Got to be Gasket??

[sammi49]

Hi All,

I've got a 2000 Wreg Tdi (the 115bhp one). I've had the car a year now and its using more and more water. Initially only on long journeys it would empty the header tank by over pressurising and blowing all the coolant out past the cap (I've changed this) and out the drain hole. Now its about every 60 miles! No water in the oil or oil in water but some sooty deposits inside the header tank.

I've had a really good check for leaks anywhere else in the system and nothing. Its got to be the head gasket, right? Has anyone else had experience with this. The car hasn't got hot/over heated at all. Do I need to skim the head if I change the gasket?

Oh, one more thing...Haynes says an error code will result from the work. Anyone know which code tool I need to get (OBD2 or what)?

Thanks
Sammi

[vwcabriolet1971]

Get your MOT garage to do a "sniff" test to check for combustion gasses in the expansion tank. This should tell you whether it's a cylinder head gasket leak or not .

[sammi49]

Thanks for that. I'll have try my local garages to see if they can do it.

Any one else know which diagnostic protocol I'll need?

Cheers
Sammi

[vwcabriolet1971]

Thanks for that. I'll have try my local garages to see if they can do it.

Any one else know which diagnostic protocol I'll need?

Cheers
Sammi

It has to be an MOT station as they will have the equipment to do this test . They will use the exhaust emission sensor that they normally put up the exhaust pipe to measure emissions . In this case they would put the sensor just above the expansion tank cap and then open the cap ( without the engine being too hot). The sensor will then be lowered just above the coolant level to pick-up any combustion gasses. The other test to determine if the cylinder head gasket is gone is a compression test which will be a little more labour intensive on a diesel , i.e. would cost quite a bit more .

[jondonkin]

Hey, I have this same problem to sort out on my Passat too (1.9 TDI Sport 2001, AVF Engine code)

I didnt get a sniff test done but I did manage to fit a tube and bottle to end up at the same conclusion really.

If you want to do this as it wont cost you anything but time;

Find a bit of tube and an empty clear bottle (I think I used a lemonade bottle)

Then you need to fit the tube to the vent on the botton of the header tank (3 screws got the header off for me so I could see). I found the old pipe off my bottle rocket launcher was just a shade to fat but a stanley knife fixed that (on the pipe of course)

Then you pop the other end into the bottle and find somewhere for the bottle where it is upright-ish and you can close the bonnet.

Drive around for a while and then take a look at the bottle, if you find it half full of coolent then it is and a little stream of bubbles coming out of the pipe then I can think of nothing but the head gasket leaking gas into the water system.

As a bonus though you get to pour the coolent back into the header tank which is much better than it dropping on the road or having to top up with water all the time (no coolent is bad I am assuming, lack of corrosion inhibitors ect)

Speaking of this, does anyone know of a how-to guide on fitting a head gasket, preferably to the model I have? I will be attempting it anyway in a week or two but a guide would be great.

For your viewing pleasure, a pic of my bubble bottle (thats on tickover after a 25 mile drive, about 1.5l of coolent dumped!)

[DSG4ME]

I think I might know what this is, on some VX cars there is an intercooler that runs oil and water through it in different channels, but when it breaks it allows the oil into the water, whether VAG use a similar system or not I don't know, but it does sound very familiar.


Don't waste time with sniff testing, it's not conclusive, the water will contain hydro carbons anyway, and the test will read this, best test is a block test.

[sammi49]

Wow, I wish I'd thought of your bottle trick earlier! Would have saved myself litres of the expensive red stuff!!!! Good work. I did speak to my local M.O.T man and he said he used to have a special tester for the gas in the system but that was 10 years ago.

I've now had the local VW dealer do a pressure test and its definitely over pressurising and only leaks from the header tank so its head gasket time. They quoted £700+Vat by the way! I need to do the cam belt too so its time to roll my sleves up. Thanks for the suggestions.

Sammi

[jondonkin]

Just to let you know how I got on with mine, it was indeed the head gasket. Fixed it myself.

Seems gas had blown through the middle of the gasket about 3mm (It was thick, 5 steel layers and with black stuff between). Then up through to the top layer and around the pot a little and then out to a waterway. There was a little damage to the head where the gas had eaten it a bit (best to fix these things than just make do with a catch bottle for any length of time I can see)

I eventually decided after checking about skimming and looking at the price of a new head I decided to just use a little alraldite metal to fill the ding in the head as it was only a small groove and it did not start at the edge of the pot (I will post a pic if I remember later), bolted it back up swiftly, certainly is a lot cheaper than getting a new head (and being my own car I dont mind giving it a try - so far it's all good).

Skimming: I did want to get the head skimmed, logically this is the best way to fix damage and save the cleaning time BUT I was told that you cannot skim aluminium diesel engine heads unlike petrol engines. It is either OK or you get a recon/new head along with all the extra work that involves swapping bits over.

Well I guess you *can* skimm the head but if you do it can increase the compression ratio too much (diesels are really high to start with anyway) and this can lead to critical failure with parts cracking or breaking due to far too much compression. It all made sense to me and I read the note on VW Elsawin saying the heads are not reworkable so I guess it is true unless anyone else has any experiance on this (I am but a lowly DIY dude) - I did hear rumor of 3 different thickness gaskets though, I wonder if the thicker gasket option would work along with a specific thickness skimmed from a head ... ?

DIY info: (As it was all new to me ) It took me the weekend to do in all, apart Saturday and back together Sunday. I got very oily.

The most time wasted was scratching my head while working out how to get the exhaust manifold/turbo parts off the head without undoing the oil pipes on the turbo, eventually sussed out that if you just lift the head up 2cm and then to your right and it slips off without issues, reverse to put back on. (WD40 on the manifold bolts is a good thing)

Be careful cleaning the head, it is aluminium (I think?) and that means it is soft. I used a green scouring pad, this worked great.

Ensure you have a large socket bar for doing up the head bolts and also the correct socket/star drive thing for the head bolts is essential, that last 1/4 turn is rather tough (Head stage order for me was hand tight all bolts (in the right order this is), then 40nm, then 60nm, then 1/4 turn then another 1/4 turn.) I had a massive bar and it was not easy.

Dont stick all the bits in one pile, try to keep them seperate, one way is to get a sheet of newspaper and write a note next to each pile of bits with a chunky marker - it helps avoid "spare bits" when putting it back together (I did not have any spare bits )

Jet/steam wash the engine before doing the job - you will not get as oily as I did


Yes - I would do this again (lets hope not but still), saved myself a sizable chunk of cash and got some good XP, heres hoping the clutch does not go next month

Edit: Uploaded a pic of the head damage, I think I will get away with the smear of plastic metal as the head has a good 3mm between the edge of the gasket/pot and the damage due to the way it blew, luckey I guess. The groove was not very deep (0.2mm to 0.4mm). 1600 miles so far

[vwcabriolet1971]

I doubt if the araldite will last very long.

[sammi49]

Hi All,

Have been so busy stripping the car bit by bit I'd forgotten to check to see if anyone had replied! Almost ready to take the head off but don't have a hex big enough to get the damn fuel filter off!!!!
Anyway thanks Jon for all your info, especially the photo. I know what to look for now.
I'll let you know what I find.

Cheers S