Overheating (according to gauge) minutes after starting - KV6

[T-Cut]

Originally Posted by SD1too

This is an error made by and copied from Haynes. No hoses should be detached from the expansion tank.

What RAVE actually says is this:

"Release expansion tank bleed hose from clip on top hose."

This is simply so that the narrow bore bleed hose does not restrict movement of the expansion tank when it is raised.

Simon

A trivial detail. Since the pressure cap is off, it really doesn't matter if the bleed hose is detached from the neck.


TC

[T-Cut]

Originally Posted by ashy90

By the time it was reading approx 55 the gauge was over half way.

I guess by 'over half way', you mean the gauge needle was above the '9 o'clock' i.e. the 'normal' position. If so, then it has somehow lost its calibration. The gauge is calibrated such that at 75C, the needle just hits the 'normal' mark. It will then stay in that position (the 'buffered zone') until it reaches 115C. At 116C the needle will begin moving up and rapidly hits the red light at around 120C.

It seems your gauge is over-reading, so it reports an overheat when the temperature is in the normal running area. Perhaps a T4 specialist can adjust the calibration? I know it is possible to alter the settings of the 75-115C buffered zone, so it might be possible to fix it.

TC

[Blink]

Originally Posted by T-Cut

You need to do it by the official MGR bleeding proceedure, which is given in RAVE and the Haynes Manual:

1. Remove the bleed screw in the hose located between the engine and air filter.
2. Detach the (narrow) hose from the side of the header tank filler neck.
3. Remove the bolt securing the header tank to the radiator top and swing the tank backwards so you can unhook the side mounting pegs.
4. Lift the header tank as high as it will go (about 5 inches), ensuring none of the plastic hoses are kinked.
5.Slowly fill the cooling system, keeping the header tank full to just under the neck, until coolant emerges from the bleed hole as a steady stream.
6. Replace and tighten the bleed screw.
7. With tank still raised, continue filling the system until coolant level settles just below the filler neck.
8. Lower the header tank and refit it usng the locating pegs and mounting bolt.
9. Refit the narrow hose back onto the tank neck connector.
10. Leave the pressure cap off.
11. Ensure the aircon system is off.
12. Start the engine and have an assistant run it at 1500-2500rpm.
13. Be prepared to top up the header tank as the engine starts and maintain the level just below the filler nek.
14. When the coolant level starts to rise due to heat expansion, refit and tighten the pressure cap.
15. Maintain a fast idle until the cooling system gets hot and the radiator cooling fan trips on.
16. Allow the fan to reduce the temperature until it switches off, then stop the engine.
17. Allow the engine to cool completely, preferably overnight.
18. Check the work area for leaks.
19. Check the coolant level and adjust it to the MAX marker.

Avoid adding your own steps or wavering from the official method.

TC

TC - is this also the refill procedure to use after a complete draindown (for a KV6 coolant change)

[T-Cut]

Originally Posted by Blink

TC - is this also the refill procedure to use after a complete draindown (for a KV6 coolant change)

Yes, it assumes the cooling system's empty or that you just want to top up and bleed out any trapped air. I quoted the refill (or top-up) and bleed method from Haynes but omitted the drain down part. You can leave the small (8mm bore) hose attached to the header neck if you want. It makes no difference as long as you can lift the header by about five inches to increase the hydrostatic pressure.



TC

[Phil-T4]

Originally Posted by T-Cut

I guess by 'over half way', you mean the gauge needle was above the '9 o'clock' i.e. the 'normal' position. If so, then it has somehow lost its calibration. The gauge is calibrated such that at 75C, the needle just hits the 'normal' mark. It will then stay in that position (the 'buffered zone') until it reaches 115C. At 116C the needle will begin moving up and rapidly hits the red light at around 120C.

It seems your gauge is over-reading, so it reports an overheat when the temperature is in the normal running area. Perhaps a T4 specialist can adjust the calibration? I know it is possible to alter the settings of the 75-115C buffered zone, so it might be possible to fix it.

TC

My thoughts are the same, the IPK eeprom holds the data for the temp sensor steps, maybe this area has got corrupted.
Unfortunately its not an area that the T4 writes to, so a virgin eeprom and recode should sort it.

Easily confirmed by throwing in another IPK (ignoring any errors) and running the same coolant temp monitoring.

[T-Cut]

Originally Posted by Phil-T4

Easily confirmed by throwing in another IPK (ignoring any errors) and running the same coolant temp monitoring.

Good idea. If positive, a bit of soldering and a T4 session should do it eh?


TC

[Phil-T4]

Something like that

[cb750chris]

Message sent to the OP, offering help.

Fingers crossed we can eliminate the IPK

[Bolin]

Just a thought, rather than data corruption perhaps there is an issue with the motor that drives the needle?

Does the needle correctly sit at the blue spot when car is stone cold?

[ashy90]

Ok just to update you on this.

I guess I could have got it wrong when I said that the temp gauge was over half way and the temp was reading 55. I really don't know.

The rad fan I tested and was not working at all on any of the 3 speeds. So I had not been able to do anything with the car up until recently. It has a new fan fitted now.

I have drained the entire system, flushed everything. Water flowed ok through the oil cooler (the previous owner had been told this could be blocked). I re-filled the system with a helper following exactly the process listed in this thread. I got to step 12 - running the engine with the cap removed, the coolant in the tank did rise soon after starting the engine. It kept rising and falling, sometimes up to the top and out of the tank. I thought this is probably air being expelled? I put the cap on and began running it up to temp but noticed a weeping hose so I switched it off and I allowed it to cool a bit, tightened hose clip and topped up the tank.
I then ran it up again until the fan kicked in - hot air from heaters, temp gauge a smidge over half way, rad fan kicked in about 104 I think and dropped the temp down to about 90 (roughly). I left it overnight.

The next day I had it running again after checking the level -
Nice hot air from heaters, fan cut in just over 100 (I cant remember exactly) and reduced temp to approx 90. But yes the gauge sits at a smidge over half way. Is this a concern?