PD115 TDi Engine Overheating problem - First Posting

[Mark7]

I have a 1.9 TDi Sharan (PD115 engine) 2001, 130K mileage which has started to overheat underload. When on long trips - 5 people, fully loaded with roofbox @>80mph on motorways or pulling caravan etc. @>60mph after some time the oil temp gauge starts to creep above 120 degrees and then suddenly the water temp gauge shifts quickly from 90 up to 120/130 degrees C - If I carry on then I lose coolant from the reservoir hose and the warning message comes on, but if I pull back on the accelerator the water temperature comes back. I can effectively hold it on the 'edge' of overheating by adjusting the accelerator.
There doesn't seem to be any loss of power, but I am losing some coolant - only maybe 1/2 a litre every 1000 miles or so.

I have had the water pump replaced and the radiator fane thermoswitch replaced but it has made no difference.

I am wondering if it might be a cylinder head or cyl. head gasket problem from reading some other threads, but I believe it is an expensive job and don't want to have to do it if it isn't the real problem (having already spent >£500 with no solution!).

Has anybody had any similar problems and identified the cause/solution ????

Thanks very much in advance

[deancentral48]

If the head gasket is going then there is alsmost certainly going to be water in the oil in the sump. This can usually be seen as a white froth when you lift the oil topup cap off.

You seem to have a high pressure related problem which is hard to find without surfing the bonnet at those speeds!

I assume that you have checkled all hoses for evidence of leakage; the pressure cap to the water topup reservoir sometimes fails; the water topup reservoir itelf sometimes splits where it is held especially if the coolant has not been changed lately or you have added lots of water without any of the special anti-freeze and the water reservoir has frozen in the recent cold weather and cracked somewhere - it sometimes cracks where held at the side or bottom and sometimes around the thread on the neck; are you adding the special anti-freeze in the correct proportions - it is critical to the corrosion resistance of anything alloy in the circuit - does your topup bottle that you carry with you contain it?

Are there any leaks in the matrix of the radiator?

Is there any evidence of oil leakage around the head gasket area on the outside - clean around with meths or similar and then study it after a run.

You are certainly thrashing it under load and it will repay you to find this problem before serious damage is done.

In the meantime keep the water / antifreeze and the oil up to the required levels - don't overfill as you will blow your seals.

[Mark7]

Thanks for your reply -

When I originally identified the problem (about 5 months ago) I had a pressure test on the cooling system and it didn't show any problems.

It has only had to have some extra water/coolant 2 or 3 times of 1/2 litre or so since then (about 7,000 miles)

There doesn't seem to be any water in the oil - no deposits on the oil filler cap. The coolant was changed/renewed (about 5 months ago) - it does (it didn't have until the last month or so) now has some carbon deposits in it - the reservoir has some soot deposits on its inside surfaces.

Any further thoughts ??

[Col]

Thanks for your reply -

When I originally identified the problem (about 5 months ago) I had a pressure test on the cooling system and it didn't show any problems.

It has only had to have some extra water/coolant 2 or 3 times of 1/2 litre or so since then (about 7,000 miles)

There doesn't seem to be any water in the oil - no deposits on the oil filler cap. The coolant was changed/renewed (about 5 months ago) - it does (it didn't have until the last month or so) now has some carbon deposits in it - the reservoir has some soot deposits on its inside surfaces.

Any further thoughts ??

It will be the head gasket.

Another tell tale is to feel the bottom hose. If it is stone cold, even after a run, it'll be the head gasket as more than likely.

[carbon8ed]

I have a 1.9 TDi Sharan (PD115 engine) 2001, 130K mileage which has started to overheat underload. When on long trips - 5 people, fully loaded with roofbox @>80mph on motorways or pulling caravan etc. @>60mph after some time the oil temp gauge starts to creep above 120 degrees and then suddenly the water temp gauge shifts quickly from 90 up to 120/130 degrees C - If I carry on then I lose coolant from the reservoir hose and the warning message comes on, but if I pull back on the accelerator the water temperature comes back. I can effectively hold it on the 'edge' of overheating by adjusting the accelerator.
There doesn't seem to be any loss of power, but I am losing some coolant - only maybe 1/2 a litre every 1000 miles or so.

I have had the water pump replaced and the radiator fane thermoswitch replaced but it has made no difference.

I am wondering if it might be a cylinder head or cyl. head gasket problem from reading some other threads, but I believe it is an expensive job and don't want to have to do it if it isn't the real problem (having already spent >£500 with no solution!).

Has anybody had any similar problems and identified the cause/solution ????

Thanks very much in advance

Hi, I used to have a 1.9Dturbo Xantia, which showed similar symptoms to yours. On the M62, if I was >70mph, the temp would creep up dramatically to very hot, especially when going up the long hills. Soon as I went over the top and eased off - even if still >70, the coolant would come back down.

Turned out the radiator was rotten at the bottom and the bottom 5th was covered in leaves in various states of degradation.

It passed pressure tests no problem, but evntually failed big time.

I was adding water, but it wasn't too much to make me think rad, but enough to suggest head hasket.

Might be worth checking the front of the rad is unclkear and in good condition?

HTH,

Oh forgot to mention, new rad fixed it all LOL

[chalkmyster]

Good afternoon,

I have a 2002 1.9 tdi Sharan, having the same issues as other members on this forum.

Has any changed the water pump or other parts and solved this problem.

I have taken this car to a VW dealer, and I was surprised with there verdict......."nothing wrong with the car", not sure if this was because the car was still under warranty.

If any one has changed the water pump, is there any tips and a step by step process of what to do.

Kind regards,

Chalky

[Crasher]

Water pumps can suffer from failed or even completely detached plastic impellers than can cause these symptoms. The cam belt has to be done as well and it isn't a nice job on a Sharan.

[wattssharon9]

HI, have similar problem on 1999 sharan - overheats if car put under pressure - usually up hill. Had thermostat, radiator, temp sensor and water pump changed but no improvement. Almost seems there is an air lock and I have read that it sounds like an air bubble inside cooling system located in the heater core and that you need to evacuate and refill the system with fresh coolant. But this needs to be done correctly to remove all the air form the system. Does this sound plausable?

[Crasher]

It is also a common AJM symptom of head gasket failure but is yours a 110 or 115?

[wattssharon9]

115