coolant problem persists

[Legion84]

Hi guys any idea what the next steps to take will be, I had a coolant leak a couple weeks back I changed the header tank, seem to of been ok, but a couple of days later I thought the new coolant tank was defected cause the same problems came back, after speaking to the vauxhall dealer I bought the header tank from asked if I changed the cap which I hadn't done, so he checked it over could hear pressure escaping, changed the cap ran ok for a couple days again... its back again, had the garage pressure test the system its ok, oil is ok coolant is ok just losing it and it seems to be around the header tank area, I've took the pipes off seem to be ok no blockage, but excess pressure maybe in the header tank, took the cap off ran engine no volcano effect, smelt inside the header tank doesn't smell like engine fumes,

One weird thing is I hear a weird pressure noise on the front radiator for a couple of seconds after engine turns off, then a weird blow off noise near the air filter any ideas guys please, driving me nuts thanks. Ps sent from phone sorry about wall of text.

[Caveman_nige]

I would be looking at the water radiator for possible leaks.. plenty of spares of these and easy to fit..

[Ben50n]

Always try a bit og good old Radweld!

[Bigtee]

Always try a bit og good old Radweld!

No it clogs up the heater fix the problem.

Pressure test is pumped up to 13 psi how long was the pump on for did the gauge drop pressure?

You should have coolant fitted can you see with your torch any coolant anywhere in the engine bay?

Sprinkle talcum powder around hoses/tanks/etc if it leaks you will see it.!!

It may only leak when hot and may just be a pin hole enough to spray out.

[Chris SRi]

Slight split in pipes that attach to header tank?

[Legion84]

Pressure test came back ok, sorry don't know how long or at what pressure, took hoses off and back on to make sure pipes were ok flushed them out the small top one, blew through small second pipe connected to the coolant tank, coolant gushed through the main pipe underneath, don't really want to use radweld if possible, only other concern is a weird pressure noise from front right radiator after engine is turned off, lasts 5 seconds or so then once that stops I hear a pressure blow off near the brake fluid tank area near the air filter... any ideas on that thanks guys, small pin ***** in hose could be one problem, as the tank usually has coolant on the outside..

[Legion84]

Ps also when I remove coolant tank cap even if been stood over night to cool the coolant raises about 2 to 3 inches in level

[Graham]

Sounds like excessive pressure in the system.

Is there not a pressure relief switch some where that blows of when at a certain pressure?

May be this relief valve is faulty.

[sheepish]

Silly suggestion, but you've definitely bled all the air out of the system haven't you? ...disconnect the heater matrix pipe, etc, etc...

re pressure test: get them to leave it on for a couple of hours at least if your still having problems

re leak: if you still suspect a leak, go out in the dark with a torch and warm the engine, any faint sign of steam will show up in the torch beam.

[Big Knox]

I had a mysterious coolant leak for weeks. It only seemed to start when engine was up to temperature. Turned out to be a 3-4in piece of hose near the thermostat had a small split in it.


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