Hi,

I wonder if anyone can help. I've had my 2001 1.9TDi Octavia for about 6 months and it keeps overheating after about 30 miles or so gentle driving. I can drive it hard for 10 - 15 mins no problem but after about 30mins even gentle driving (I'm talking 65mpg motorway gentle driving) it creeps towards the red and loses water.

I've changed the stat, had the pump changed but still no joy.

The radiator top pipe gets hot, as does the heater matrix inlet pipe but neither outlet pipe gets hot and there is no hot air from the vents. I've flushed through the rad and heater matrix, I've squeezed every pipe I can see until my arms are nearly dropping off, any possible ideas? I was thinking maybe an airlock (is there a bleed valve I can't see?)

I've searched the forum but can't see anything specific (other than the doom and gloom of a head gasket) but don't think that this would explain the lack of circulation.

Any ideas ? ? ?

Edited 25 September, 201015 yr by TallChristoff

Cold bottom hose is usually caused by incorrect refilling, blockage, stuck thermostat or disintegrated water pump impellor.

Did you fit the thermostat the right way up? Is there any white smoke out of the exhaust? Coolant in the oil?

If the bottom hose stays cold it definitely has air in it. I've never known a blown head gasket to cause an unmovable air lock.

You seem to have tried all the things that normally move trapped air in the cooling system, however it is essential when you refill the system to let the engine idle & warm up with the header tank cap off. After the top hose starts to warm up hold the revs at about 2500 rpm for 3 or 4 minutes with the cap still off. Top up & start squeezing the bottom hose with the engine at idle., & repeat the procedure.

Thanks Paul,

There's a bit of white smoke on start up, I'll give it another go as I've not done the revving it bit. Is there any way of controlling the throttle from the engine bay so I can keep an eye on it? I can't see anything moving when the other half revs it

Thanks again.

Edited 25 September, 201015 yr by TallChristoff

It helps if you can get someone to sit in the car holding the rpm's up while you add coolant.

Hi,

I wonder if anyone can help. I've had my 2001 1.9TDi Octavia for about 6 months and it keeps overheating after about 30 miles or so gentle driving. I can drive it hard for 10 - 15 mins no problem but after about 30mins even gentle driving (I'm talking 65mpg motorway gentle driving) it creeps towards the red and loses water.

I've changed the stat, had the pump changed but still no joy.

The radiator top pipe gets hot, as does the heater matrix inlet pipe but neither outlet pipe gets hot and there is no hot air from the vents. I've flushed through the rad and heater matrix, I've squeezed every pipe I can see until my arms are nearly dropping off, any possible ideas? I was thinking maybe an airlock (is there a bleed valve I can't see?)

I've searched the forum but can't see anything specific (other than the doom and gloom of a head gasket) but don't think that this would explain the lack of circulation.

Any ideas ? ? ?

Are you sure it is actually overheating and not just a faulty temperature sensor ???

Also is the radiator cooling fan coming on when the temp rises above normal ???

And have you checked the radiator core for a blockage ???

Yeah I'll have to give it a go tomorrow, it's just started tipping it down and I the garage is full of junk as usual.

Thanks Paul,

There's a bit of white smoke on start up, I'll give it another go as I've not done the revving it bit. Is there any way of controlling the throttle from the engine bay so I can keep an eye on it? I can't see anything moving when the other half revs it

Thanks again.

No your car is drive by wire so you do need your "other half" to help.

Check the pump. With the reservoir cap off, raise the revs to about 3000. You should see a steady stream of water coming out of the return pipe to the reservoir.

Whilst the engine is warming up, you should get flow through the heater matrix. If the heater matrix outlet pipe is cold, then you have no flow. The radiator isn't the problem because there is no flow through the radiator until the thermostat opens.

Thanks again for all the ideas,l finally the rain has stopped and my partner was free to lend a hand (or right foot), so I've given it a go.

Got the car up to temperature with the expansion cap off and got her to rev it to 3,000 - water seems to be flowing through the expansion bottle but not a huge amount - then dropped back to 2,500 whilst I squeezed the top hose and heater matrix in and out pipes, in a massage style of squeeze and also a squeeze it shut and then release it style.

After about 10 minutes of this my arms could take no more (I know I'm a wimp), quite a few bubbles and gurgling, tried bursts of higher revs but still no joy, no heat from the air vents, which i assume means it's still airlocked.

Any other hints or tips should I go to the gym for a couple of weeks and give it another go or should I admit defeat and take it to the menders. :(

You need to squeeze the bottom rad hose not the top.

You need to squeeze the bottom rad hose not the top.

Yeah, sorry, did that loads too in an attempt to shoot water through the matrix, might try and bypass the matrix with a bit of copper pipe but the clips are a bu??er to get to and I really dont want to damage the matrix connections.

Edited 27 September, 201015 yr by TallChristoff

I take it that the bottom rad hose stayed cold? Are you sure you put the thermostat in the right way up?

I would try flushing & back flushing the heater matrix & rad next. You'll get water everywhere, but I think it's the only way your going to know for sure that both are flowing correctly.

I would swop places with your partner because its obvious your not squeezing correctly

Tel

Could there be a blockage in the engines water channels somewhere?.

We had a very similar fault to this recently, unfortunately it turned out to be the head gasket casuing the airlocks, the only other thing you can try is reverse flushing the cooling system ?

You could try removing the thermostat, which will help to get the coolant flowing.

I'd also get a dye block test done at your mechanics, that'll reveal whether it's a blown head gasket causing the problem.

Turned out to be a pitted head, skimmed and new valves etc for a pretty reasonable £500 - thanks for all the help and advice