Coolant system bleeding and coolant turned from blue to clear (1.4 mpi 8v)

[anewman]

Hi, I am asking in regards to my Sister's Fabia 1.4 mpi 8v. I was wondering what the correct bleeding procedure was for the coolant. I tried running the engine with the cap off but eventually the level of coolant in the header tank increased from the minimum mark and went right up to the top of the tank starting to overspill before I rushed to put the cap back on, and the radiator fan turned on at this time. I think she had the water pump replaced and the garage put in blue coolant not too long ago, at most 6 months, but this has now turned clear, it really does look like water. There was plenty of "mayonnaise" under the oil cap but the car has been used for short journeys to work and back so I think that could be the cause. There's no obvious signs of oil in the coolant (just a light oily film on the surface of the coolant). Thanks in advance

[Tom_vRS]

Is the thermostat stuck closed?

Its a pretty standard car to bleed, just make sure the heater is on hot.

[KenONeill]

Blue coolant? I thought the recommended coolants were pink.

[anewman]

Is the thermostat stuck closed?

Its a pretty standard car to bleed, just make sure the heater is on hot.

The car seems to get up to the middle of the temp gauge ok and the top hose gets hot, so I would guess it's ok.

Blue coolant? I thought the recommended coolants were pink.

Yeah I think she used a crap garage to replace the water pump who thought the blue stuff would do, they also broke the plastic engine cover.

[ap0gee1978]

Yep, should be pink / orange. Procedure is to fill to max, start engine and run at fast idle with expansion tank cap off until rad fans kick in and stop again. Then turn off engine, top up if required to between max and min, and put expansion tank cap back on. It's worth checking the level one more time after you've been out for a bit of a drive and the engine's had a chance to cool.

[anewman]

Thanks for all the replies. "Mayonnaise" has quickly reappeared under the oil cap. Tried bleeding the coolant system again from cold, heater fully on, level on the ground - again the fan came on and at the same time the coolant shot up and overflowed. The car stays in the middle of the temperature gauge when driving and there's no sign of overheating. Also when removing the coolant cap there doesn't seem to be as much pressure as I would have expected. Could this still be a sign the thermostat is stuck closed?

[Jim H]

I have just read that you should never mix the pink stuff (G12/G12+) with normal Blue/Green stuff as if you do, it reacts together and forms sludge which can block pipes and passageways. Does anyone know why this pink stuff is better than the blue/green ethylene/Propylene glycol?

[anewman]

I think I have read g12+ solved the problem of it turning to sludge with other coolants (earlier variants, g11 and g12 did cause sludge). It is supposed to be a "life long" coolant and I have read somewhere it doesn't turn the header tank opaque like the blue stuff does.

[KenONeill]

Other than "because G12[+] lasts significantly longer than the 2 years of a "normal" glycol coolant, no.