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Discussion Starter · #1 ·
I have a 2001.5 New Passat with the V6, currently with 49K miles. In 12/04, with 29k miles the breather tube with the integral pcv valve clogged. I noticed it because there was such a strong vacuum being pulled inside the valve covers that air being sucked through minute openings sounded like a squeaky belt. Once I figured out it really wasn't a belt squeak I took it to the dealer for repair. Unfortunately, thinking it was just a belt squeak I ignored it for a while and the vacuum also collapsed the brake booster hose which had to also be replaced. 13 months later in January 06, it clogged again. Same sqealing sound but I caught it quickly. Just the breather tube replacement this time. 10 months later and I just noticed the valve covers are under intense vacuum again (I can tell because the vacuum makes tough to get the oil filler cap off when the engine is running and up to temp). I'm sure its the breather tube again. The question I have is what might be causing these frequent failures? I can accept a periodic failure, but this seems excessive. Is there something else my friendly dealer isn't catching that could be causing this? Or, is this a common problem on the V6 B5.
 

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First of all, what is the tube getting clogged with? Have you seen it for yourself? The substance will tell a lot about where the problem lies.

That said, a clogged breather hose isn't going to cause high vacuum inside the engine block. Think about it -- if the breather is clogged, then the intake manifold can't suck air out of the engine block anymore, and it has to start sucking air through other parts of the vacuum system instead. Now, if it's doing that it could certainly suck junk into the vac system that would otherwise have sat harmlessly inside the oil pan, but still, the clog would have to be a result of the high vacuum, not a cause.

Regardless of whether you used the right logic to reach your conclusion, the high vacuum actually sounds like a problem with your throttle. It shouldn't be closing so tightly that the engine has to breathe through the breather hose (despite its name) to get enough air to maintain a stable idle.

Take the throttle off, make sure it's shiny and clean (use throttle body cleaner and a bit of scotch-brite pad if it isn't), and make sure that when the valve is closed, you can still see a sliver opening for air to get through. If you can't see a sliver opening, your throttle is defective.

Get back to us about what the breather hose is getting clogged with.
 

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if your car is a b5.5 leave the throttle body alone.
it needs to be reset and you cant do it witout going to the dealer or have a vag-com.
http://www.passatworld.com/forums/showthread.php?t=191705
Do the DBW throttles have a hard-set idle position or is that electronically regulated as well? To put it a different way, while he may need to reset the throttle if he takes it off and cleans it, will resetting it solve his high vacuum problem, or is it just a necessary step that follows cleaning the throttle?
 

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Discussion Starter · #5 ·
Thanks for the advice. I don't know what has caused the valve blockage. I have the part the dealer removed in January. I'll cut it apart to see if I can observe anything.

I do know that once the breather hose was replaced last time, the high vacuum under the valve covers disappeared. My assumption has been that with the breather hose valve blocked, the engine just begins to pull normal manifold vacuum under the valve covers. I don't know if its excessive vacuum, but just a place where there shouldn't normally be a lot of vacuum present. The car actually runs fine. No warning lights, stable idle, etc. Before I clean the throttle body I should probably find out if the engine vacuum is really running above spec with a new breather hose present.

I'll post again after the holidays once I get the new breather hose in. I'm doing it myself this time around.
 

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No, the PCV valve (or valves, on turbo engines) is what let the manifold pull any vacuum at all. If the valve was blocked, there would be no vacuum. For some reason there's TOO MUCH vacuum in the manifold, and the only place that has an adjustable airflow is the throttle. Anyway, there should always be at least a slight vacuum in the engine block.

Before you replace the breather assembly again, pick up a 1-pound sample tub of ST-140 silicone grease from www.silicones.net and use it to lubricate all of the hose connections EXCEPT the one where the breather connects to the engine block. When I put my breather assembly together using this grease, I was able to rotate the connections WITH THE HOSE CLAMPS FULLY-TIGHTENED -- which means the hoses won't bind and tear like they used to.
 
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