Thread: Over pressure in coolant header tank

First up,, what year is the Disco?

years not so important diesel vs v8 is and if pulling the injectors lets him check the pots im tipping its a diesel and I reckon the head gaskets gone.

Just because you can't see emulsified water or oil doesn't mean there isn't a failed head gasket. A very small failure between the cylinder bore and a water jacket portion of the gasket could pressurize the tank and hardly show up in the coolant as the milky sludge that people usually look for.
Can you get a chemical test on the car to see if CO2 or hydrocarbons are entering the header tank?

Sounds like a head gasket at the end of the day...or at worst a cracked liner/block?

Thanks for the replies - I really was procrastinating.

I lifted the head - and of course found a leak from 2 and 3 across to the cooling water.

Head was still flat, valves only needed a slight touch up, so I am lucky.

Interesting that since putting it back together, the oil is a lot cleaner ( Tdi with 300,000k on the clock) than it was. Maybe I have been getting some blow by for a while?

Anyhow, now I have a new tank that I can see through to check the water level, and I have a level switch in the pipeline.

Here's to some happy times.

thanks