Manifold vacuum line test and replacement
07-31-2006, 06:42 AM
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Manifold vacuum line test and replacement
My mechanic was checking my car with me a couple of months ago and showing me things to look out for as potential failures, since the car is at 55k miles. I already posted a thread about the in-line check valves a couple of weeks ago. This one is about a three-way vacuum hose at the back of the engine, twelve o'clock as you look at your I-4 engine bay. The original part number for my MY2002 is 06B-103-221-A.
The diagram below shows the three way hose as item #6.
<img src="http://pictureposter.audiworld.com/61481/vac_diagram.jpg">
When new, you can pinch the side of the hose and it is rock hard. As the car ages, the hose will have a small amount of oil pass through it and wear the rubber. The hose effectively wears from the inside out. As it wears, it cracks on the inside and becomes soft. The easy test to check wear is to pinch the hose. If it's firm, you've got time. If it's soft, and it takes a few seconds for the dimple from your pressure to push back out, your hose is in an advanced stage of wear and could start leaking.
On my car the part was quite soft and so I ordered a replacement from the dealer (about $25). The original part had an -A suffix, and the present replacement has a -P suffix. The replacement is slightly curved whereas the original is kind of squared off. To replace, remove the OEM clamps (the bottom one is tricky), pull the hose off, fit the new one on and replace the clamps (I used the threaded clamps, since I'll probably do this again at 100k miles).
I cut open my old hose, and while the picture below is blurry, you can see that the hose was in the process of crumbling away. All that stuff was beginning to be circulated in my engine, or getting stuck somewhere.
<img src="http://pictureposter.audiworld.com/61481/hose_inside2.jpg">
The finished replacement is shown below:
<img src="http://pictureposter.audiworld.com/61481/engine_top.jpg">
In order to get the hose on, we loosened the hard line to the left that is attached to the replacement hose, and then tightened it back once all the hoses were in place and fit.
This was a simple squeeze test that prevented a potentially painful fix later. Hope it helps you guys avoid issues down the road.
The diagram below shows the three way hose as item #6.
<img src="http://pictureposter.audiworld.com/61481/vac_diagram.jpg">
When new, you can pinch the side of the hose and it is rock hard. As the car ages, the hose will have a small amount of oil pass through it and wear the rubber. The hose effectively wears from the inside out. As it wears, it cracks on the inside and becomes soft. The easy test to check wear is to pinch the hose. If it's firm, you've got time. If it's soft, and it takes a few seconds for the dimple from your pressure to push back out, your hose is in an advanced stage of wear and could start leaking.
On my car the part was quite soft and so I ordered a replacement from the dealer (about $25). The original part had an -A suffix, and the present replacement has a -P suffix. The replacement is slightly curved whereas the original is kind of squared off. To replace, remove the OEM clamps (the bottom one is tricky), pull the hose off, fit the new one on and replace the clamps (I used the threaded clamps, since I'll probably do this again at 100k miles).
I cut open my old hose, and while the picture below is blurry, you can see that the hose was in the process of crumbling away. All that stuff was beginning to be circulated in my engine, or getting stuck somewhere.
<img src="http://pictureposter.audiworld.com/61481/hose_inside2.jpg">
The finished replacement is shown below:
<img src="http://pictureposter.audiworld.com/61481/engine_top.jpg">
In order to get the hose on, we loosened the hard line to the left that is attached to the replacement hose, and then tightened it back once all the hoses were in place and fit.
This was a simple squeeze test that prevented a potentially painful fix later. Hope it helps you guys avoid issues down the road.
07-31-2006, 08:21 AM
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No symptoms, just replaced based on the mechanic's recommendation....m..
What's interesting is that I received a letter from Audi of America about a service bulletin to fix a manifold hose at no charge, explaining that it may deteriorate and fail. It doesn't list the part number that needs to be replaced, so I'm going to try to find that out. It could possibly be the part I replaced. They say they'll reimburse someone if the part has already been replaced, so I'll make copies of my receipts and send them in. It's not expensive whether they refund my money or not.
Has anyone on the forum gotten a letter recently about it? I was on vacation last week, and so it was in my stack of mail when I returned. I didn't check AW while I was gone.
Has anyone on the forum gotten a letter recently about it? I was on vacation last week, and so it was in my stack of mail when I returned. I didn't check AW while I was gone.
07-31-2006, 08:32 AM
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My dealer replaced under warranty at last service (49K) without even asking...
They replaced the "L" hose that is known to fail as well. Nice to know there are some good dealers around...
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07-31-2006, 11:24 AM
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FYI, that hose (crankcase breather) will be replaced by Audi for free
on "some" 2002 A4 1.8T's up to 10yr/100k under an "emissions service action." I got a letter about it, and will be filing a reimbursement.
07-31-2006, 12:13 PM
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It's on the right hand side of the engine...do a search of the archives.
It looks more like an upside-down and flipped over L. Or like a 7 with a short horizontal line and long vertical one. There have been postings with pictures of others that have replaced it.