head gasket - leaking again 1.6TD

[joe1975]

Help :cry:

After replacing the head gasket it still leaks :x

Back ground
The engine is a 1.6TD in a Vanagon.  A while back we noted it losing water and traced it to the head gasket.  It was leaking on the injector pump side and around the back.  I could see a dribble of water.  This did not seem to make any difference to the running of the vanagon, and there was no trace of water in the oil.

The Diagnosis
We had the engine compression tested and it came back really good (the engine is a reconditioned with 20´000miles on it).  The one thing that was pointed out was that the turbo was not working, which would explain the lack of power.  We always felt it silly slow and hoped after the rebuild and a good tune up it would be usable again.

The repairs
I decided to fix it myself.  This was going to be hard as I had never worked on one of these engines before, all my knowledge was on the earlier aircooled vw engines.   I read and read about how to do it on different forums plus bought the Bentley manual.
I removed the head, and had it skimmed.  I then measured the piston projection and worked out from the Bentley manual that i needed a one notch head gasket (it had a 3 notch in it.)  I bought a good quality head gasket http://www.brickwerks.co.uk/index.php?page=shop.product_details&flypage=shop.flypage&product_id=538&category_id=89&manufacturer_id=0&option=com_virtuemart&Itemid=6
I then replaced the head bolts with new ones and torqued them down in the way the Bentley explained.  It did feel as if the last 1/4 turn was way to much and it could snap the head bolts but I think they where tight enough.  But maybe not?

I just had it running for the first time in months and it is leaking again from the same place but this time even worse as I noticed it only after 5mins of running.

What have I done wrong - Or what is wrong with my engine?  

Any help and advice would be great as i am a little gutted ...
 

[Riverfurm]

Same problem..... after three head gaskets and one head, found the block cracked. It was cracked from the right front head bolt hole. The leak would appear around the injector pump bracket and track down the back of the engine. I have picture I could Email you.

[SMOKEYDUB]

You should always follow exactly what the bently says. I know it feels scary the last 1\4 turn but alot of r&d went into that method and it works excellent. Alot of people mis-diagnose headgaskets and alot of the time its the coolant flanges on the cyl head seeps down collects on the headgasket and follows it around back of the cyl head looking exactly like a headgasket leak. Best way to figure it out is clean the engine really well blow of all the coolant areas and pressurize the system.

[joe1975]

I did follow the Bentley but it felt as if the last 1/4 was going to snap something.  It made me think that my torque wrench was out and that I had over tightened the head bolts in the first place, and the last 1/4 was little to much!  Should the last 1/4 turn be a huge pull with a breaker bar!  :shock:

To check this can i loosen the head bolts as per Bentley with cam belt in place? Or should I remove the cam belt first then loosen as per Bentley and tighten again with another Torque wrench?

As for mis-diagnosis.  I am not what you mean about the coolant flanges.  The vangaon engine is laid over at 45degrees and if I look under the injector pump and around the back of the engine (no.4 cylinder?) I can see the blue coolant seeping out.   Where else do mean that it could leak from?

Sorry for my ignorance but I really want to be able to fix it ....

Again thanks for your help.

[SMOKEYDUB]

the last 1\4 turn is always very hard so i would do it if you didnt. im not convinced it will fix your leak though. sorry im not to familiar with the vanagon setup.

[Quantum TD]

Some claim the newer gaskets don't need the last 1/4 after 1000k, so If you're close, I think it will fly just on startup. Obviously, you'd want to do the whole procedure correctly, but if just for startup and no turbo, that would be close enough (I would think).

After only 5 min of running, and it's leaking suggests (sadly) that your block may be cracked (as noted by Riverfurm). Unfotunately, the only way to find out is to pull the head again, and look for cracks. You'll have to pull it anyways to replace the gasket again (if that is the problem). Usually when a gasket leaks water, there's just a faint trace of coolant that gets cooked onto the block. A 'trickle" sounds a bit more ominous.

Here's hoping I'm wrong.

[joe1975]

I did look for cracks when it was apart, both in the head and the block.

Dam it, it could be one of many things, i just need to work out a plan of attack from here.

[Quantum TD]

Some cracks can be so faint when cold, that only a magnaflux will show them.

Again, here's hoping I'm wrong.

On a side note, how was your head 'skimmed'. I once had some guy refinish my head, and he used a belt sander! He ended up taking one corner down about 10 thousands more than any other corner. I never installed the head, but I would imagine it might leak as bad as what you're experiencing.

Good luck :!:

[joe1975]

it was skimmed by a reputable guy who does loads of stuff for the local garge.

what is magnaflux??

[boosted_diesel_84]

it was skimmed by a reputable guy who does loads of stuff for the local garge.

what is magnaflux??

magnaflux is a way for checking for cracks in iron and steel, will not work in aluminum, its a big electro-magnet that is set on the block in a certain location, and when u  power it up, there is a special magnetic powder you spray onto that area, and if there is a crack, the magnetic powder will fill in the crack and make it visible to you. if no crack then u move onto another area and repeat. works very well.

[joe1975]

sounds great but I dont have one

really not sure what to do next?

[Vincent Waldon]

When you pulled the first head gasket was it obvious where it was leaking ?

Two headgaskets in a row that leak coolant in the same spot sounds suspiciously like the headgasket might not be the actual problem... cracked water gallery in the block a likely alternative, as previous posters have said.

The scientific approach might be to pull the engine, disassemble, and get the block magnafluxed at a reputable machine shop.  I'd worry that putting a 3rd headgasket on at this point might be a waste... unless it's really obvious where it is blowing.

[arb]

Magna-flux is great for cast iron but not the head as stated. There is a 2 or 3 part (depending on the vendor) process that will show cracks on either. It uses spray cans with (3 part) a cleaner, an agent, and a developer. It works...

BUT, unless I missed it, it sounds like you did not pull the final 1/4 turn on the wrench during assembly. Did you also warm the engine up after this to operating temp with the expansion tank cap off, then allow it to cool completely, and then do another 1/4 turn ? If not, it is likely your technique and not a crack. That's my 2 cents.

[joe1975]

Good news.  
After cleaning up the entire area, I decided to be at the engine on start up to work out exactly where the coolant was coming from.  
I manged to work out that i had a leak in the pipe that goes from the water pump to cylinder head.  This was only a drip but leaked onto the small flange of the head gasket that sticks out.  Being that the vanagon engine is laid over at 45 degrees it meant that the water then ran around the head gasket lip until it reached the back of the engine. This then dripped onto the turbo, making it look like a head gasket leak.

Pipe that was leaking.
Added to this the pipe that came out the back of the cylinder head was also leaking.  When I had the head off i never touched this but after looking at it it has been leaking for a while as when I took it off the head was corroded.


Corroded head
Even with a new gasket it still leaks so i need some sort of sealant. Any ideas?

So it seems that my head gasket is fine just some leaking water pipes.  It makes me think this could have been the problem all along ...

The one strange thing i did notice is that the brand new turbo seems to be leaking oil into the exhaust!
I first noticed oil coming out of the exhaust


And when i looked at the turbo i noticed that it was dripping out of the gasket between the exhaust and turbo.

Any idea why this is?

[joe1975]

could anyone confirm for me what the head tightening sequence is?  I mean the last 1/4 of a turn is done after the first start up or after 500miles?

tomorrow  i will take off the exhaust to try and work out why the turbo is leaking oil into it. plus I will try and use some sort of gasket/sealant to stop the water leak which i wrote about in my last mail.  finally i would like to put the vanagon back on the rd for the first time in months :shock:

thanks for all your help

joe