Overheating, even in winter

[Black Beauty]

Good Morning everyone,

My little baby has what only be described as an overheating problem which has begun to irritate me enormously.

Basically, on the commute to work which is a 60+ mile round trip to Croydon and back from Guildford, a couple of times a week, every so often she will spit out between 1 - 2 litres of water from the over flow pipe on the expansion tank either during or at the end of the journey depending on length and how hard pushed. The journey is about 2/3rds motorway with the rest fast town driving, ie not stuck in standing traffic for too long. Problems appear to start as soon as I come off the motorway and sit at a traffic light, since the temp gauge rises and if I don't move within a minute or so, the fan kicks in and if I stay there for any length of time, the above will repeat itself endlessly.

Curiously it doesn't appear to happen each journey, and now I don't use her because its becoming a right royal pain in the backside, as I am sure you can imagine.

Back in the summer I had the belts and pump replaced (Porsche parts), along with thermostat and fan switch as well as a radiator flush because she spat the water out then occassionally, now she seems to do it with much greater frequency.

To my thinking if there was a problem with the radiator would that not have shown up on the radiator flush?

This problem has irritated me so much over recent months, that I am seriously considering selling her. A few of my mates tell me not to be so silly, because she is in such good nick and has the genuine low mileage seen below, but I'm at my wits end as I've spent a lot of money on her last year and 3 cars is becoming increasingly expensive.

Any advice, would be greatfully received.

Thanks in advance
Spence

 

[997GT3_KO]

Could it be a head gasket problem...?

 

[Black Beauty]

There's no water in the oil and the cap was expansion cap was replaced too - forgot to mention those.

 

[Fred Hindle]

Possibly time to replace the thermostat.

Cheers,

 

[pauljmcnulty]

Mine did that and it was cured by the indie simply bleeding it properly. Took a couple of goes, jacked up at the front.

 

[944Turbo]

I would guess a tiny coolant leak somewhere resulting in the level dropping enough to get air in the head and create the symptoms of it not being bled properly. I fit has been topped up and bled does it behave for the next 100 miles or so.
Tony

 

[Black Beauty]

ORIGINAL: pauljmcnulty

Mine did that and it was cured by the indie simply bleeding it properly. Took a couple of goes, jacked up at the front.

I really do hope that it isn't as simple as that - that is a rather basic mistake for the Indie to make.

Is there any way of knowing for sure that its got air in it? Wouldn't the air bubbles rise to the top eventually, or would they just get stuck, somewhere?

 

[Fred Hindle]

If part of the system allows an airlock to occur then it is very rare that the system 'self -repairs' itself. Find a join at the highest point of the system and undo whatever clip is holding it, allow engine to tick over and carefully release joint until water flows out of it. May take a couple of goes and ensure you do it with engine cold - you don't get sprayed with boiling hot water.
You could also try moving the heater control rapidly between cold and hot positions whilst engine is running. This often cures airlocks in the heater matrix.

Cheers,

 

[macandsue]

Take the bleed plug out and run the engine, with heater controls to HOT until water comes out of the resulting aperture ,replace the plug let the engine cool down check your water level and SLOWLY add water to the correct level. If you are new to what is under your bonnet the plug is usually a color and is about the size of a 5 pence on the top and the hole is about 3 Cms dia. This should have bled your system you may need to do it twice. It is about half an hour job most of which is waiting for it to heat up enough to open the t/stat.This can be done with the engine stationary and cold just top up the header tank until the water comes out of the bleed hole, again heater controls to HOT, then screw in the bleed screw a few turns and run the engine until the bubbles stop coming out from around it and then tighten it fully. WARNING this is HOT water be careful. Good Luck.
Mac

 

[pauljmcnulty]

I really do hope that it isn't as simple as that - that is a rather basic mistake for the Indie to make.

Is there any way of knowing for sure that its got air in it? Wouldn't the air bubbles rise to the top eventually, or would they just get stuck, somewhere?

I hope it is that simple! [&:] I wouldn't blame anyone, it's very common for them to need repeated bleeding.

They are notorious for airlocks, and it does spew water out of the vent. My indie did say that it's often a head gasket, they are all old enough to be on their last legs now, but he bled the system thoroughly and it did fix it. I'd certainly look there first, especially as you've had work done on the system that may have left air trapped. Good luck!

 

[Mike_Pollock]

Bleed it! As the guys say minimum 4 or 5 times.
Was at an indie yesterday - he was bleeding a turbo and reckoned all 944s have secret holes to store the air!
Also said lift up the front end, if poss. Bleed screw on early ones is on the top of the elbow on the top of the front of the engine, think its 12mm.
Mike
Edit - mine did the same thing going to the dyno day a few months ago - new cap did it - one for an old style mini was ordered and fitted!

 

[944Turbo]

And read water as antifreeze especially in this weather,
Tony