# Possible blown head gasket or...??



## velocitychris (Jul 16, 2011)

Hi all. Have a new issue with the TT225. Was doing a little track lapping on Friday. After 2 sets of 6 laps I came hard into the final turn before the straight, shifted 3>2, and when I hit the WOT, the whole car shuddered and I initially thought I mis-shifted into 4 instead of 2. And I found myself limping down the fast straight in 2. We got it off track turned it all off and pushed it into the pits (it was close). 

We popped a number of fault codes:
16685 - Cyl 1 misfire
16686 - Cyl 2 misfire
16684 - random/multiple misfires
16712 - knock sensor 1 - g61 - signal too high - intermittent
17743 - engine torque monitor 2 - p1335-35-10 - control limit exceeded intermittent
16487 - MAF - signal too high intermittent
17832 - secondary air injection - leak detected
18010 - power supply terminal 20 - p1602 - voltage too low
----
17544 - fuel trim bank 1 - p1136 system too lean
(this one had popped up earlier)

After resetting everything, we were still getting the cylinder 1&2 misfires.

We switched coil packs 1 & 2 with 4 & 3 (went 1,2,3,4 to 4,3,2,1) and still have misfires on cylinder 1&2. Boo.

I noticed a little bit of oil on that upper ridge of the head ABOVE the intake manifold. I had the intake manifold off 2 weeks ago doing a PCV refresh. Possibly had not tightened bolts on intake mani tight enough?

My brother - who I bought the car with to be a project car, AND who is smarter at this than I am - is initially thinking that it might be a blown head gasket. Although this is uncommon, based on the searching, there is a reason behind this thinking. Last year we had the head replaced (not by us, but a shop) and so possibly an error was made on install.

Saw a couple of relevant posts:
http://forums.subdriven.com/showthread.php?5620125-Misfire-on-1.8t-cylinder-3

http://forums.audiworld.com/showthread.php?t=2803873

We are going to try to do a compression test and leak down test, and will check the oil. 

Wanted to check and see if anyone has any other suggestions based on this info. One of my similar searches had someone suggesting a faulty harness (the current one is original), which they replaced but was not the case and turned out to be a blown head gasket.

Thanks, 
Chris


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## Audiguy84 (Nov 14, 2006)

I really don't think its a blown head gasket, these 1.8T's are stout in that department. Did you pull the spark plugs to see what they look like? Also check injectors to see if their working correctly.


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## codewhore (Oct 22, 2006)

Hey Audiguy84, I'm Chris' brother Shawn. I pulled plugs 1 and 4 and both looked basically the same. I also as best as I could looked down into the cylinders and again they looked about the same. However the engine wasn't running more than 1 minute after the loss of power.

We have not checked the injectors directly yet but now that the car is back in the garage we can begin further testing/diagnosis.


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## velocitychris (Jul 16, 2011)

Today we did a cylinder test but knew we were in trouble as soon as we pulled the spark plug. Looking into cylinder 2 revealed an ugly bottom (see pic). Sure enough, the compression test yielded cylinders 1, 3 and 4 as fine and consistent, with no pressure at all in cylinder 2. 

I guess that we now start the process of figuring what exactly has broken here. Pulling apart the head is new territory for me (last year we had a shop do it). Should be an adventure! We did the timing belt last year, so have been around in there a bit. Does anyone have any pointers to make it an easier job? Does the timing belt have to be completely rethreaded or just the upper portion removed? Any easy way to get the tensioner released and reset? I'll be searching all of this, but looking for any tips.










Here is the oil splatter I mentioned - the head on left, fuel rail on right and splatter on the vacuum lines.


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## velocitychris (Jul 16, 2011)

I wonder if it could be a broken connecting rod or anything like that? Going to maybe crank the engine manually to see if there is movement on piston #2.


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## lite1979 (Sep 9, 2005)

I would try a leak-down test to see where the air's escaping to. I'd rather it be a head problem than a bad connecting rod for your sake. Why was the head replaced to begin with?


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## codewhore (Oct 22, 2006)

Manually rotating the engine all the pistons where moving so that should rule out the busted rod. Leak down test raised more questions than answers but for the record this is the first time either of us ever had to do these sorts of tests so...

What we found is the leak down test on cylinder 3 and 4 was no leaks, as expected/hoped. 

Cylinder 2 had a massive leak and appeared to be coming out of the charge pipe at the back of the engine as well and into the other cylinders. Admittedly we found in further testing on the other cylinders that even a hair off TDC the valves would be opening and might have skewed our perception.

Cylinder 1 had a small leak and only could be heard from the charge pipe. And this is the part that is totally confusing me and need some help understanding.

The timing belt appears to still be fine (i.e. has not skipped a tooth) so if it were a problem with the head and only affecting cylinders 1 and 2 what could have happened?

