Induction Air Leak

1000 PR · Post by **1000 PR** » Tue Jan 11, 2005 10:52 pm

According to my local garage, my MK1 has a massive air leak in the induction system which is making the enigine run badly and proving difficult to tune, as a result of which it only just passed the MOT. Where could the leak be?

Post by **Lauren** » Tue Jan 11, 2005 11:07 pm

1000 PR wrote:According to my local garage, my MK1 has a massive air leak in the induction system which is making the enigine run badly and proving difficult to tune, as a result of which it only just passed the MOT. Where could the leak be?

If this is the case the air leak where it would matter and affect running would be between the throttle body and the head. Look for vacuum pipes that aren't connected or missing. Things like the inlet manifold being loose could also be a problem, but this is unlikely tbh.

Neil Clark · Post by **Neil Clark** » Wed Jan 12, 2005 12:35 am

If you spray WD40 around induction side and listen the sound of the engine will change when you find the leak as it seals it for a short time, wont do damage to engine

Neil

LimeyMk1 · Post by **LimeyMk1** » Wed Jan 12, 2005 9:44 am

There aren't that many vacuum hoses on the Mk1, I'd be inclined to buy a couple of metres of hose and replace the lot! They've got to be getting on a bit anyway, do them one at a time and it's a doddle!

crazylegs · Post by **crazylegs** » Wed Jan 12, 2005 9:00 pm

check the metal pipes that go over the top of the tvis as well.i had a tiny corrosion hole in one of these in a previous mk1.it took bloody ages to find.the car was running like a diesel.
just a quick question,if the garage say its drawing air they must have known where from so why did they not fix it or tell you what the problem was? a massive air leak cant be that hard to spot.does the car run ok or is it a bit of a dog at the moment?

1000 PR · Post by **1000 PR** » Wed Jan 12, 2005 9:49 pm

The car was behaving like a pig on the way back from the MOT but having left the car for a week or so, it is now running ok except for surging when on idle between 1000 and 2000 rpm or so, which could be the cylinder head gasket? I'll check the hoses for the induction air leak and try the WD40 trick at the weekend, thanks.

Post by **Lauren** » Thu Jan 13, 2005 7:47 am

1000 PR wrote:The car was behaving like a pig on the way back from the MOT but having left the car for a week or so, it is now running ok except for surging when on idle between 1000 and 2000 rpm or so, which could be the cylinder head gasket? I'll check the hoses for the induction air leak and try the WD40 trick at the weekend, thanks.

If the car is going up and down idling when it is cold then you likely have air in the cooling system. So no it is not or anything to do with the head gasket. Try bleeding the system.

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