Head gasket or possible egr cooler?

[Seatman]

Got a 2007 2L tdi single cam PD lump. Been having issue with the pressure pushing coolant out the cap. Tonight I was able to get a pressure tester hooked up and went for a spin. As soon as I hit a big hill and gave it plenty of right foot the pressure rose, eventually went over 20psi!

Now my thinking is the head might be lifting a touch under boost but someone suggested it could be the egr cooler which I'm reluctant to think possible. Only coolant I seem to lose is from the cap itself.

My experience of a cracked head caused constant pressure and that was without a turbo in a petrol car with less compression so I'm kinda ruling that out.

Anyone have any other input?

Cheers

 

[Drewser]

So kind of "apples to oranges" comparison here, but I just dealt with a blown EGR cooler on an 04 Passat. Bought the car for $300 because mechanic said it had a blown head gasket and needed a new engine. Pulled tube from EGR cooler to EGR off and when it started it blew coolant out all over everything. Replaced, ran for quite a while to clear the coolant out of exhaust, and now seem to be running great. In my case, I did a compression test and all 4 cylinders were reading good numbers and close to each other.

 

[jmodge]

Can you bypass the egr cooler by pulling the hoses and linking them together, then do your test again

 

[Seatman]

So kind of "apples to oranges" comparison here, but I just dealt with a blown EGR cooler on an 04 Passat. Bought the car for $300 because mechanic said it had a blown head gasket and needed a new engine. Pulled tube from EGR cooler to EGR off and when it started it blew coolant out all over everything. Replaced, ran for quite a while to clear the coolant out of exhaust, and now seem to be running great. In my case, I did a compression test and all 4 cylinders were reading good numbers and close to each other.

I'm getting zero coolant loss other than out the cap, doesn't seem to be going into the egr pipes at all.

Can you bypass the egr cooler by pulling the hoses and linking them together, then do your test again

My main thing about is it even possible for and egr cooler to put that kind of pressure into the cooling system? Does the exhaust creat that kind of pressure? I was hoping someone might have a good explanation of the exhaust system and what is and isn't possible. Save me pulling a load of bits out to get to the stupid pipes lol

 

[jmodge]

When the vanes of the turbo close to build boost, it builds pressure and heat in the exhaust manifold pre-turbo. Look up and read about exhaust manifold pressure. I think you’ll find that it increases almost to the point of boost pressure. Then take a note of where your EGR cooler is mounted, on the exhaust manifold, pre-turbo.

 

[Mozambiquer]

I'm getting zero coolant loss other than out the cap, doesn't seem to be going into the egr pipes at all.



My main thing about is it even possible for and egr cooler to put that kind of pressure into the cooling system? Does the exhaust creat that kind of pressure? I was hoping someone might have a good explanation of the exhaust system and what is and isn't possible. Save me pulling a load of bits out to get to the stupid pipes lol

Yes, is the short answer. I had the exact thing on my 2005 Passat with the BHW engine. It was blowing out the cap as well.

 

[Seatman]

Yes, is the short answer. I had the exact thing on my 2005 Passat with the BHW engine. It was blowing out the cap as well.

Perfect, cheers bud, that's the sort of thing I like to see, someone else who has actually had the problem and fixed it. Google just brings up coolant out the exhaust, mysterious coolant loss etc. I only get a bit out the cap and that's it.

Head gasket was done about 5 years ago, 65,000 miles. Mate used to own the car and had it done when he owned it but he had constant overheating and all sorts like you'd expect from a bad gasket. I've only had overheating twice and both times it was a little restrictor in the return pipe choked up.

Anyway off to dismantle my car and bypass the cooler. Due to the way my car is set up it's a bigger job to do which is why I didn't just dive straight in and try it.

 

[Mozambiquer]

Perfect, cheers bud, that's the sort of thing I like to see, someone else who has actually had the problem and fixed it. Google just brings up coolant out the exhaust, mysterious coolant loss etc. I only get a bit out the cap and that's it.

Head gasket was done about 5 years ago, 65,000 miles. Mate used to own the car and had it done when he owned it but he had constant overheating and all sorts like you'd expect from a bad gasket. I've only had overheating twice and both times it was a little restrictor in the return pipe choked up.

