Toledo coolant problem

[bondwithme]

Hi,

My tdi is doing strange things the rad is always cold along with the bottom hose but the temp gauge reads 90 and the heater gets hot in 5 - 7 mins. Also the coolant level drops from max to min under normal operation but returns to max once the pressure is released, also it retains pressure for 72 hours!

The power is good with 52mpg no apparent coolant loss and I have changed the coolant, stat & temp sender, and it never overheats

pls

Thanks

2001 tdi 110bhp

[Crasher]

That is because it takes ages for a diesel to get hot enough to open the thermostat.

[bondwithme]

That is because it takes ages for a diesel to get hot enough to open the thermostat.

hi,

thats as maybe but this happens even after a 100 mile round trip they don't take that long do they?

[Crasher]

If the heater is on and in this weather, quite possibly. When I service a TDI, I always make sure the fan(s) work and this can take sitting in the workshop for twenty minuets revving the engine at 3500rpm in this weather. There is the possibility of water pump failure causing a reduction in flow and this will not show on the gauge until the engine reaches 117 degrees. I have seen this on many VAG products of the last decade, you can sit and watch the temp readout on the diagnostic computer and it will say 76 when the gauge says 90 and the gauge still says 90 when the computer says 117, then suddenly the gauge goes up. Personally I can’t see the point in a gauge with such a ridiculous display characteristic.

[bondwithme]

Hi,

You make some very valid points and I agree the gauge is crap! But what about the coolant levels going up and down? also I have checked the temp in the expansion tank with a digital thermometer and it never reaches 80 c even after a 40 mile run at 70mph. Pretty sure on the pump all seems secure and intact as best i can feel via the stat hole and the water pumps via the bypass back into the ex tank with no problems + heating is very good

[Crasher]

Odd symptoms yes but if it is not overheating and the flow seems good with the heater output I would monitor it and see how it goes, I don’t think your head gasket is at fault from what you say.

[bondwithme]

hi,

all sorted used k-seal to fix expansion tank water issue level now stable, then flushed system and refilled with g12 rad and bottom hose nice and hot when heater on 18-20c anything above that and they go cold so you were right about the heater thing.

Still have a cold start problem even with new glow plugs so any further help would be great.

Thanks in advance for all your help