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Discussion Starter #1
I have had a good search, but no-one seems to have had the same situation as I have!

The temperature guage went up, and the red lght came on when I got stuck in an icebound car park in December (ish). Since then I have kept a close eye on the coolant and oil situation - everything is fine (no gunge, and no loss of coolant)

The thing is, the temperature guage is only steady if I run with the heater on hot and the fan on 1. If I am driving up a long, long hill, or give it a strenuous thrash, the guage starts to climb. If I click the heater fan to 3 or 4 for a few seconds, the guage goes back down again.

(Running with the heater on isnt too bad in the winter, but I dont want to be doing it in the summer, and I want to get to the bottom of this anyway!)

Please tell me it sounds like an air lock!
 

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I have had a good search, but no-one seems to have had the same situation as I have!

The temperature guage went up, and the red lght came on when I got stuck in an icebound car park in December (ish). Since then I have kept a close eye on the coolant and oil situation - everything is fine (no gunge, and no loss of coolant)

The thing is, the temperature guage is only steady if I run with the heater on hot and the fan on 1. If I am driving up a long, long hill, or give it a strenuous thrash, the guage starts to climb. If I click the heater fan to 3 or 4 for a few seconds, the guage goes back down again.

(Running with the heater on isnt too bad in the winter, but I dont want to be doing it in the summer, and I want to get to the bottom of this anyway!)

Please tell me it sounds like an air lock!

What I would do first is make sure that water pump is fuctioning properly, got a feeling that may be buggered, has that been changed at all in the past?

Take a look at the expansion bottle, you will find a small return hose connected to it, take off the expansion top, have someone rev the car up and see if any coolant is shooting through that hose down into the tank. If not then the pump is knackered mate.

Also check the state of the Viscous fan........start the car, let it idel, grab a peice of card and roll it up, stick it into the fan blades, if it stops easily and there is no resistance at all then that needs to be changed.
 

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its possible youve damaged the head, do a complete coolant change and flush the engine, change the thermostat at the same time and see if it clears up
 

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Discussion Starter #4
new pump in last weekend, didnt put the thermostat back in - just out of interest! made no difference at all
 

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new pump in last weekend, didnt put the thermostat back in - just out of interest! made no difference at all


Re-bleed the system again mate.

Did you check the fan?

If all else checks out then as Ron suggested, may be a gasket problem.

I would get a sniff test down.
 

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I'd advise bleeding the cooling system first

How to bleed the cooling system.
1.Jack the front of the vehicle up onto stands as high as possible,
2.Turn the ignition on,engine off,heater on fan setting 1 and temperature fully hot,
3.Remove the rad cap/expansion cap,remove the bleed screw from the rad and IF you have them the bleed screw(s) from the thermostat housing/top hose, return pipe or EGR thermostat.
4.Fill the radiator up and keep pouring till there are no more air bubbles coming out from the bleeds, when good then install bleeds and tighten down(don't snap them),ensure the rubber O-rings/seals are still on the screws/on the bleed holes.
5.Suck some water out so it's not full to the brim, replace the cap and then start the car. Run her up and check for heat from the vents when warm and check if over heating still persists.
6.If good then check the water level again in the morning when cool.
 

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Discussion Starter #7
done all of that now. Sniff test showed nothing in the coolant. Had the front end so high off the ground that I needed a box to stand on just to see the radiator filler!

Head gasket is being replaced tomorrow!
 

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done all of that now. Sniff test showed nothing in the coolant. Had the front end so high off the ground that I needed a box to stand on just to see the radiator filler!

Head gasket is being replaced tomorrow!


Dude, if the sniff test was clear, why change the head gasket mate?
 

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Discussion Starter #9
I have changed everything else, and I noticed the block was under pressure when I took the oil filler cap off. I reckon exhaust gasses are leaking into the block?
 

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I have changed everything else, and I noticed the block was under pressure when I took the oil filler cap off. I reckon exhaust gasses are leaking into the block?


If the sniff test was done and it was negative- I would not change the gasket mate.

Did you check the viscous fan?
 

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Is the radiator getting hot all over?

And when looking into the top of the radiator with the cap off and you are holding the revs up is there coolant flowing into the expansion tank from the small hole in the side of the neck.
 

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Discussion Starter #14
Having read the two previous posts, I thought I should check a few items again before taking the head off.
Water pump ok, fan working ok - however - the radiator wasnt hot all over the core. it was like this



Flushing it has made the core warmer over a SLIGHTLY bigger area, but not much.

So we have spent the morning flushing, draining, cleaning, draining, filling, bleeding - all to no avail. No improvement. Temp guage still only central if the heater temperature is on full, and the fan is on position 1.
 

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Your rad core is silted/blocked up,I had a renault clio diesel that had exactly the same problem and I flushed and flushed the rad to no avail.I got a new rad and fitted it and problem was gone,what was interesting was how heavy the old rad was compared to the new so I broke the old one up and it was full of hard packed silty rust.My electric cooling fan would not work or run because the inbuilt switch at base of rad was getting no heat.Exactly same symptoms as you,steady driving all ok,push it a bit and excess heat build up.
 

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Discussion Starter #17
This is starting to get to me now. New radiator on today - and no difference!

So - a new water pump, no thermostat at all, new radiator and the guage still spikes under load!

:mad
 

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This is all a bit odd !!,has the car ever boiled over ? chucked any water out ?.If you run it with the cap loose on expansion tank and get it hot does it put some water out ??.All these new parts and the sniff test not showing anything. Can you be sure that the gauge does not have a problem ??
 

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Discussion Starter #19
it got hot once, but didnt boil. It isnt using water. Sniff test showed nothing in the coolant. Oil filler is nice and oily. Guage responds to the heater fan being switched on - when the guage shows a temperature rise, the blower clicked onto 4, the temperature drops back to bang in the middle again!!!!!!!!!!
Top hose is hot, bottom hose is cold. Temperature drops across the radiator.
New water pump. New radiator. Thermostat removed.



?????????????????
 
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