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Discussion Starter #1
Hey guys. 04 1.8t. I replaced my head gasket, again, about 1500 miles ago. No overheating during that time. I changed my oil yesterday and noticed a small amount of milkshake on my oil cap, but no noticeable watet in the oil. I had trouble starting it shortly after, and checked the dipstick. LOTS of milkshake. Last time it blew a gasket, I had several days of driving left before it got this bad. This Time, it only took a few miles of driving..... IDK WTH im doing wrong. Cleaned the block. Shaved the head. Not seeing any cracks in the head. 30ft.lbs of torque from center out, followed by two more steps of 90° turns for 180° total. Ive seen a few guys saying that you should tighten until it stretches, then back off a quarter turn, whatever that means, but I have not done this procedure in the past. Please help before i put my THIRD head gasket on. In the past, the car overheated, but not this time, and its really throwing my for a loop. Thanks.
 

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There could be a crack in the block or inside the oil cooler. The block could be warped, but that's pretty rare. I would start with the oil cooler, but most of the time, it ends up pumping oil into the coolant as the oil pressure is higher.
Have you tested the cooling system for leakdown? Was the head tested?
 

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PZ makes good points to check out.

Other things to think about.
Are you re-using the same head bolts? Those head bolts are ONE TIME USE ONLY. With all of the torque applied to those things, they stretch, considerably.
Don't ever back off on a head bolt. You torque it down and leave it.

I've had numerous heads off my Passat's and I have learned a few things.

1) DO NOT use the cheap head bolts. For instance right now on ECS Tuning you can buy a set of head bolts for $20. Mark my words, those will cause you trouble in the long run. The steel used is not of the same quality as the Genuine VW/Audi. The cheap head bolts stretch at different rates between each of the bolts. Matter of fact, When I rebuilt my wife's 2003 GLX V6, I had one bolt that never torqued, it just kept stretching! Lesson learned the hard way.

2) I'm going to get some serious flack here, but I stand by what I say. I DO NOT follow the torque procedure set forth in the Bentley Manual. I follow the tightening pattern, but I torque all the bolts to 30ft lbs, then 60ft lbs, and then 90ft lbs. I then let the head sit for about and hour and re-torque to 90 ft lbs. After the engine has been all assembled and ran for a few hours I go back and re-torque to 90ft lbs. Yes, it is a labor intensive procedure but I've never had a problem with doing it this way.

3) Use a high quality head gasket. Going cheap here may result in failure. Not saying it will, but why even risk it considering the work involved changing it if it does fail.


I noticed the whole surface of the block (the deck) is black. For a head gasket that new, it shouldn't look like that. Something is wrong.

Per the Bentley Manual the MAXIMUM allowed head warpage is .1mm (.0004 inch). That is a very small amount. You need to check with an indicator to make sure it is within spec, if not, have the head milled.
The engine block head deck surface must be absolutely clean before installing a new head gasket. Absolutely no ridges of carbon build-up allowed.
 

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Here's my wife's V6 engine rebuild.

Picture is a bit blurry, but notice the head deck, it's pristine. Genuine VW/Audi head gasket.

99493



Genuine VW/Audi head bolts. About $140 per set (per bank) on a V6.

99494
 
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Discussion Starter #6
PZ makes good points to check out.

Other things to think about.
Are you re-using the same head bolts? Those head bolts are ONE TIME USE ONLY. With all of the torque applied to those things, they stretch, considerably.
Don't ever back off on a head bolt. You torque it down and leave it.

I've had numerous heads off my Passat's and I have learned a few things.

1) DO NOT use the cheap head bolts. For instance right now on ECS Tuning you can buy a set of head bolts for $20. Mark my words, those will cause you trouble in the long run. The steel used is not of the same quality as the Genuine VW/Audi. The cheap head bolts stretch at different rates between each of the bolts. Matter of fact, When I rebuilt my wife's 2003 GLX V6, I had one bolt that never torqued, it just kept stretching! Lesson learned the hard way.

2) I'm going to get some serious flack here, but I stand by what I say. I DO NOT follow the torque procedure set forth in the Bentley Manual. I follow the tightening pattern, but I torque all the bolts to 30ft lbs, then 60ft lbs, and then 90ft lbs. I then let the head sit for about and hour and re-torque to 90 ft lbs. After the engine has been all assembled and ran for a few hours I go back and re-torque to 90ft lbs. Yes, it is a labor intensive procedure but I've never had a problem with doing it this way.

