Diagnosing possible head gasket?

[serfma]

Hi all - I am a diesel noob. I have an 06 Jetta that I have no idea what the stock boost is but I'm reaching 20-25psi at WOT. I do not know if the waste gate is ECU controlled, or where it's at if it can be replaced. I'm unsure what the previous owner did exactly but it's hood stacked, of course. Having a problem with passing people in 5th gear where ECT will reach 240* rather quickly, then cool right back down when you drop it into 4th. I am reading temps via OBD2.

Pressure tested cooling system to 16psi and had a very minor leak (1psi over 5-10 minutes) but without the tester on it is pushing air straight out with engine running. I used one of the adapters on the reservoir which leaves a nipple so I could see steam pushing out. I used a balloon on the nipple and it filled up almost instantly lol confirmed head gasket off of that alone?

 

[oilhammer]

Sounds plausible.

I'd take the glow plugs out, make sure the cooling system is full, and put a pressure tester on it, see if it pushes coolant into any of the cylinders.

 

[serfma]

Sounds plausible.

I'd take the glow plugs out, make sure the cooling system is full, and put a pressure tester on it, see if it pushes coolant into any of the cylinders.

How much pressure does the cooling system usually take before it passes through the cap? 16? I have a feeling that maybe 16 isn't enough to cause the leak to go into the cylinder. It can idle all day and not overheat but it does lose coolant, unless it's just a small enough leak to not cause anything but a loss of coolant.

 

[oilhammer]

Spec is 1.4 bar... and that's why pressure testers go higher than that. But they won't go as high as peak cylinder pressure.

Don't overthink this. If you've got that rapid of pressure buildup in the cooling system, something isn't right.

It could also be an EGR cooler.... but again, a pressure test would isolate that. If no coolant ends up in the cylinders overnight, but the catalyst and exhaust has coolant in it (blowing out tail pipe when you start it), then the EGR cooler is bad.

Neither is a common failure on the BRM. But if some mouth-breather put a stack through the hood, then who knows....

 

[serfma]

Spec is 1.4 bar... and that's why pressure testers go higher than that. But they won't go as high as peak cylinder pressure.

It could also be an EGR cooler.... but again, a pressure test would isolate that. If no coolant ends up in the cylinders overnight, but the catalyst and exhaust has coolant in it (blowing out tail pipe when you start it), then the EGR cooler is bad.

When it's started up there's a white plume of smoke, but I wasn't sure if it was 100% coolant or something else. It's technically my nephew's car / for my nephew but he traded a running car for it. Had the accessories bracket broken and whatnot that I swapped for him but I have no idea what's been removed. Claimed "EGR delete" by previous owner but again, people can say anything.

 

[oilhammer]

Yes, people can say anything, but your eyes can tell you the truth if you look.

Some white smoke at start up is normal, it just depends... colder weather obviously makes it worse. A "plume" is not normal, but it can happen... since you said it has a stack through the hood, I'll assume the catalyst is gone, and that soaks up some of that start-up puff.

But that could be a secondary concern for now. If it runs good otherwise, anyway.

Are you ready to pull the head off of this engine?

 

[serfma]

Are you ready to pull the head off of this engine?

For sure. Didn't want to if it wasn't necessary but I wanted to gain more confidence before yanking the head. I've a 96 Mustang 4.6 4v that I've yanked the heads off of in engine so this thing will be a cakewalk.

I assume the head bolts are TTY? Also do you know what thread size off hand? Going to get a thread chaser ahead of time. I'm going to have to grab a set of allen head + torx sockets, do I need a triple square set as well?

Took a quick look at a couple videos just to see what I absolutely need to remove (e.g. cam timing sprocket) but the most annoying thing I already can see is the turbo / exhaust being a pain to reach behind lol

 

[oilhammer]

Head bolts are TTY, yes. The head gasket also has variable thicknesses, need to put same thickness back on.

The timing belt requires several SSTs.

You can lift the head off with the intake and turbo on them.... but it is awkward and heavy.

The turbo oil feed pipe will fight you if you don't just take the time to dig it all out and remove it completely. It wraps around to the oil filter housing.

The turbo drain is also the support bracket, and there is a big banjo bolt holding it to the block. Best to replace that bolt, as it comes with seals. There are also two more seals in the drain tube going into the support, as well as the gasket on the turbo of course.

The charge air hose directly out of the turbo is a known problem spot, and there is an updated version (that is orange instead of black).

There are some washers and seals associated with the injectors, as well as TTY bolts for them and the rockers.

