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[Sir Tigger KC]

Hi All,

My 2.5 V6 has been overheating when the heating/AC is on.  Its fine when climate turned off and when cruising, but gets hot if the climate is on and I get stuck in traffic or slow down ie on a slip road off the motorway.  I think that the water pump is OK as if I bring the revs up the temp drops quickly.

I posted about this before and was advised to fit a new thermostat, which I've done today and have a couple of queries...

1) When I drained the coolant it came out brown! Its only about 4 months ago that I flushed the system and put new coolant in. The oil is clean, but I'm wondering if the oil cooler is gone and that's why its overheating? or a headgasket?

2) I can't get the barsteward bolt back in!!!  I'm guessing that's just perseverance... but any tips will be welcome!

Many thanks in advance for any advice!!

[TheBoy]

is it oil in coolant?  if not, it needs lots of flushing

[Sir Tigger KC]

Not sure to be honest TB, its just brown! I'd expect it to be still abit blueish after 4 months?

[Sir Tigger KC]

Can anyone tell me which operates at higher pressure, (at normal operating temp) the oil or coolant?  :-/

So if say the oil cooler goes... do you usually get oil in water or water in oil?

Thanks

[PhilRich]

If the oil cooler goes you get oil in the water & serious sludging up of the cooling system if left too long!

[Sir Tigger KC]

Thanks for that Phil 

I got the barsteward bolt back in after alot of fiddling around.... its a well named bolt!!! 

I'm going to give the coolant systym a good flush tomorrow to get rid of the brown stuff, and have a bottle of Holts Speed Flush which I thought I'd give a try.  Has anybody used it? Any advice?  :-/ :-?

Cheers!! 

[TheBoy]

Holts Speed Flush is shite. But as you've got it, try it....

[Sir Tigger KC]

Ha Ha righto  Like you say as I've got it, may as well bung it in  Cheers TB 

[humbucker]

i used forte biodegreaser. brilliant stuff. tried and tested by a fair few of us on here now, would recommend it to anyone looking to do a coolant flush 

[Sir Tigger KC]

Just filled rad up with water and took for a quick run up the road.  The heater is still not working and it got hot when I slowed down, I pulled over brought the revs up to about 3000rpm and the temp dropped quickly.

In short the new thermostat has made no difference, I'm now waiting for it to cool down to drain the rad to see what comes out....

Any ideas anyone?

[mrgreen]

sounds like a blocked cooler, are your fans coming on when it gets hot? could be a sensor issue if they're not but either way with brown coolant your radiator is not clean!! if there was oil in there you would see and feel residue in there.

[Sir Tigger KC]

Thanks Mr Green.  Yes the fans are coming on normally.  I'll let you all know what comes out of the rad when its cooled down and I'm going to replace the HBV and flush the heater matrix...... 

[Boatboy]

Any cold spots in the rad? If you have (or did have) a load of proverbial in the system, it don't take much for some of the narrow channels to get blocked, especially (imho)as the auxiliary pump and hose provides a neat pressure relieving bypass behind the rad.


I managed to clear mine a bit by blocking off said hose with a rag and mole grips and revving the engine hard. I still had cold spots though, and the real solution was a known good rad from D-L-K.

steve

[Sir Tigger KC]

Hi Steve,

To be honest its abit of an on going problem, which I've lived with and just not allowed it to overheat.  But now its getting colder I can't live without a heater!!

In the last few months its had a new rad, new fan switchs and been thoroughly flushed out. Now its got a new thermostat....

I don't understand why it gets hot when the climate is on....  :-/

[TheBoy]

Just to test heater, pull vac pipe off hbv...