Head Gasket can of worms??? - Now chasing Boost Leaks!!!

[Fat Audi 80]

Thanks, I am now going to test again when the new parts arrive....

[newsh]

Hi all,

Bloody hell this is dragging on isn't it! Well since I last posted the car has passed another MOT (with boost leak) and I have moved house.

After multiple attempts to pressurise the intake system with a tyre compressor I bit the bullet and ordered a full Boost Leak testing kit:

https://www.amazon.co.uk/System-Leak.../dp/B0C3BLD4D7

and a proper garage compressor:

https://www.sgs-engineering.com/sc6h...air-compressor

Why did I wait so long to do this??!!

Leaks can be found almost instantly which were:

1. 90 Rubber hose at the rear of the cam cover (it has split under the hose clip)
2. The small rubber bellows that houses the one way valve under the throttle body

I have a new silcon version of 2. on order and will hopefully have the S2 back to full turbo boosting glory soon......


Lesson: Buy the right bloody tools!

Good move

When you've fixed the big leaks, test again, and find the small ones

[Fat Audi 80]

Hi all,

Bloody hell this is dragging on isn't it! Well since I last posted the car has passed another MOT (with boost leak) and I have moved house.

After multiple attempts to pressurise the intake system with a tyre compressor I bit the bullet and ordered a full Boost Leak testing kit:

https://www.amazon.co.uk/System-Leak.../dp/B0C3BLD4D7

and a proper garage compressor:

https://www.sgs-engineering.com/sc6h...air-compressor

Why did I wait so long to do this??!!

Leaks can be found almost instantly which were:

1. 90 Rubber hose at the rear of the cam cover (it has split under the hose clip)
2. The small rubber bellows that houses the one way valve under the throttle body

I have a new silcon version of 2. on order and will hopefully have the S2 back to full turbo boosting glory soon......


Lesson: Buy the right bloody tools!

[Fat Audi 80]

Have you ever changed the plastic one way valve in the pipe work off the underside of the inlet manifold Steve?
I’d advise everyone to change this if it’s still the original.
I was chasing a boost leak or a long time, then it developed an oil leak from the front cam seal, which turned out to be this valve leaking when on boost, pressurising the breather system and the top of the head and leaking past the seal.
Changed the valve and got nearly all the boost back and no more leak.

Nope! One has been ordered.

Thank you!

Cheers

Steve

[psiconauta911]

Thank you!

[martinjs]

035103245A

No20 in this picture, it goes inside the rubber pipes

78C6A0EA-7A85-4B4A-8F1D-9BCCFFFC4DE1.png

[psiconauta911]

Have you ever changed the plastic one way valve in the pipe work off the underside of the inlet manifold Steve?
I’d advise everyone to change this if it’s still the original.
I was chasing a boost leak or a long time, then it developed an oil leak from the front cam seal, which turned out to be this valve leaking when on boost, pressurising the breather system and the top of the head and leaking past the seal.
Changed the valve and got nearly all the boost back and no more leak.

Hi, can you give us the part nº for this valve? Thank you.

If you could post a picture from Etka with the precise piece and location it would be great.

[martinjs]

Have you ever changed the plastic one way valve in the pipe work off the underside of the inlet manifold Steve?
I’d advise everyone to change this if it’s still the original.
I was chasing a boost leak or a long time, then it developed an oil leak from the front cam seal, which turned out to be this valve leaking when on boost, pressurising the breather system and the top of the head and leaking past the seal.
Changed the valve and got nearly all the boost back and no more leak.

[Fat Audi 80]

Hi mate
Stick with it, you’ll get there.

Firstly I would test with the PCV system completely disconnected.
The pipes from the crankcase vent to the cam cover and MAF hose only ever see vacuum so pull the 20mm pipe out of the MAF hose and plug the hole in the MAF hose.

You should be able to pump it up to 1Bar and it goes down slowly for 20-30 seconds.

Some air will escape past the rings into the sump.
Check around the injector seals. (Not sure if you fitted new ones)
Hoses to and from ISV.
WG diaphragm (air from top chamber).
WG valve guide (air escaping into exhaust).
To isolate WG disconnect it’s hose and plug it.
Air leaking at WGFV (I’ve seen a few of these)
To test the DV you have to disconnect its vac line from the nipple at the front of the manifold, then listen to the line and block the nipple with your finger. If the DV diaphragm is split then air will come out of the hose.

