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9,106 Posts
Discussion Starter · #1 · (Edited)
V6 PCV system replacement (AHA and ATQ engines through mid-2002)

The following writeup covers the replacement of both the PCV valve (with tubing) and the suction pump in early B5 V6 engines, most commonly found in the VW Passat, Audi A4, and Audi A6. Failure in these parts is the most widespread and common reason these engines experience valve cover gasket and cam chain tensioner gasket leaks (VCG and CCT) common, in fact, that VAG has actually issued a TSB to dealers, urging them to be sure the PCV system has been replaced before doing any gasket work.

Please be sure to cross-reference these parts with your vendor, model, and year to ensure you are purchasing the correct items.

Replacement parts list--final alpha characters are often superseded:
078 103 224 R (078103224R) - PCV valve and tubing ($55-$70 online)
058 133 753 D (058133753D) - Suction pump ($20-$30 online)

Tools needed:
Phillips-head screwdriver
10mm socket
Wire cutters (Needle-nose pliers also recommended)
Small hose clamps (x4)
Flashlight or headlamp

Why change your PCV valve and tubing? What does it do? Well, in a nutshell, the PCV (positive crankcase ventilator) allows the excess air pressure in your oil to escape, rather than just build up under the cylinders. These can also cause the pressure that creates--or worsens--gasket oil leaks in the valve cover and cam chain tensioner. The air is usually a product of blow-by, or air eeking past the pistons during the compression cycle. It's a normal part of a car's operation, but tends to get worse as a car ages. So remember, just like your grandpa, the older it gets, the more gasses need to escape. And just like the old man, the plumbing may be a little more brittle or clogged than it used to be.

(Please note the following pics are from two different jobs in 2005 and 2009. Be sure to read all the way through, since some of the labor, like removing the vacuum hose plate, can benefit your replacement efforts!)

First of all, let's get familiar with the V6 engine compartment as it relates to this job. Remove the cosmetic plastic covers if you haven't already.

With a COLD engine, the first step is to remove the PCV from the passenger-side valve cover. This is done by squeezing on a black compression ring around the outside of the tube. Then just pull away from the engine. You're done on that side...1 down, three more to do.

Next, remove the three phillips screws from the coolant reservoir. Remove the coolant sensor connector from the bottom for extra clearance and set the reservoir on top of the engine.

There are three more of those compression rings here, each of them a bit harder than that first one. Just do the best you can, and don't be afraid to cut them apart for better access. You'll be replacing it all anyway, but just be sure you ONLY cut on things that correspond to the part you just bought. There are some other tubes under there of the same material and diameter, but like a vasectomy surgeon, just randomly guessing is not generally a good idea.

The one additional connection comes straight from the PCV valve itself, and bends up toward the engine in a 90-degree elbow. VW decided that they should make life tough for everyone along the way, so they applied the ubiquitous "single-use hose clamp of doom" here. Just careful tweak it open with your needlenose or wire cutters until you can slide the tube and barb apart and slip the clamp off.

Now the old PCV system has been removed and you can just replace it with the new one. Ideally, try to use a screw-type hose clamp where the one-time clamp was before. However, being a low-pressure system, you can get by with a zip-tie, but it probably won't last very long. And don't forget to put the barbed strap back over the wires/tubing, and be sure to replace the coolant sensor before you screw the coolant reservoir back in. Otherwise you'll get an angry dash icon the next time you start up.

Alrighty! Now can you tell which hose is the new one in this pic?

And while it wasn't completely clogged, who wants hoses that look like this?

Now let's move on to the suction pump. If you're doing this at the same time as the PCV system above, you might want to go ahead and read the instructions below to remove the vacuum hose plate--this will allow you extra clearance for the rest of the PCV system, as well. The labor overlaps a lot.

First, identify the vacuum hose plate at the rear of the engine. It sits on top of the intake and throttle body. The original hoses are black and green braided fabric. In this pic, they're all black 3.5mm ID silicone. Remove the three bolts and four wiring harnesses as indicated:

Yes, I know I spelled "receptacles" wrong in the pic above. This was intentional, so as not to intimidate any AudiWorld and AudiZine visitors with the supreme competence and know-how of PassatWorld :D

You may have to pull off a vacuum hose or two at this point, since you want to be able to rotate the vacuum hose plate up on end, allowing you access to the stuff underneath. Now you can see the suction pump.

My suction pump was attached with one screw-type hose clamp and two crimped hose clamps. As with the other clamps, just work on it until you can pry it loose from the rubber hose.

If you've made it this far, reinstallation is pretty self-explanatory!

Happy DIY
Ash (PassatWorld: ashman78)

3,838 Posts
Very nice writeup :thumbup:

Also a note to all, you want to do this *long* before or during a VCG replacement. Please don't do a VCG replacement without a clean PCV system. Waste of time, effort and $$.

Wish the entire PCV stuff on the 1.8T was this easy :banghead:

RETIRED Super Stealth Moderator
27,881 Posts
I've done this job twice (Passat V6 and Audi V6).
one thing to add... once you have released the second squeeze fitting on bank 2, it is much easier to release the next one IF you take the time to remove the intake from the MAF to the throttle body.

also, there is one more piece to the PCV system that is not listed here on B5 V6 motors - it is the lower portion, one plastic hose, that actually goes to the crank case.

Grinding Gears...gone fishing!
22,610 Posts
good job on its way to its new home in the info base, one way ticket :)
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