High Pressure in Coolant Tank

[zollaf]

i have tested many diesels with this kit, and only once had it change colour a tiny bit. mind you, i am not convinced it changed colour because of gas in the cooling system or a contaminated filter on the tester.

[adamss24]

The sniffer tests only work on petrol engines and even then you need to take them with a pinch of salt ! I had a 2.0 petrol passat with a cracked head a few weeks ago, owner had a backstreet garage do a timing belt job + water pump and did not bleed the system. Subsequently the owner put cold water in the hot engine as it was pressurizing the coolant tank and water went trough the relief valve. It never overheated and temp. stood bang on 90 C on the gauge. Took the head off, sent it for skimming and pressure test and then refitted with a new head gasket and head bolts. It did the same after 3-4 days, water dropping from the header tank, told the chap his block is cracked so he needs a 2nd hand engine, he did not take it nicely !

[ShaneA4]

As most of you will know I have just upgraded the turbo on my 1.9tdi. All is well and just doing a few MOT repairs. But I am not happy about the coolant. The main pipe that goes from the head to the radiator is really hot and hard after a run. And when I undo the tank cap it releases a hiss of pressure and the little pipe that goes into the tank shoots water through it into the tank. Just a bit confused as to why and i am not happy with it.

The only things i can think of are; the tank cap is blocked (already cleaned and blasted with an air gun), a blockage elsewhere in the system (going to drain and flush out thoroughly), the turbo is creating a high pressure inside the head....? (actuator not set up properly yet and running a massive boost!)

Any other thoughts?

Rich

Did you ever get this sorted having the same problem cheers

[Victordugg]

Did you ever get this sorted having the same problem cheers

I also have the same problem has anyone resolved the issue?

[FrenchAudi]

I also have the same problem has anyone resolved the issue?

It is normal for the pipe to get quite hot and for the tank to be under pressure once the engine is at working temperature. The cap should not be removed when it is hot.

Is your temperature gauge reading higher than normal, i.e. more than 90º?

Are you removing the cap before the engine has cooled down?

[Victordugg]

My question was with regards to the original post 'high pressure in coolant tank' i'm having the same problems, pressure got so high it popped the radiator (which was the first thing the mechanic changed about a year ago). Ive also changed the water pump and thermostat still no joy. Thinking of buying a second hand engine but i think i'm going to have one last go with changing the oil cooler. But I the oil isn't mixing with the coolant, can it still be the oil cooler? Also does anyone know how I can tell if it's got an egr cooler, where would it be located? I've read in another thread, someone with similar problems changed this and problem as fixed.

[alowsa91]

Hi guys, after chasing a similar problem on my b5 with a 115bhp ajm engine code it turned out to be the headgasket. I was having similar issue; rock hard top hose, pressurised bottle etc. I sniff tested it and it passed sniff test, changed expansion bottle and cap with genuine parts and a genuine stat. Nothing resolved it till I pulled the head. Hope this helps.