Just a thought, have you got a boost gauge on the car? If so what’s it actually boosting to when you drive it?? Full throttle at 3k5 in 3rd?

Is the vac/boost line to the MAP sensor in the ECU connected?

Oh yeah. There’s also a vac line under the rear seat for the diff lock which can split or come disconnected. Usually hear that when driving though!

If you want to discuss anything on the phone PM me your number and I’ll get back to you.

Thanks John, great advice. Let me try and have another go at the weekend. I have started to try and understand the various Sub systems that can be isolated via the excellent sticky on this, As trying to diagnose leaks over the entire system seemed impossible...

I appreciate the offer of a voice on the end of the phone too and will let you know....

Thanks

[newsh]

Hi mate
Stick with it, you’ll get there.

Firstly I would test with the PCV system completely disconnected.
The pipes from the crankcase vent to the cam cover and MAF hose only ever see vacuum so pull the 20mm pipe out of the MAF hose and plug the hole in the MAF hose.

You should be able to pump it up to 1Bar and it goes down slowly for 20-30 seconds.

Some air will escape past the rings into the sump.
Check around the injector seals. (Not sure if you fitted new ones)
Hoses to and from ISV.
WG diaphragm (air from top chamber).
WG valve guide (air escaping into exhaust).
To isolate WG disconnect it’s hose and plug it.
Air leaking at WGFV (I’ve seen a few of these)
To test the DV you have to disconnect its vac line from the nipple at the front of the manifold, then listen to the line and block the nipple with your finger. If the DV diaphragm is split then air will come out of the hose.

Just a thought, have you got a boost gauge on the car? If so what’s it actually boosting to when you drive it?? Full throttle at 3k5 in 3rd?

Is the vac/boost line to the MAP sensor in the ECU connected?

Oh yeah. There’s also a vac line under the rear seat for the diff lock which can split or come disconnected. Usually hear that when driving though!

If you want to discuss anything on the phone PM me your number and I’ll get back to you.

[Fat Audi 80]

Well I spent most of Saturday chasing more boost leaks! The intercooler one appears to have been successfully patched up.
I then found another one on the ISV, this was successfully sealed with clear epoxy.

My compressor will now pressurise to approx 6 psi (it was 3 psi before) so there is some progress, but I cannot get it to go any higher. Air is escaping somewhere and I cannot see or hear it!

To cut a long story short I have taken off and visually checked every single rubber hose in the intake / turbo and camcover breather system - all ok. (this took bloody hours) I have pressurised the system again and again and sprayed soapy water everywhere and cannot see or hear any leaks. All small diameter hoses have been replaced with brand new silicon hose. All jubilee clips are new etc...

I have driven the car and although it is better and will boost to 6k rpm in second, as the load increases and you go up through the gears you can feel the boost bleeding away somewhere. The car has 75% of its true performance.

Any ideas as to what to try next?!

Thanks,

Steve

[Fat Audi 80]

Once I get the boost leaks fixed it will be mega. I think it has had some leaks for a number of years, started to feel "flatter" about 4 years ago!

[Fat Audi 80]

Thanks John, that was my thought process. Nothing to lose really.

[newsh]

Second leak found. Right in the middle of the intercooler. Has anyone any experience of trying to fix this with JBWeld or equivalent?!

(I have already had a dig around the fins to try and find it and white stuff is washing up liquid!)

Thoughts?

Intercooler small.jpg

******!

Yes.

Clear away the crinkly stuff around the leak, make sure you’ve definitely found the leak.
Clean it really well, rough it up with coarse wet&dry, clean again with alcohol or brake cleaner and stick a blob of JB Weld on it. Should last for years.

[Fat Audi 80]

Second leak found. Right in the middle of the intercooler. Has anyone any experience of trying to fix this with JBWeld or equivalent?!

(I have already had a dig around the fins to try and find it and white stuff is washing up liquid!)

Thoughts?

Intercooler small.jpg