any guesses why my friend's GTI keeps blowing head gaskets?

[brainhulk]

He has the 2 liter MK6 GTI with a KO4 turbo. I believe he made 330 whp on the dyno. After a couple track days his mechanic found a blown head gasket. He proceeded to get forged rods and pistons and used a less agressive tune. Today he tells me his mechanic found another leak. I do not know how much less hp he was making. I asked him how high his AFR was set at and I believe he said something ~11 ish. We use 91 here in so cal, so I considered this to be cool. I remember my evo was tuned to about 350 whp and the afr went up to between 12-13 i believe. I never had problems with the engine beating it up at the track. Yeah it would overboost on colder days, but no overheating.

What I found peculiar is my friend's GTI used a lot less gas than my car at the track. I would go through 10 gallons in about 2 1/2 sessions (20 min sessions). While my friend would still be above half.

Any guesses why he keeps blowing head gaskets?

 

[JulesMaximus]

Maybe a slight warp or imperfection in the mating surfaces between the engine block and the cylinder head? Did he torque everything down properly when he replaced the head gasket last time?

 

[brainhulk]

Maybe a slight warp or imperfection in the mating surfaces between the engine block and the cylinder head? Did he torque everything down properly when he replaced the head gasket last time?

he didn't do the work himself. His mechanic works on a lot of tracked European cars though

 

[NutBucket]

I would guess a warped/cracked head as well. If all the mechanic did was replace the HG without a thorough inspection then it would make sense. However, you say this mechanic does a lot of built motors so that seems unlikely. Strange....

 

[Zivic]

he didn't do the work himself. His mechanic works on a lot of tracked European cars though

could be a lot of things.

improper mating surfaces - improperly machined, maybe just dirty when reassembled, warped components

improper head gasket....

head improperly torqued, maybe reusing TTY bolts? maybe need to re torque the studs after heat cycling.

bad tune.... small detonations eating away at the gasket

 

[JCH13]

If the head/block didn't get decked before the 1st replacement Hg went on... well... that's not so great.

Are the leaks recurring in the same place?

 

[AMCRambler]

What JCH said.

Could be a casting imperfection on the block or head if they both leaked at the same place. Maybe stock it was fine but with the mods pushing more power=more stress on that gasket.

Be interested to know what the old gaskets look like. Did they break or do they look fine?

 

[Rifter]

did they deck the head last time?

 

[brainhulk]

Thanks for the replies. Ill have to ask my buddy when he's feeling better. This car has been nothing but trouble for him. Sucks he'll miss our next track day, it's gonna be our first time going to chuckwalla raceway. He just bought some NT01's too.

 

[boomerang]

We could guess until the cows come home but if his mechanic can't figure it out he needs to find a new mechanic. It's just that simple.

 

[phucheneh]

Is the gasket VW or aftermarket? If the latter, is it made extra-thick to lower the compression ratio?

Are the head bolts torque-to-yield? You'll know if the tightening sequence ends with turning them a certain amount of degrees rather than to a specific torque measurement. If so, they're intended to be replaced; the torque is an angle rather than ftlb/Nm because the threads stretch during the final tightening, and the latter cannot be measured accurately.

There are plenty of other questions that can be asked, since it's modified. What's the compression ratio? How much boost? Factory ECM/programming? Does it have aftermarket head studs? If not...do other VW owners making similar power on that engine tend to recommend them?

 

[michal1980]

Thanks for the replies. Ill have to ask my buddy when he's feeling better. This car has been nothing but trouble for him. Sucks he'll miss our next track day, it's gonna be our first time going to chuckwalla raceway. He just bought some NT01's too.

its sucks for your friend. But blaming the car for not being reliable when pushing 50% more power? not really the cars fault

 

[manimal]

I'm half Asleep but I think the stock hg is pretty robust on mk6 Gtis. Does he have a catch can?

 

[brainhulk]

I'm half Asleep but I think the stock hg is pretty robust on mk6 Gtis. Does he have a catch can?

