A4 Leaking Coolant

[Brass]

Hi all,

I have an A4 1.9 TDI 130 Bhp 2004 that's leaking engine coolant badly. I have tried everything but cannot find the source of the leak. The harder I drive, the faster the coolant leaks. For example Drive easy for 50 miles = 1/4 litre coolant, Drive hard for 50 miles = 1 and 1/2 litres. Basically it emptys itself when driving hard. I've already replaced reservoir bottle and cap, water pump, thermostat and seal, plastic seal connection at rear of block, i've tried bypassing the heater rad, changed all hoses and clips. There is no sign of a coolant leak anywhere under the bonnet. I'ts been like this now for almost a year. It doesn't overheat as long as you keep it topped up as soon as the coolant low light comes on in the dash ( I'm running on water with the last while, the coolant was getting too expensive). The engine oil looks normal, recently changed. There is no sign of water coming from the exhaust. I'm thinking the head or head Gasket but don't realluy want to touch it until i'm positive that this will fix the problem. Any Thoughts?????

 

[kite]

Have the coolang.system pressure checked

 

[Brass]

I've also had the cooling system pressure tested and there was no pressure drop. Also just to note that the leak is only present when the engine is running.

 

[kite]

Have it sniff tested. That will test for hydrocarbons in the coolant and prove a head gasket failure

 

[marktdisport]

just out of curiosity when was the water pump last changed m8... is there any chance it's leaking from the little tell tail hole ive seen this before but it also leaked after a good run when the engine was swithed off, if i remember it was a b5 tdi i done this job on and water pump cured it

 

[AU01 A4]

Have You Checked the coolent bleed valve?

 

[Brass]

Thanks for your replies....
Water pump was changed about 5 months ago? Absolutely no signs of water around the pump.
Where is the coolant bleed valve located?

 

[Turkster]

Head Gasket

 

[AU01 A4]

sorry for the late replay, been on the road,
see link
Coolant bleeder screw PN request # 2... - AudiWorld Forums

 

[moggie93]

Same as turkster.. Sounds very like the head gasket has gone.I've recently went thru the same with my 1.9 tdi mk4 golf.. Tried many new parts and all that was left to do was the head gasket.. Not had any more coolant problems since..
M