Anyway off to dismantle my car and bypass the cooler. Due to the way my car is set up it's a bigger job to do which is why I didn't just dive straight in and try it.

I would not rule out a head gasket, but an egr cooler is a lot easier and cheaper (most of the time) and can cause the same exact symptoms. Then bypassing it will rule out the cooler, since if the pressure is no longer there with it disconnected, then you know that's what the problem is.

 

[B3achbum]

I've had an EGR cooler failure once. In my case, the telltale was in the rear view mirror (clouds of white smoke). I suppose it could get perforated and leak exhaust into the coolant when system is cold somehow... Depends on the design/arrangement of the cooler I would imagine. Aren't BEW and BHW systems similar?

Especially since the gasket has been replaced, I'd be suspicious it has failed again. If you have a do-over on your hands, might as well upgrade the headbolts to pd150.
But bypassing the cooler/coolant lines will be a definitive test of cooler leak. You can also get a kit to test for exhaust gasses at reservoir afterwards to be sure it is head gasket.

Good luck!

 

[Seatman]

I would not rule out a head gasket, but an egr cooler is a lot easier and cheaper (most of the time) and can cause the same exact symptoms. Then bypassing it will rule out the cooler, since if the pressure is no longer there with it disconnected, then you know that's what the problem is.

I've had an EGR cooler failure once. In my case, the telltale was in the rear view mirror (clouds of white smoke). I suppose it could get perforated and leak exhaust into the coolant when system is cold somehow... Depends on the design/arrangement of the cooler I would imagine. Aren't BEW and BHW systems similar?

Especially since the gasket has been replaced, I'd be suspicious it has failed again. If you have a do-over on your hands, might as well upgrade the headbolts to pd150.
But bypassing the cooler/coolant lines will be a definitive test of cooler leak. You can also get a kit to test for exhaust gasses at reservoir afterwards to be sure it is head gasket.

Good luck!

My engine is a 2L PD140 lump, BRT engine code, I'm in the UK where we got a lot of options.

I've just been out and bypassed the cooler, I've had very minimal coolant loss but today I did find what looks like soot particles in the coolant.

If it is the head gasket I'm ok with it, do the job myself anyway which saves a lot of money and I'll know it's been done to my fussy standards lol. Not sure if the PD150 bolts would be an upgrade on mine or if they'd even fit.

I think it's possible that the head bolts could have been reused, no way for me to know really. The garage were meant to do a complete timing belt including pump while they were at it but when I did the belt last year the pump had definitely not been replaced, had hylomar around it and all sorts and looked really old like it was the original.

My car is what's called a seat alhambra, same as the VW sharan but Spanish, you have to remove the wipers, cowling, bulkhead extension, fuel filter etc etc to get access to the pipes which is why I was looking for opinions first.

Anyway I'll see how it goes tomorrow when I'm out, 40 mile round trip and plenty of hills as well as overtaking to be done which should test it properly lol

Cheers

 

[jmodge]

Now it makes sense why you hesitated at bypassing the cooler, it could also put soot in the coolant. We had so many problems on Internationals with those coolers I developed an allergy and chuck them now

 

[Seatman]

Ok so it is defo the gasket, still to much pressure in the system today. Parts ordered and will fit this weekend. Hopefully that will finally be an end to the saga lol

 

[nokivasara]

Ok so it is defo the gasket, still to much pressure in the system today. Parts ordered and will fit this weekend. Hopefully that will finally be an end to the saga lol

I had same symptoms on my Octy, turned out the headbolts had come loose. Replaced the bolts and it cured it, 6 months now without needing to add coolant! Don't know if the gasket had been done at some point.

 

[Seatman]

I had same symptoms on my Octy, turned out the headbolts had come loose. Replaced the bolts and it cured it, 6 months now without needing to add coolant! Don't know if the gasket had been done at some point.

I have read of people getting away with that, guess I'll find out if that's the case soon enough lol

 

[03TDICommuter]

Keep us posted. I plan on doing mine next weekend.

 

[nokivasara]

I have read of people getting away with that, guess I'll find out if that's the case soon enough lol

I used an old school analogue torque wrench (with a pointer) and was able to turn half of the head bolts close to 1/4 turn before even getting to the 90NM (or is it 60Nm?) you torque them to before doing the additional 90 deg turns.
I did not tighten them further, I ordered new bolts and replaced them one by one.

