. If the numbers come up on that cylinder then that confirms that the rings are worn. If the numbers stay the same then the piston rings are not the problem and you will need to look towards a blown head gasket, burnt valves, or a cracked engine block or cylinder head. Please let us know how it turns out.

Thanks,
Alex
2CarPros

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Monday, March 2nd, 2020 AT 11:40 PM

AUSTIN5432W33

MEMBER
7 POSTS

Did some more digging and the vacuum pump had a big leak in the hose going from the vacuum pump to the break booster I fixed that leak and it eliminated the crank case pressure building up. But the abs traction control and a steering wheel symbol and engine light are on I haven't checked the compression yet but it seems to run the same with no issues could the leak from the vacuum pump cause the abs, traction control and the steering wheel symbol stay on? I've cleared all fault codes multiple times taken the battery out and everything and the lights are still on. And if someone could let me know what the steering wheel symbol mean I'd appreciate it. Thank you

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Thursday, March 5th, 2020 AT 5:41 PM

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello,

No, they have nothing to do with each other. In the diagrams down below I have included a diagram with callouts of your vehicle's instrument cluster. Please go through this guide and get back to us with what you find out. I hope this helps.

Thanks,
Alex
2CarPros

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