coolent

[nigel0024]

my audi a4 18 t started blowing cold air then the tempature level went from 90 to nearly of gauge can anyone give me reson why

[Boardboy]

Nigeloo24 Is the temp gauge up over 90 all the time & Doe's it over heat? Is the expansion tank still pressurized after a lengthy park up?
The reason I ask (and I hope I am wrong) if the head gasket was leaking the hot gases pump in to the cooling system. The heater matrix is at about the highest point in the system and thats where the gases collect. Hence no hot air as there is no coolant in the matrix.
You can get the coolant system checked for hydro carbons that is one way to tell if the headgasket is going/gone.
Good luck and fingers crossed!
regards Boardboy

[MalcQV]

Something similar just happened to my Passat with the Climatronic A/C. The temp gauge went right up. I was convinced it was the thermostat. It turned out to be the water pump.

I have replaced water pumps on many cars, the last one (prior to the VW) was changed because it was screeching.

[dolphinfreindly]

can you see and oil in the water, or emulsification (looks like mayonaise) in the oil?

[Marc97]

Oh dear

Sounds like a head gasket.
If your temp gauge comes up pretty fast but the heater is still blowing cold, check the water pipes for pressure. Have a feel and if the are hard and you cannot open the water filler cap without it blowing everywhere then you will need to have the head gasket changed and more than likely, a head skim (highly recommended).
Shop around for prices as some places overcharge by huge amounts.

[MCCLATCHIE]

Hi I had this on my A4 1.8t 2001 The gauge was showing around 100 deg
and I got a warning on my dash.
The state is in a plastic housing all in one new one is around £45 + RED antifrweeze all abount £60.
The state has a sensor in the housing which is 15hm 100 degs this sends out a warning . There is now a Haynes for 2001-2004 models easy job to do. Under the front is the fan state pull back the u-clip pull out state the coolant will drain out.
Remove coolent tank then drive belt just sprung loaded pull back using a 17mm spanner remove belt take note of pattern for when you refit.
uplug and remove trottle value four screws, Look for uclips and remove all pipes unscrew the state housing refit all parts, refill coolant and run the engine with out the correct tools it may take sometime to get all of the air out.
The was at state on Ebay going for about £5.0

"Good luck" I always replace the small cheap parts first you no there done then Must deals what around £75 to £100 an hour now.