3) Use a high quality head gasket. Going cheap here may result in failure. Not saying it will, but why even risk it considering the work involved changing it if it does fail.


I noticed the whole surface of the block (the deck) is black. For a head gasket that new, it shouldn't look like that. Something is wrong.

Per the Bentley Manual the MAXIMUM allowed head warpage is .1mm (.0004 inch). That is a very small amount. You need to check with an indicator to make sure it is within spec, if not, have the head milled.
The engine block head deck surface must be absolutely clean before installing a new head gasket. Absolutely no ridges of carbon build-up allowed.
Yes, I always use new bolts. The bolts and gasket were Felpro, from Advanced Auto....
The carbon buildup on the block has been there since I changed the first one. I scraped as best as I could without scoring it, but I will see what i can do this time... The head was resurfaced the past two times I replaced the gasket. Im taking it to the shop this morning to check for cracks and if its warped. It was driven less than 2000 miles this past round, and never overheated, so it should be fine... I will follow your method of tourquing down the head this time around... Thanks for yhe detailed info. I'll be back on here after I get some more info.
 

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Discussion Starter #7
Yes, I always use new bolts. The bolts and gasket were Felpro, from Advanced Auto....
The carbon buildup on the block has been there since I changed the first one. I scraped as best as I could without scoring it, but I will see what i can do this time... The head was resurfaced the past two times I replaced the gasket. Im taking it to the shop this morning to check for cracks and if its warped. It was driven less than 2000 miles this past round, and never overheated, so it should be fine... I will follow your method of tourquing down the head this time around... Thanks for yhe detailed info. I'll be back on here after I get some more info.
 

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Well it certainly looks cleaner, however, my personal opinion is that it's still not good enough. I can see lines and pitting in the surface of the block.

If it were my engine I would not assemble in that condition. At the very least I would pull those (2) dowel pins out and stone the surface of the block with high a quality stone.
It would take a while to prep the surface but it can be done. I've done that before, a number of times. It's a poor mans way of resurfacing a block.
I use round rubber stoppers (available at your local science & surplus) to plug the cylinder bores to keep all the grit from the stone getting down into the piston area between the cylinder wall and upper compression ring. After finished stoning the surface of the block I use a shop vac to suck out all the grit and garbage.

Now again, if it were me, at this point I would just yank the motor and have the block head surface ground.
But then again, I've been known to pull motors just because. Well documented here in this forum.

I know I might be the bearer of something you may not want hear, but me being a machinist dictates what is good and bad when it comes to metallic surfaces that require mating.
 
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Seeing as I can't edit my post. (#4 in this thread)

This statement is wrong. Thanks to Chief. ;)
Per the Bentley Manual the MAXIMUM allowed head warpage is .1mm (.0004 inch).

That should be 0.01mm (.0004 inch)

:cool:
 
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PZ makes good points to check out.

Other things to think about.
Are you re-using the same head bolts? Those head bolts are ONE TIME USE ONLY. With all of the torque applied to those things, they stretch, considerably.
Don't ever back off on a head bolt. You torque it down and leave it.

I've had numerous heads off my Passat's and I have learned a few things.

1) DO NOT use the cheap head bolts. For instance right now on ECS Tuning you can buy a set of head bolts for $20. Mark my words, those will cause you trouble in the long run. The steel used is not of the same quality as the Genuine VW/Audi. The cheap head bolts stretch at different rates between each of the bolts. Matter of fact, When I rebuilt my wife's 2003 GLX V6, I had one bolt that never torqued, it just kept stretching! Lesson learned the hard way.

2) I'm going to get some serious flack here, but I stand by what I say. I DO NOT follow the torque procedure set forth in the Bentley Manual. I follow the tightening pattern, but I torque all the bolts to 30ft lbs, then 60ft lbs, and then 90ft lbs. I then let the head sit for about and hour and re-torque to 90 ft lbs. After the engine has been all assembled and ran for a few hours I go back and re-torque to 90ft lbs. Yes, it is a labor intensive procedure but I've never had a problem with doing it this way.
I won’t give you FliegerAbwehrKanone, but 90 ft-lbs is too little to stretch the bolts and give you the clamping force of 2 x 90°

It apparently works but it’s “rogue”
 

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Discussion Starter #11
I won’t give you FliegerAbwehrKanone, but 90 ft-lbs is too little to stretch the bolts and give you the clamping force of 2 x 90°

It apparently works but it’s “rogue”
Yeah, I did 30lbs and two more 90° turns, and I wasnt even close to 90lbs. So, I torqued it a third 90° after I warmed up the motor and left it alone. It still wasnt hitting 90lbs. I was concerned about over stretching, just as you are.
 

