coolant system pressuring up

[goldenwheels]

as in title got air getting into my coolant system causing it to over heat i have had the head pressure tested and was fine new gasket new bolts new rad new water pump new thermostat checked everything i know . could anything to do with the turbo cause this ? someone mentioned the other day about turbo seals ??? im not clued up on turbos can anyone help ????

[RoboPope]

Turbo seals normally pass oil on overrun when they are starting to wear you will find it lurking in your inlet pipework, this can also be caused by using too thin an oil. You would see smoke from the exhaust if things are too bad

Personally i would check the water pipework to the turbo and make sure it isnt touching the exhaust manifold where it isnt supposed to be. There is also a bleed bolt for the water system roughly in the middle inlet manifold side if you arent aware of it (air expands loads when heated and will displace the water if not fully removed)

Heres a question for you though, is it backing up the water out the filler cap of the expansion tank? this can be caused by a faulty rad cap of all things. bear in mind if the air is getting in the water has to go somewhere...

Where in the world are you, if you arent too far away then you could pop over and we can swap some parts out to find the problem

Pope

[Buster]

From what you said on here and the other site, it sounds like you have a blockage.
Just because you have fitted new stuff, dont depend on it being OK. Sods law will prove you wrong at some stage.
Is the thermostat opening or fitted the right way round ? Test it in a saucepan of boiling water.
You say you flushed it but did you get a flow through the engine block and heater system with the thermostat removed but the cover fitted ?
Did you bleed it and start it with the heater on hot ?

If you think about the system and how it works its the most basic bit of crap you can imagine.

Its a sealed low pressure system

Padlle to move water (its not a pump as such at all)......thermostat to keep water in one place until it reaches a working temperature......thermostat opens at set temp and water flows around the ports and chambers....through the heater if the valve is opened.....into the radiator where it is cooled....back to paddle.
The radiator cap is a safety valve, if it gets too hot and pressure builds, the cap lifts and allows the pressure to vent. The radiator cap also keeps the system under pressure as it helps with the boiling point of water (physics stuff)

[goldenwheels]

robo im in camberleysurrey near japsalon remember talking to you before about some bits

[RoboPope]

Ahh well there we are then, I'm in near wokingham so if you want to pop over we can have a fiddle if you want.

out of interest what happens if you run it with no thermostat?

Pope

[goldenwheels]

robo pm me a contact num and i will get in touch

cheers

[goldenwheels]

thought it was sorted everything was good but played up again today any ideas ?

[Buster]

Was the head skimmed when the gasket was changed ? Did they do a crack test ?
Was it re torqued down after a few hundred miles ? Have you had a compression test done recently ? It all points to a head or head gasket prob

[goldenwheels]

had it tested and skimmed about 2 weeks ago and i have only done about 20 miles since only got it back on the road yesterday and trouble again today i might surrender and take it to a specialst doing my head in now

[Deggers]

Head Gasket fault under boost.

Only noticeable when you have been giving it some welly?

Tootling off boost and it behaves?

I had a similar problem. Went for various HG tests and it passed everytime.

It was the HG in the end though in my case.

And I had gone through the same as you did... new radiator, radiator cap, thermostat, flushed the system.. kept being told it was an airlock, flush flush flush....

[goldenwheels]

update more testing done tonight . we got the engine warm then switched it off removed the top rad pipe from the rad but left it connected to the block and twisted it upwards we then ran a hose pipe into the top pipe and water flowed around the system and back out the top of the rad as expected but as soon as we tried it with the engine running the water just backed up and came back out the top rad pipe we were filling through , as if some thing was blocking the waters flow , turned the engine off and the water flowed round the system and back out the top of the rad any ideas

[alexj]

i may be making an arse of myself but ... shouldn't the water normally flow out of the engine via the top rad pipe to the rad? in which case you'd get what you describe.

with the engine warm but switched off the thermostat is open so you can make water flow round the system as you describe - but the minute the engine is running the pump is pushing the water in the oposite direction than you are trying to make it go.

[goldenwheels]

alex you maybe right i thought the system went the other way does anyone know ????

[Gambit]

I think alex is right with that.

[RoboPope]

the pump is on the return not the flow so it should drop when you rev it and back up and out when the revs drop and the pressure equalises

unfortunately deggers has a point although thats an easy test on the water in the expansion tank

Pope

edit to say not in a bad way, deggers point is very valid