As for last year and the head replacement, we attempted a full timing belt change and during the install the belt slipped off. In rotating the crank and cam to get back to TDC I basically forced the valves on #1 cylinder into the top of the piston and tweaked it enough to bend it and lose compression (lesson learned). We don't have any local shop that we trust to rebuild the head so we bought a complete replacement and had it installed by an independent Audi shop.


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## lite1979 (Sep 9, 2005)

Do all four cylinders peak at the same height? Even when you bend a connecting rod, you can still turn the crank. Check your timing belt tensioner and cam chain tensioner as well. This head may have had a tensioner on the way out, or poor oil flow to the head.


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## codewhore (Oct 22, 2006)

I will run the next set of tests on Saturday as that is the next time I am likely going to be seeing the car.


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## Audiguy84 (Nov 14, 2006)

you sir floated a valve(s), the same thing in the same cylinder happened to my car. You did say it happened when you down shifted 3 to 2.... mechanically over reved the engine..

If you want to you can tear it apart but your going to need a new engine.


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## truman77 (Feb 14, 2007)

Audiguy84 said:


> you sir floated a valve(s), the same thing in the same cylinder happened to my car. You did say it happened when you down shifted 3 to 2.... mechanically over reved the engine..
> 
> If you want to you can tear it apart but your going to need a new engine.


why would he need a new engine?


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## Audiguy84 (Nov 14, 2006)

When the piston eats the valve it most likely broke the valve head off and also broke more then one valve. That valve head is now bouncing around in the chamber mashing up the head, piston, and side walls. Now when it happened to my engine the side walls weren't that bad but some of the marking were deep enough that boring the block wasn't possible


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## 18T_BT (Sep 15, 2005)

This was my engine. I can't tell you about any codes it threw because I got it this way with a dead battery.

http://i856.photobucket.com/albums/ab126/kilmer420/IMAG0146_zps870c1200.jpg
http://i856.photobucket.com/albums/ab126/kilmer420/IMAG0144_zps5ffb5ca9.jpg


Pulling the head is pretty straight forward. You will need a new headgasket, tensioner, roller (i guess you can re-use the roller) and head bolts (at this point I suggest you invest in some ARP's because factory bolts are like 30 bucks, but if you ever do it again, might as well have re-usable ones. Up to you of course, you'd have to pull the head like 3 times to make it worth your while: http://lightningmotorsports.com/i-445388.aspx?gclid=COTg9bz53LcCFQLxOgodzmYACA (Don't forget the head removal tool which you can pick up at Autozone/Carquest etc) If your changed your belt recently, you can re-use it of course. It's very similar to doing a timing belt except you remove the turbo (you can keep the manifold attached to the head) and you don't mess with the dreaded engine mount fanangling 

GL :thumbup:


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## codewhore (Oct 22, 2006)

18T_BT said:


> This was my engine. I can't tell you about any codes it threw because I got it this way with a dead battery.
> 
> http://i856.photobucket.com/albums/ab126/kilmer420/IMAG0146_zps870c1200.jpg
> http://i856.photobucket.com/albums/ab126/kilmer420/IMAG0144_zps5ffb5ca9.jpg
> ...


Wow that is really nasty. So far we can't see that kind of damage looking into the cylinder through the spark plug hole but there is some black/brown goo in there, presumably oil and/or coolant mixed with the carbon build up.


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## velocitychris (Jul 16, 2011)

Audiguy84 said:


> When the piston eats the valve it most likely broke the valve head off and also broke more then one valve. That valve head is now bouncing around in the chamber mashing up the head, piston, and side walls. Now when it happened to my engine the side walls weren't that bad but some of the marking were deep enough that boring the block wasn't possible


Ding!
Initially I was discounting this as I actually did a 4>3>2 shift and I really don't remember it spiking that high, but we have proof.
Finally got it all apart today and, yes - piston mashed against the valve. Surprisingly, while the valve had mashed into cylinder 2 piston, nothing had fully separated. The cylinders all look fine, actually. Surprised. All the pistons have markings on the exhaust side that show contact. 

So right now I am enjoying a drink as I contemplate the next move. I would like to do an Integrated Engineering stroker kit but I do not really have the funds for that at the moment. I guess I can ship the head off to 034 to have it serviced with new valves put in. I'd love to be able to drop a few thousand on some upgrades, but that is not in the cards. Despite this, are there any reasonable suggestions for parts?


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## velocitychris (Jul 16, 2011)

Damn! and now I have just read this thread:
http://forums.fourtitude.com/showth...ng-for-help-pushing-me-in-the-right-direction!

and it has got me thinking that I should really, really try to make the stroker kit work out. Similar to that thread's OP, I am still learning, but I am mostly interested in getting the engine peppy and torquey, not going to a big turbo, and, based on this experience, giving me some room when I am doing idiotic downshifting! 

Suggestions?


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