Blown head gasket X2

Hello,

In the summer i noticed the temp gauge rising when driving the car hard, up long hills or with a trailer. I lost hot air from the heater when driving up hills. Level of coolant also went down thru the overpressure hose from the tank.
In september the head gasket was changed, head was pressure tested etc. The car ran just without any problems for 1 month until today when the same symptons showed again. Rising temperatue when driving long hills, and loss of hot air from heater.

Any suggestions why the head gasket blows after just 1 month?

The car is a 2001 passat 130pd tdi, and has 380000km on it.

Did you do the work yourself or did someone else? My guess is your head is warped which caused your gasket failure in the first place and if this was over looked during the repair, it is no wander your second gasket failed in short order. The only other thing that comes to my mind is your head bolts were improperly torqued. I had a head gasket failure on my 05' which was caused by improperly torqued head bolts. I changed the gasket, checked the head for flatness, and I made sure to use a high quality torque wrench when tightening the new head bolts. I have since put over 30,000 miles on the car and it hasnt skipped a beat!

This next time around, make sure to send your head off to a COMPETENT machine shop who is familiar with tdi heads. Use all new fasteners and make sure you use a known good torque wrench. Sorry to hear about your misfortune but it may prove to be a good lesson learned.

Take care.

Yup... to be more specific: did you have the head re-surfaced for flatness during the first head gasket replacement?

The head was done by a machine shop by a person who are familiar with diesel. The head was milled, and pressure tested. The head bolts where new, and torqued in the same sequense, and torque as described by the guy who did the head.

Hmmm... all the right steps.

I guess that leaves much more rare possibilities. Things like a new breach in the head itself, a defective headgasket, or something about the deck from the first time. What kind of deck prep was done?

the block was prep manually with sandpaper. then cleaned. the threads for the head bolts was also cleaned/vacuumed. I guess there is many possibilities as you describes... My guess is the block itself . I will ask the mechanic who done the head tommorow.

Was the block checked with a straight edge?

I would pressure test the engine before disassembly to determine the source of the leak.

How do you know it is a blown head gasket? Other than the loss of coolant under load symptom, have you had any tests performed? A common issue for the passat head is to develop a crack somewhere, not too brushed up on the specifics but point being it could be a crack that only opens up when the head is hot. If it is located near the valve seat or in the intake runner it could also over pressurize while under load. This may have been your issue all along or this might be a new issue all together...unlucky either way.

Edit: Maybe I shouldn't say "common" when talking about cracks in the pd head but I know I have read about it happening on more than one occasion and it has been mentioned as being "common".

newlitemotorist said:

...Edit: Maybe I shouldn't say "common" when talking about cracks in the pd head but I know I have read about it happening on more than one occasion and it has been mentioned as being "common".

Click to expand...

8V PD heads crack pretty often when tuned. Most of those cracks are no big deal though and I have never heard of one cracking into the water jacket. But, the nature of a crack is that they like to propagate.

I'm with Windex, pressure test the system first thing, preferably when hot.

I think the problem wasn't the headgasket in the first place. Did they show you where the old gasket faed?