Warped Intake Manifold?

[smith6]

Sorry if this is a silly question but is it possible to warp your intake manifold and cause vacuum leak?

Backstory…i’ve been consistently getting CEL for lean at idle so i took it to a Euro mechanic to do a vacuum test. They told me that the intake manifold is warped causing the vacuum leak. They explained that the previous shop who installed the spacer didn’t put the manifold back together correctly causing it to get warped / damaged. They also told me the cost to replace is more that 1/2 of what the car is currently worth… this part i believe, the rest i’m not so sure.

is this possible or can the leak be fixed by replacing the manifold gasket?

[2008_S6]

Answer: yes. I had a warped manifold that leaked at the corners. I verified by sealing all openings in the manifold and then pressurizing at low pressure (sorry, cannot remember exact pressure…maybe 10 psi?). Used blocked off PVC pipe where the TBs are. Sprayed soapy water and it bubbled at two of the four corners.

To be clear, I’m talking about a leak between the IM halves. You can use the same technique though.

[smith6]

Thanks for the reply, I was sooo hoping for a different response though. So I guess I’ll be riding with a CEL for a while until I can afford a new manifold and the labor to install it. Just curious how did you remedy your manifold?

[Mr.twooooo]

New manifolds certainly aren’t cheap. But in my opinion taking the manifold off and replacing it is an easy job. There are step by step guides On the forum for how to take it off. Read up on it and get familiar with the process and it will save you quite a bit of money.
I’ve had my intake off about 4 times now for various reasons. Last time I think it took me about an hour from getting the tools I needed to the intake being off.

[justincredible]

Well maybe this is some possible good news.

While its possible to warp an intake its incredibly hard. If a shop bolts down the intake in an incorrect pattern that can and will cause a possible warp condition. NOW the good news. If the intake warped you can always Tq it back down and get it back into its proper shape.

Here is a generic bolt tightening pattern. Just keep in mind your starting in the middle and working your way out to the edges. Also you only want to tighten the bolts that go into the head. this picture is just showing you a reference .

Now keep in mind two down sides. If your intake is crazy warped you can crack it tightening it back down. But if the intake is warm it’s less likely to crack or have any issues.

Last thing. If your intake is leaking at the seems. Then you would need to take the intake apart and seal it with some RTV. So in the end. I wouldn’t go out and get a new intake just yet. Find out where the leak is at and see if you can tighten and inspect that part of the intake.

[Kimovitzh]

From the Audi workshop manual

[smith6]

Wow thanks for the info, this has given me some hope and taken me from a possible $5K job to potentially a free fix after putting in some elbow grease, sore back and cut knuckles.
I have to admit pulling the intake off has been very intimidating to me because i fear i’d mess up and damage the motor… however considering the alternative cost and the benefits of a carbon clean and checking on the condition of prior o-ring replacements, it’s worth a shot.

Assuming there are also some cracked hoses mixed in any suggestion on the most effective way to do a DIY vacuum leak test at home?

Thanks again for the feedback it is much appreciated.