No catch can. He only has an aftermarket oil cooler.

 

[Vdubchaos]

its sucks for your friend. But blaming the car for not being reliable when pushing 50% more power? not really the cars fault

Well, I have a K04 on my Passat (actually had it on 2 passats) and I'm at 145k Miles. My 1st one had 140k when some lady hit me from the back and totalled it. Both were K04ed at about 75k miles.

But what he said above stands. VWs are not exactly reliable. This is coming from a guy that actually has had 2 reliable MODIFIED VWs. HOWEVER, being around VW Community for past 15 years (helping people work on cars and watching others) taught me a lot about these cars......and it's owners.

1st thing is first. How does OPs friend treat his car? Does he do burn outs/abuses it? Does he let it warm up/cool down? Does he maintain his car properly? VW scene is FILLED with complete idiots

2nd - which tuner has done the work/modified it? Tuner shops have VERY little incentive for reliability on your car. Heck most of their income is from Service repairs. Mark my words, there is VERY few good VW Tuners out there.

Where did the mechanic find another leak? Did he notice it before he brought it to the shop.

The reason why your friends car uses less gas is most likely dues to # of things:
- Less weight
- Direct Injection
- Less Power

One of the lessons I have learned (this doesn't just apply to cars either) is unless you do the shit yourself, it will never be done to your standards.



I suggest that your friends gets a 2nd opinion or gets to the bottom of what's wrong himself.

Thanks for the replies. Ill have to ask my buddy when he's feeling better. This car has been nothing but trouble for him.

All too often (but not always) this is the story of your average German car owner (from what I have seen).

 

[Jimzz]

Maybe the person who did the work did not send the head out to a machines shop and its got some high/low spots?
Could be the block as well but usually in the head.

Or as said he is making to much power for the OE style head gasket.

 

[JCH13]

I'm half Asleep but I think the stock hg is pretty robust on mk6 Gtis. Does he have a catch can?

No catch can. He only has an aftermarket oil cooler.

Hooray knock potential! :\

 

[manimal]

tell him to get a bsh recirculating catch for TSI engines.


Some peeps swear by catch cans for DI engines and some VW vortex guys will say their catch hasnt filled in a year. Does you buddy have a build log on any sites>?


ask him if hes bypassed the pcv to the exhaust?

 

[PhoKingGuy]

All too often (but not always) this is the story of your average German car owner (from what I have seen).

Hey everyone, its this idiot again.

 

[PlasmaBomb]

its sucks for your friend. But blaming the car for not being reliable when pushing 50% more power? not really the cars fault

Aren't mk6 GTIs ~180 WBHP stock? or are US versions higher?

If so 330 WBHP is a damn sight more than 50%...

 

[michal1980]

Aren't mk6 GTIs ~180 WBHP stock? or are US versions higher?

If so 330 WBHP is a damn sight more than 50%...

I missed the W,

yes you are right its much higher then 50%. + track = exploding engines. VW or not, odd's are a large number of engines would fail the reliability test with that much power

 

[Ferzerp]

wbhp? Errr. "Wheel brake horsepower"? That's meaningless.

 

[brainhulk]

tell him to get a bsh recirculating catch for TSI engines.


Y peeps swear by catch cans for DI engines and some VW vortex guys will say their catch hasnt filled in a year. Does you buddy have a build log on any sites>?


ask him if hes bypassed the pcv to the exhaust?

his build threads:

http://golfmk6.com/forums/showthread.php?t=20959

http://golfmk6.com/forums/showthread.php?t=31742

He just told me his mechanic thinks his tune has his timing set too aggressively leading to hot cylinder temps.

 

[phucheneh]

wbhp? Errr. "Wheel brake horsepower"? That's meaningless.

That'd be an interesting dyno setup.

I think we're all just assuming he had the car on a roller dyno.

 

[brainhulk]

I think he's moving on from his toy. He told me he's trying to get a b8 s4 or m3