 

[Seatman]

I used an old school analogue torque wrench (with a pointer) and was able to turn half of the head bolts close to 1/4 turn before even getting to the 90NM (or is it 60Nm?) you torque them to before doing the additional 90 deg turns.
I did not tighten them further, I ordered new bolts and replaced them one by one.

Yeh mine are 40nm then 60nm then 90 and 90 again, I picked up the gasket and bolts today and hoping the weather is good tomorrow to get stuck in.

Was yours a PD? That's the only thing, I have to unbolt the egr cooler to get the intake off to get the valve cover off, by then you're that far into it and it's only another few bolts to get the head off. I'm hoping some are a bit loose though, that would explain everything but I'll just do the gasket anyway.

 

[Seatman]

Keep us posted. I plan on doing mine next weekend.

Will do, I'll probably take it easy for the first 100 miles or so then give it a bit of beans and see how the cooling system behaves.

 

[nokivasara]

Yeh mine are 40nm then 60nm then 90 and 90 again, I picked up the gasket and bolts today and hoping the weather is good tomorrow to get stuck in.

Was yours a PD? That's the only thing, I have to unbolt the egr cooler to get the intake off to get the valve cover off, by then you're that far into it and it's only another few bolts to get the head off. I'm hoping some are a bit loose though, that would explain everything but I'll just do the gasket anyway.

Yes it was a 1.9 8V PD. BLS. Mk2 Octy.
If you have to remove stuff to even get to the bolts I agree that it's better to do the gasket aswell. Are you going to put the EGR cooler back in? I'd probably delete it.

 

[Seatman]

Yes it was a 1.9 8V PD. BLS. Mk2 Octy.
If you have to remove stuff to even get to the bolts I agree that it's better to do the gasket aswell. Are you going to put the EGR cooler back in? I'd probably delete it.

Put it back but just blank the egr at some point. Not sure what the story is at MOT time regarding the light being on.

Also think I've found a spot on the gasket where it's been blowing straight into the water jacket. Number 2 cylinder bottom of gasket. I'll try and get a pic up later if I can remember how lol

 

[nokivasara]

I actually meant to say to bypass the cooler. Keep the egr.

 

[Seatman]

I actually meant to say to bypass the cooler. Keep the egr.

Only problem is the length of the pipe I'd need and where I could get it.

But I think the cooler is fine anyway, made no odds bypassing it the other day. Although bit of a faff getting it off and on the car lol

 

[Seatman]

So here's the gasket and where I think it looks suspicious

20210626_181839.jpg

• Seatman
• Jun 26, 2021

 

[Mozambiquer]

So here's the gasket and where I think it looks suspicious

20210626_181839.jpg

• Seatman
• Jun 26, 2021

Looks like a pass through spot to me.

 

[Seatman]

Looks like a pass through spot to me.

Yeh straight into the water jacket too! Hopefully by the time I've finished the engine will keep going till the rest of the car is dead lol

 

[03TDICommuter]

Yeh straight into the water jacket too! Hopefully by the time I've finished the engine will keep going till the rest of the car is dead lol

How does the head and block sealing surface look? Do you think it will clean up well without decking either part?

 

[Seatman]

Nothing obvious, spent ages cleaning it up with very fine paper and brake cleaner. Couldn't find any damage on the surfaces so hopefully all good.

 

[Seatman]

Ps I'd ideally have had the head skimmed but circu

 

[Seatman]

This set of things are really handy, the egr nuts on the exhaust were pretty much worn out and just a pic of the car all back together to show what I was dealing with.

20210627_173916.jpg

• Seatman
• Jun 27, 2021

20210627_173902.jpg

• Seatman
• Jun 27, 2021

 

[nokivasara]

Only problem is the length of the pipe I'd need and where I could get it.

But I think the cooler is fine anyway, made no odds bypassing it the other day. Although bit of a faff getting it off and on the car lol

It is a bit of a faff, especially if it's a 4x4 like my octavia. At one point I felt like dynamite would be the only way to remove it.
Good call on the head gasket!