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[T-rev]

Hi, having problems identifying possible overheating....Drove 104 miles yesterday running fine around 98 degrees, but started rising in stand still traffic....put blower on full (cold selected) which saw the gauge shoot straight up to overheat with warning light coming on....Turned the blower off (still on cold select) and the guage started to drop back down again....No coolant loss, no error codes, Thermostat appears to open o.k first time around 95 degrees....fans coming on and working at both speeds....Fan rad switch changed about a month ago....Totally confused.

[Abiton]

Water pump change history....?

[sandune]

Has any work on the cooling/heating system been carried out recently?
Sounds like needs burping imho

[MutantCav]

98 as a normal running temperature sounds rather high...should be about 90-93 and I though that facelifts ran even lower...as said perhaps you have a water blockage...try flushing it

[T-rev]

Thanks for the replies, water pump changed with belts barely 5 months ago...Do intend to renew coolant to the pink stuff, so hoping the suggested flush, and new coolant solves the problem...It did use to run around the mentioned 90-95, but recent months has shown an increase in running temp???

[Gaffers]

Could be the HBV starting to leak releasing pressure in the coolant system and causing the temp to rise.

[T-rev]

Did consider this, so why i am changing the coolant i am going to renew the HBV valve jsut for the sake of it.

[T-rev]

Happy with the replies and suggestions, what i cant get my head around, is why putting the heating on at its lowest setting with full fan speed would cause the temp to shoot up to red???

[Grumpy]

Happy with the replies and suggestions, what i cant get my head around, is why putting the heating on at its lowest setting with full fan speed would cause the temp to shoot up to red???

Because you selected cold there was no longer a cooling
airflow cooling the heater matrix.

If you want to use the heater matrix as a secondary
radiator then you need to select full hot and max fan
speed. This will put max coolant flow through the
matrix and the max fan speed will give a good cooling
airflow.

I sometimes had to do this on a Peugeot 305 in hot
summer weather.
SWMBO used to get mighty upset when I did this,
once she had twigged why she was getting roasted
by hot airflow in the middle of summer. 

[T-rev]

Thanks Grumpy thats that answered...I will do the HBV and coolant flush/change which hopefully sorts it all out..With any luck i can use the air con on cold without having to keep it on hot to keep the engine temp down.

[Abiton]

Thanks Grumpy thats that answered...I will do the HBV and coolant flush/change which hopefully sorts it all out..With any luck i can use the air con on cold without having to keep it on hot to keep the engine temp down.

While you're doing that, I would at least take your water pump off so you can eyeball the impeller.  You'll get more of the old coolant out that way too. 

[T-rev]

o.k thanks Abiton, comment noted

[amba]

If you intend removing the water pump,try and avoid getting the cambelt soaked in coolant by getting as much out by removing/releasing lowest pipework points first.

[T-rev]

Well i changed the HBV and flushed/renewed the coolant yesterday but it still runs hot....Normal driving still between 95-98 degrees but gauge shooting up to redline/overheating light coming on when at a stand still....No signs of steam under the bonnet, no water loss, fans running and everything else looks normal....Could this be the thermostat, or something else??

[Andy B]

.......Could this be the thermostat, or something else??

It could either be your 'stat is stuck shut-ish or your rad is blocked-ish. Flushing doen't generally clear a partially blocked rad as the flush water will just find the easiest way through. You could use an infra red thermometer to look for cold spots on your rad  :-/ clicky
My 3.0 sits at around 92^o in town & doesn't really move much what ever I'm doing - unless the caravan is on the back & ambient temp is high.