Can faulty headgasket blow water pipes?

[Sagemagoo]

Linked into my earlier post this morning, just topped it all up with coolant and took it for a test run - ran fine until the 3 way coolant hose from the pump - rad - oilcooler blew and emptied my nice new coolant all over the A41...

Bugga.

Some Q's:

1. I have a slight coolant leak from the head gasket - is it worth trying to torque this down (replaced 6 months ago) or just go for a new one?
2. Could the leak pressurise the coolant system so much that it blows a hole in the pipe?
3. Anyone know where I can get hold of a replacement pipe part 068 121073G? App it's obsolete.

So much for the holiday tomorrow...

Ta

[Sagemagoo]

Bump - yes they can according to the nice AA man who pressure tested it on the hard shoulder of the M4...

Being relayed home again...

Anyone recommend a good vw mechanic near Watford?

[kevtherev]

I think you mean the water jacket seal that's leaking. It's not a head gasket.
There is a "head gasket" on top of the cylinder liner. but the "o" ring below it is the coolant seal.

The water jacket gasket surface becomes pitted, this is why it leaks.
There is a method of dressing the mating faces with JB weld to fill the pit holes prior to fitting the rubber seal

has the coolant been gas tested to see if there are any combustion gasses present in the coolant?
pressure would only come from the cylinders. if the steel "o" ring fails or the head is holed.
otherwise you have a blockage in the coolant system.
I would think.

[Sagemagoo]

Thanks, AA man tested and said no combustion gases present but coolant was pressurised too much, I got some coolant leakage around the head gasket seal. How do I check for a blockage- hosepipe job?
Cheers
Gordon

[kevtherev]

have you bled the cooling system of air properly?
read this an follow the instructions...

http://www.brick-yard.co.uk/forum/bleed ... 29710.html" onclick="window.open(this.href);return false;

[Sagemagoo]

Yep - printed it off and followed it religously tho too much pressure to open cap once it's warmed up. Burst my second pipe last night, the joint between the long pipes leading to rad. Heater warms up and rad bled by bleed bolt. When I refilled after 1st pipe blew it only took 6 litres coolant, either didn't drain all the way or poss block as you mentioned?

[kevtherev]

So the radiator is getting warm too?

from top to bottom?

[fodtommo]

To pressurise like that you have to be forcing air into the cooling system from a combustion chamber - get a garage to run a compression test this can help confirm.

It sounds like the pressure is due to a head gasket fail, or given the pressure build up possibly a cracked head (I have had this on more then one diesel engine in the past)... really either way its head off pressure / crack test to be sure, weld repair if it is cracked, and ideally skim prior to rebuilding. I dont have any good news im afraid

Im not scaremongering but being realistic. If you dont mind whipping heads, off a quick gasket change to see if it works is worth a shot - rare though I can only think of a couple out of the 10s ive done that didnt need at least the head skimming.

[Sagemagoo]

Gents, I'm obliged.
It's off with her head then - I'll let you know how I get on...
Thanks
Gordon

[Sagemagoo]

Lots of posts with lots of advice but often no mention of how the problem was finally resolved, so a bit of closure for my overheating problem..

1.9TD AAZ, kept blowing pipes, pressurising the header tank and overheating - diagnosis head gasket gone.

Replaced the head with a secondhand one (Thanks Ringo), skimmed and new gaskets - still overheated but coolant level remained good.

Dalek cap tested and faulty, replaced.

Replaced the thermostat even though the old one was only 2 years old - big improvement in temperauture.

Pressure jetted through the radiator, loads of gunk and sludge out, Brickwerks bleeding guide followed and hey presto, needle now stays in the middle.

It was obvious I had a couple of things going on at the same time - made it a lot harder to get to the bottom of it but got there in the end.

I do still have a coolant drip from the head gasket but only when stone cold - K seal here I come...

[kevtherev]

Radiator sludge is an unseen culprit... good point made
When a coolant change is due the radiator should be cleaned out, 25 years it has accumulated, and reduced the efficiency of the radiator.