The BRM engine harness is notorious for having problems.

The firewall has a removable section, that allows for more room... just remove the wiper arms and the cowl trim, and it can come out.

 

[serfma]

Ok so - according to this post here; https://forums.tdiclub.com/index.php?threads/brm-high-boost-totally-stock.346229/#post-3730708 - it looks like boost should be sustained around 15psi. We're seeing about 20-25psi sustained. I have a feeling, since we only overheat during WOT, that previous kid turned up the boost and didn't add any fueling to compensate. Two questions:

How is boost controlled on these engines? Wastegate via a spring? Controlled by ECU?

What's the tuning like on these engines? e.g. I have a boosted v8 that utilizes a MAF so I can dial in fueling from the MAF curve easily (as long as my fueling system can keep up) Is it via OBD2? Likely a closed off system that we'd have to pay someone $500 to tune? I have no idea if it's tuned or not currently.

 

[Rx7145]

ECU controls the boost. So a retune is needed to raise the boost level.

 

[serfma]

ECU controls the boost. So a retune is needed to raise the boost level.

Do you know what's used to flash / tune these ECUs? Physical chip or are they OBD2 flashed?

 

[oilhammer]

The VNT actuator is vacuum controlled, via a duty cycled solenoid (the N75) that is controlled directly by the engine controller.

You can flash these through the DLC.

The correct way to check the boost is to monitor the Actual vs. Requested in the Engine data blocks, with an appropriate scan tool.

 

[serfma]

Finally convinced him to pull the head with my help. Check out cylinder 1 there! What I'm thinking is that the head warped, lifted, and blew past the head gasket into the cooling ports there.

My issue comes next: What do we do? It seems that resurfacing the head is not the correct call as the valves aren't recessed. Yes we can pull the valves but we would have to run a three hole head gasket, no? I've seen suggestions of having the valves surfaced by however much is removed off of the head.

 

[turbodieseldyke]

Have you checked both the block and head for warpage?

 

[serfma]

Swapped head gasket out, no more combustion going into the cooling system. This is an EGR deleted vehicle that's hood stacked + tuned by a previous owner. I did not use the timing components to put it into time. Saw a few videos of where crank mark was located and lined it up almost spot on. Pinned the cam sprocket incorrectly somehow as it would crank and then sputter, struggling to start. Realized I was off in timing so I jumped two teeth total (jumped one at a time, adjusted cam clock-wise and rotated by hand without glow plugs to make sure no PTV, then observed engine when starting and idling.) and have it centered for the cam. It takes quite a few cranks before firing up and idling / running pretty solidly. Only issue now is boost won't even reach 5psi and it's down on power.

N75 valve is connected correctly. Adjusting timing counter-CW currently will cause it to not idle correctly. Fully CW it runs decent but it's noticeable that it's not right by ear. I do not have access to VCDS or the timing tools. I'm limited by what my nephew wants to put the money into, which I told him will result in him getting a car that runs at half power lol

 

[Rx7145]

Pointless without the right tools.

 

[serfma]

Pointless without the right tools.

If you pin the cam and eyeball the crank you have a whole tooth of a window to nail it. The only thing next is having to grab VCDS to set torsion, correct?

 

[Rx7145]

Some scanners that read live data will also display torsion. And of course VCDS does. I really don’t like eye balling it but it’s up to you.

 

[serfma]

Some scanners that read live data will also display torsion. And of course VCDS does. I really don’t like eye balling it but it’s up to you.

Huh. That's what I thought as well. If torsion is correct then we know timing is on. I've rotated engine over to verify I wasn't too far advanced for PTV. I thought I could view torsion with Torque Pro but I suppose not lol

 

[Rx7145]

That’s doing it with more risk than I would be comfortable with but yes as long as you get an acceptable torsion number, the timing should be OK. An acceptable torsion number is not zero, it has to be something positive or negative.

 

[serfma]

I have access to diagrams -- but what in the world is the N75 valve called? Anything for "boost" I cannot find. I am thinking that a ground was removed somewhere or something could've been nicked (if not a fuse popped) and I cannot for the life of me find correct diagrams.

 

[oilhammer]

What a train wreck....

 

[serfma]

It's ok. I have it figured out and running fine now. I was correct the first time in terms of timing. Crank is going to move the moment the tool is removed, with cam pinned, so no you do not need the tool in this application unless you're blind.

Didn't know the VW platform, thought it'd be better to ask than to blindly guess, but I was wrong.