Hi,
I wonder whether anyone can help me with what I think is a turbo problem on a 1.6 water cooled transporter 1991. New turbo fitted about 5 yrs. ago.
Now when giving the engine a bit of wellie for getting up steep hills, there is quite a loud intermittent hissing noise for about 4 seconds followed by a drop in power for a few seconds. This repeats until I lift off.
I have also noticed to the side and below the air filter there is a black plastic sort of breather about 50 mm in diameter coming off a black rubber pipe ( about 30mm in dia.). I has a short pipe coming off the side which looks like a rubber pipe should be attached. But there is no loose pipe in the area or any other place for a pipe to be attached. This is nothing to do with what I think is a similar breather which is securely connected to the cylinder head.
Thanks for the reply.
Presumably with the cork idea, it will pop out if the blow off valve needs to blow. Will try this low tech. idea.
Any ideas on the question of the surging problem?
Thanks again,
J
Thanks for the reply,
The surging problem I described was the intermittent loss of power and loud hissing noise when the engine is being pushed. I had no idea this may be related to the blow off valve. This was a separate question.
Are you saying that If the blow off valve is blocked off with a cork the intermittent surging / hissing will be solved? If so, what on earth is VW playing at putting this thing in in the first place?
Still, this must be the cheapest fix yet. When my broken leg allows me to drive again I'll try the cork.
Simple solutions are always the best.
Thanks again
J
Yes the cork may pop out and its was not easy on mine to get to so I passed a zip tie around the cork and manifold and pulled it tight. It seems to be fine.
The blow off valve is a safety device that ensures that the inlet system does not provide to much boosted air to the engine. The primary boost control is by the turbo wastegate that works by quietly releasing exhaust energy when the desired inlet manifold boost pressure is obtained. As above, the BOV gets weak and leaks (the hissing noise), when it does the inlet system vents boosted air and the engine looses power until the valve closes again. The long term reason for not letting this continue leaking is the turbo could over-rev as it has lost its workload and you loose power.
Hope your leg gets better before the sunshine ends...
Mal.
1990 1.6TD Atlantic
1 Wife, 2 Kids, not enough time...
Yes the cork may pop out and its was not easy on mine to get to so I passed a zip tie around the cork and manifold and pulled it tight. It seems to be fine.
The blow off valve is a safety device that ensures that the inlet system does not provide to much boosted air to the engine. The primary boost control is by the turbo wastegate that works by quietly releasing exhaust energy when the desired inlet manifold boost pressure is obtained. As above, the BOV gets weak and leaks (the hissing noise), when it does the inlet system vents boosted air and the engine looses power until the valve closes again. The long term reason for not letting this continue leaking is the turbo could over-rev as it has lost its workload and you loose power.
Hope your leg gets better before the sunshine ends...
Mal.
Thanks,
I feel a lot better now particularly having forked out an arm and a leg for a new turbo to be fitted about 4 years ago. The unit looks cheap enough to fit another rather than try the cork idea.
Hi,
Now that forum members have kindly suggested the intermittent hissing and loss of power is likely to be the BOV (blow off valve), does anyone know where I can buy one for a 91 transporter? GSF didnt know what I was talking about! Looks like a sealed throw away unit to me.
Thanks again.
Jonathan
