10 replies to this topic

[j0-rdan]

Overheated three times in the last 2 days, found that with super slow driving it was cooling down, but then every time I turned the lights on it would shoot back up, can anyone tell me if that is just how hot engines are or do I need to look at something specific?
I am changing the cylinder head in the next few days so hoping the head gasket change etc. should fix it.
Thanks

[Wil_h]

Sounds fan belt related to me. Check for condition and tightness

[j0-rdan]

Sounds fan belt related to me. Check for condition and tightness

Ok thanks, don't know if this changes that but the fan seems to be turning alright?

[Boycie]

Ok thanks, don't know if this changes that but the fan seems to be turning alright?

Hi mate, do you have a side-mounted rad/ fan or a front mounted (mpi) one?

Because if you can turn the side-mounted, belt driven fan by hand, the fan belt is too loose and invariably slipping. The waterpump is 'underneath' the fan so this may cause your problem.

[j0-rdan]

Hi mate, do you have a side-mounted rad/ fan or a front mounted (mpi) one?

Because if you can turn the side-mounted, belt driven fan by hand, the fan belt is too loose and invariably slipping. The waterpump is 'underneath' the fan so this may cause your problem.

My radiator is side mounted, can I check the water pump somehow?
I was also thinking today its almost as if with the lights on the temperature readings are getting messed up and so the thermostat isn't opening at the right times? I did change the thermostat recently so that shouldn't be the problem. Is it possible the temperature sensor is messed up?
Any ideas would be helpful as this is depressing me now I have finished uni exams and have nothing else to worry about!

[guesstimator]

Does the temperature increase instantly when you switch the lights on and then decrease the same way once you switche them off?

If so then it probably just a bad earth on the intrument/s

But in any way, check if the engine is really overheating and it's not just an erroneous reading.

[j0-rdan]

Does the temperature increase instantly when you switch the lights on and then decrease the same way once you switche them off?

If so then it probably just a bad earth on the intrument/s

But in any way, check if the engine is really overheating and it's not just an erroneous reading.

No it just slowly creeps back up, it definately is actually getting hot as when I pull over water is boiling out of the radiator onto the floor

[guesstimator]

definetly not normal behaviour....have you done any work on the car or has the problem simply started suddenly?

you could check for bubble in the rad, which would imply hot gases getting blown into the cooling system trhough damaged head gasket .
Check if the thermostat opens. from cold keep a hand on the top rad hose and wait for the engine to warm up. eventually the thermostat should open and the pipe becomes quickly warmer. if not that's the problem.

Is the fan belt in good nick...as suggested if you can turn the fan by hand then its on the loose side.

is the fan the right way round?

Do you know the history/condition of the water pump? milage?

Does it get hot straight away or does the temp very gradually but inevitably increase? if so sould be a leaking rad cap or other leak in the system, which gradually empties increasing temps.

Any oil in water or water in oil?

just a range of standard checks to carry out before wipping the head off

[guesstimator]

p.s. the thermostat is a wax based type and is independent of electrics

what thermostat temp did you fit?

Edited by guesstimator, 26 May 2010 - 09:43 PM.

[j0-rdan]

definetly not normal behaviour....have you done any work on the car or has the problem simply started suddenly?

you could check for bubble in the rad, which would imply hot gases getting blown into the cooling system trhough damaged head gasket .
Check if the thermostat opens. from cold keep a hand on the top rad hose and wait for the engine to warm up. eventually the thermostat should open and the pipe becomes quickly warmer. if not that's the problem.

Is the fan belt in good nick...as suggested if you can turn the fan by hand then its on the loose side.

is the fan the right way round?

Do you know the history/condition of the water pump? milage?

Does it get hot straight away or does the temp very gradually but inevitably increase? if so sould be a leaking rad cap or other leak in the system, which gradually empties increasing temps.

Any oil in water or water in oil?

just a range of standard checks to carry out before wipping the head off

Ok I will answer what I can now of that list..
I changed the whole engine when I first got the car 2 years ago and since then it has had problens with overheating, I think it has gotten worse recently.
I am unable to turn the fan by hand, but I have ordered a new fan belt anyway. With the amount of mechanics I have had look at my car I would be very surprised if the fan was the wrong way round!
I don't know the history of the water pump. It gets hot gradually over a time of anywhere between 15min-2hrs. I am changing the cylinder head soon for a stage 3 so will be changing the head gasket anyway.
So after this work, if I am still overheating would you suggest changing the water pump? Is that expensive?

[j0-rdan]

I know this is a pretty boring topic so sorry to keep bumping it up, but Im still struggling with it..
My newest question is that when I tried guesstimators advice on checking the thermostat (feeling the radiator hose get warm when the temp increased) everything was fine. So should I still be thinking about getting a new water pump if the water is being pumped round enough for that test to work? As in can a water pump be working at a level to allow some circulation but not enough for long periods of time (>30min)?

Edited by j0-rdan, 28 May 2010 - 11:07 PM.