Cerb Coolant /Temperature Problems

[big g]

I am having a few temperature and coolant problems with my 4.5 LW.....
Original problem couple of months ago was a leaking hose and resulting in overheating, this was rectified and all seemed well.
A couple of weeks ago I had similar problems but diagnosed by my dealer as a radiator leak under pressure, which was replaced and silicon hoses fitted.
Now the cerb seems to be running up to 100 before the fans kick in... but more odd is the breather pipe on the left side of the head (pipe that double back on itself) has now 'blown' itself off twice spraying oil around.
The only other odd thing is the tem gauge ...in the morning it sticks on the rest until it suddenly flicks round to 70-80 and then behaves normally.
My guess is that the engine running so hot is causing these problems ....has anyone any ideas please?

[satman]

Could it be a 'sticky' or 'faulty' thermostate valve?...cold water suddenly becoming hot water as the valve decides to open..leading to a sudden jump on the gauge reading...or otherwise a possible air lock in the system....

[shpub]

Sounds like a air lock. Also could be low level, Silicone hoses need tweeking up after a few days to ensure they don't dribble. It is possible that you are nor very low on coolent. It takes a few hours to fill the car because you need to run it to temp (get the stat open), bleed it and let it cool down and then repeat a few times. If you don't the air will stay in.

Another possibility is that they have fitted the thermostat in upside down so that as it gets to temp, it shuts up the radiator. That would explain why its gets cold then very hot. The stat outlets should point up in a shallow V from the front. Alternatively you should be able to feel when they open.

Steve
www.tvrbooks.co.uk

[ridds]

Sounds to me like the previous faults have resulted in head gasket failure and your now pressurising the cranckcase with gas and hence the blowing off of the vent pipe.

Top up your coolant and ensure that it is bled correctly. You can also use a coolant circuit tester to check for exhaust/charge air gas in the coolant circuit.

[weatherboard]

Have a look in the header tank for the rad - is there a brownish sludge in there?

If so it could be the head gasket. When I worked on heavy diesels years back if this happened you got pretty much the same effect as the oil emulsion tended to gum everything up until it was hot enough to act as a liquid again - could be blocking the stat.

I would also agree with the other post - if the breather pipe is blowing off then the crankcase is becoming pressurised and that is not good.

Jon

[big g]

Thanks everyone...useful comments
I bled the system last night (also noticed the lower part of the rad was much cooler) but after 1 hour on the M4 this morning the fans were really struggling to contain the temperature and wisps of steam joined the fun!, not sure but i think a rattle had developed also.

Very stressed and hot....me and the cerb

Dealer has collected her just now....so will let you know the news.
Made worse by a Chim tearing past my office as I type :-(