Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[arronsweeney]

does anybody know where the valve is to empty water system on 3 litre elite

[Auto Addict]

Looking at the car from the front, it's at the back of the radiator, bottom right.

[JasonH]

Red thumbscrew.

Only will drain half the system (5 litres). To get the rest out is more involved.

[Markjay]

It just occurred to me, perhaps they were referring to 'thermoswitch' rather than 'thermostat'? A thermoswicth is a temperature sensor that activates the fans when the engine temp goes up. If it isn't working properly, what you will see is that the car behaves perfectly normal when driven mildly on motorways, but as soon as it is left to idle it will boil over.

[Markie]

it may possibly as Dave is thinking, be oil cooler failure. Time consuming but do able at home if time allows.

Thermostat is not hard to do but involves a fair amount of stripping to the valley, where oil cooler also is.

incidentally - for my own knowledge - what sort of thing causes over pressurising?

[Admin]

Overpressurising is caused by air getting into the system.

As you know the coolant system is pressurised under normal operation.
However if there is a small leak in the system, then the following can happen...

A small leak can allow water to be pushed out under pressure...eg engine under load.
However, when that pressure is reduced, ie. when the load is reduced then a vacuum is formed at the leak.
This then sucks in air...

When air is heated it expands and takes up more "space" than water.
Get enough air in the system (and it doesn't require much) and the system becomes overpressurised causing overheating problems.

Dead giveaways are rock hard coolant pipes pipes and a "hissing" from the coolant cap as it tries to vent off the excess pressure.

If you suspect this, BE VERY CAREFUL when loosening the cap as the water will be above boiling point and under tremendous pressure.  
Use a towel and VERY gently turn the cap so it just starts to release pressure. Turn it too quickly and the cap will blow straight off and soak you in boiling water!!
This has happened to me and it is very very unpleasant!

Now move away and leave it for a few minutes to allow the pressure to vent off safely.

The most common cause of air getting into the system is a a split in the heater bypass valve. As many of you know, that is situated at the back of the engine, towards the drivers side.

Don't try and drive the car unitl the problem is resolved. The pressure and heat can cause failure of other components very quickly.

[Markie]

So Dave - sorry for the thread Hijack  

I can clearly see my vectra is over preassurised - it blew top hose off even when it was tightley jubileed.

Running car for 5 minutes has coolant shoot back out expansion tank ...

Car as you know had oil cooler failure. But when i got the car in its post cooler failure stat the bottom hose was blown straight off. Again sounds like overpressurising.

So can over pressurinsing cause oil cooler failure and perhaps i have fixed the effect but not the cause.... :-/

[Admin]

Markie, yours is almost certainly overpressurising due to the coolant being unable to circulate.
If you block the system, you very quickly develop a heck of a lot of back pressure that has to go somewhere...

[Markie]

Markie, yours is almost certainly overpressurising due to the coolant being unable to circulate.
If you block the system, you very quickly develop a heck of a lot of back pressure that has to go somewhere...

dam ...i was looking for an easy fix