coolant system circulation

**Col** · 19-11-2009,07:04 PM

Your head gasket has failed and it will only get worse.

115hp AJM TDI's are notorious for this.

The mode of failure is not that of what is considered a classic head gasket failure and can be very hard to detect.

Take it to a specialist to confirm the diagnosis. A normal garage will probably go along the stat / water pump route, a specialist won't, they will go striaght for and investigate the HG.

**FLENG2008** · 19-11-2009,07:11 PM

ok ive had a sniffer what else can i do to check the gasket?
thanks

**herby0001** · 20-11-2009,10:42 AM

Probably best then to drop the rad, flush it out with a hose. You could also check for blockages by putting the hose into a coolant pipe and see if it flows through the engine block too. Maybe narrow it down that way?

**FLENG2008** · 20-11-2009,02:33 PM

ok thanks

i was gonna give that a try before HG anyway

any other suggestions? or options i could try before i bite the bullet or if theres any way i could check if it is the gasket before i try more guess work

thanks for the replies

**AJB** · 23-11-2009,02:30 PM

Originally Posted by FLENG2008

...and the fresh coolant thats was put in recently has now turned a bit rusty coloured

Was it the right sort of coolant that was added? If the factory G12 (pinky purpley colour) is mixed with the wrong sort of stuff, I think it can form brown sludge... Could that be blocking up the thermostat etc?

If so, then it might just need draining, a complete flush, and then filling with the correct coolant.

**FLENG2008** · 23-11-2009,02:36 PM

yes it was g12
im gonna try a flush and see but i think its more than that, for some reason it doesnt seem to circulate fully, what should i use to flush it out with? i dont think its the head gasket but im running out of other options now

ill try a flush and im getting a block test done to see if that shows anything

**AJB** · 23-11-2009,02:43 PM

Originally Posted by FLENG2008

yes it was g12

And was it definitely G12 that was in there before? I've just got a feeling that you get brown sludge if they mix, and I can't quite see why else your new coolant would have gone rusty coloured.

Originally Posted by FLENG2008

what should i use to flush it out with?

Someone else might have a better plan, but if it was me I'd just drain, fill with water, run for a bit to flush it round and repeat until the water stays clear. Then drain once more and fill with the correct coolant.

Don't know if the heater control on these is in the water flow or air flow, but might as well have the heater on hot whilst you're doing it.

**AJB** · 23-11-2009,02:58 PM

Just to add, I'd run it up to temperature with just water in, so that the thermostat gets to open and the water gets to flow through the radiator too.

**FLENG2008** · 23-11-2009,03:09 PM

alright thanks for the replys i will try that..

**FLENG2008** · 25-11-2009,02:03 PM

i havent flushed it yet but i have noticed i deff have a circulation problem

am i right in thinking that the flow of the coolant is supposed to:

start in the engine and warm up
then the thermostat will open and the bottom hose gets hot and then the rad gets hot and pushes the cooler water back into the engine and so on..