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Yeah, I did 30lbs and two more 90° turns, and I wasnt even close to 90lbs. So, I torqued it a third 90° after I warmed up the motor and left it alone. It still wasnt hitting 90lbs. I was concerned about over stretching, just as you are.
Oh wait, you said too little?
 

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I won’t give you FliegerAbwehrKanone, but 90 ft-lbs is too little to stretch the bolts and give you the clamping force of 2 x 90°

It apparently works but it’s “rogue”
Call it rogue if you want but there is actually some method to my madness here.

For starters, the assembly of our Passat engines (and most others for that matter) happens in a production factory where pretty much everything is in a 'controlled' environment.
Torqueing of the cylinder heads is done by a gang head which torques all of the bolts to exacting specifications automatically. Along with that the threads in the engine block and head bolts are prepped with just the right amount of lubrication to obtain consistent torque values and to keep the threads from getting galled or stripped.

There is no way in the world I can duplicate those controlled environment parameters in my garage.
Straight up, I am in no way a be all expert, however I've built enough engines that I know what I'm talking about. I'm pretty sure others here will agree.
The 35 years of machining and 20+ years of mechanical design I have under my belt also plays into the knowledge I have on how all this stuff works.

Simple comparisons can be made here.

Pretty much any old 50’s, 60’s and 70’s engines all shapes and sizes get a head bolt torque value of 80ft lbs to 110ft lbs no matter what the compression ratio, horsepower or the cubic inch size of the motor is.
A Passat engine is hardly anything more than what it used to be from back in the day, as far as a basic functionality / principal goes.
With all that being said, the head bolts that are on a V6 and 1.8 are of 11mm diameter. Very rough calculations with that bolt torqued to 90ft lbs, the clamping force is approx. 12,555 lbs.
That kind of pressure or force will be more than sufficient to seal up the head gasket.

The engineering factor of all this is the fact that the head is made of aluminum. With the distance between each of the head bolts the aluminum isn’t strong or rigid enough to stay completely flat. To understand what I mean, take a piece of cardboard, lay it on a table, use your index finger and your thumb spread apart, push down as hard as you can. What happens? The cardboard directly under your fingers gets mashed right to the table, the area between your fingers stays relatively uncompressed.
The exact same thing happens with a cylinder head that gets bolted down to an engine block.

With that analogy, that is why the mating surfaces of the block and the head are so critical.

So, do I follow the Bentley Manual on this procedure? No I don’t. But any experienced engine builder will back me up on this. Torqueing a bolt to known value is way more accurate than just twisting a bolt a certain number of turns.
 
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Just out of curiosity, what type of torque wrench are you using? 30 lb/ft tends to be at the minimum or maximum of a lot of torque wrenches where the the accuracy is not the greatest.
 

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Snap-On brand click type torque wrench and an old style Craftsman beam type (from the 50's) are what's in my toolbox.
 

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Discussion Starter #16
I give up. For now. 50 miles and ive got milkshake again. Im parking it until I get answers. Its not so much the cost, as it is my time. I refuse to except defeat though...
 

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Ok. Im feeling like I may have made a rookie mistake here. I didnt clean out the thread holes in the block. Im positive there was water in some of them and possibly oil as well. I'm pretty sure I would not be able to get an accurate torque reading, in this scenario. It would explain why the bolts didnt feel as tight as they should be after completing the factory procedure steps. Am I correct??? Also, is it possble to over lubricate the bolts.? I dipped them in fresh oil and immediately put them in the hole...
 

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Yes, that might cause a problem. Worst case scenario, hydraulic pressure from screwing a bolt into a fluid-filled hole can crack the head. I've never needed to replace a 1.8T head gasket (not a common failure) but on other engines you make sure the hole is clean and dry, and wipe the threads with a minimal amount of oil.
 

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Let’s get back on track. The question is whether you have a failed head gasket or some other leak. I would check with a tester before assuming.

I had the head checked and resurfaced the first time I had to replace a gasket. That gasket lasted about 2000miles. I just put the third one on and got 50 miles out of it. I'm 90% sure its something I'm doing.
 
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