Limp mode @60mph !

[Passat2003]

Hi After replacing the oil cooler, oil and filter change, flushing the cooling sys, new radiator, new water pump, new thermostat, due to oil contaminating the water via a breech in the oil cooler .....
I now have a power loss problem.

Everything is fine until at around 60 mph there seems to be a sudden drop in power and although the car will accelerate its very slow to do so. This seems to happen when the car is going uphill (motorway slip road) and I'm assuming this is "Limp mode"
The problem didnt exist before the "oil in water" so I naturally associate it with that event .

The oil contamination in the water was quite heavy. Could the oil have contaminated any sensors within the cooling system that would cause the symptoms?. I know theres obviously a water temp sensor -but what is the sensor connected to the bottom hose and do you think that may have been damaged by the oil.?

My only other suspect is the small plascticky looking valve underneath and slightly to the left of the water bottle, This has very small pipes going to it and whilst staring blankley at the engine in the hope it would miraculously mend itself, I heard a slight hissing noise like air escaping coming from this area. Is it just air passing through the valve? or should I suspect a leak in the pipework, Incidentally does anyone know what this valve is called and what it actually does !

So to sum up :
Limp mode at 60mph when engine under load.

Oil has been in water from faulty oil cooler.

Hissing from area of the valve under water bottle - sounds bleedin obvious but just like to make sure before I pour any more of my life savings into the engine bay.

I should add that the power loss is very sudden almost like a switch being flicked.

I'd also like to say thanks in advance for the help and buy you a xmas drink for your time and effort .

[Passat2003]

My only other suspect is the small plascticky looking valve underneath and slightly to the left of the water bottle, This has very small pipes going to it and whilst staring blankley at the engine in the hope it would miraculously mend itself, I heard a slight hissing noise like air escaping coming from this area. Is it just air passing through the valve? or should I suspect a leak in the pipework, Incidentally does anyone know what this valve is called and what it actually does

Anyone?????

[trungdong]

I'm not sure this is your problem, but something you can check anyway.

Usedcarexpert guide for Passat recommend to test drive a car on main road to check if it runs out of power at 70mph or when accelerating. "If the car runs out of power at 70 mph or has poor acceleration, then the air mass meter usually needs replacing. This is more common on diesels than petrol engines. The fault can be intermittent"

Good luck.

[Crasher]

Have you carried out a fault code read?

[Passat2003]

I'm not sure this is your problem, but something you can check anyway.

Usedcarexpert guide for Passat recommend to test drive a car on main road to check if it runs out of power at 70mph or when accelerating. "If the car runs out of power at 70 mph or has poor acceleration, then the air mass meter usually needs replacing. This is more common on diesels than petrol engines. The fault can be intermittent"

Good luck.

Code was 17964, Charge pressure control negative pressure deviation.

I've finally traced it and it was related to that small plastic valve( is it called N75 or something)

New vacuume pipe ...99p

sticking plasters for skinned knuckles £1.49

finding a small hole worn by abrasion in one of the 3 thin hard plastic pipes that run to the valve ..........priceless.

Cut off the offending 2 inch length of pipe and replaced with flexible 3 mm hose. Running like new now thanks.