Boost Leak

Ever since my turbo blew a year ago my Mk5 Golf 2.0 TDI (BKD) has never been the same. It's flat as hell low down the revs but takes off like a stabbed rat as the revs rise. Every now and then, if I disturb the boost pipes they seem to seal nicely and the car will run lovely for a while before going back to being flat.

It's really frustrating as the car is nice to drive when it's on song. I can hear the boost leak and it's does sub 40mpg which I think is pretty low.

I've done a pressure test on the system and it held pressure fine which was strange. I've replaced the intercooler, i've replaced the original alloy pipe that goes under the crank pulley with a later style plastic one. I've also replaced all the o-rings on the pipe ends.

When ever I do something, it runs nice for a while and I think it's fixed it and then it goes back to being horrible to drive. I think the leak is coming from the pipe that goes into the intercooler on the hot side as it has oil residue around it and if I give it a wiggle it'll usually seal for a while.

The spring clips that retain the metal hose ends as well as the ears on the metal fittings themselves are known to wear and allow leaks. Take everything apart and do a thorough inspection. I replaced all of the seals and clips on our Passat and fixed the same problem that you describe.

Thanks for the reply, I've just ordered them. Hopefully it solves this issue once and for all.

I recently replaced the lower hose to the IC. It had popped off and I noticed the ears/barbs were worn. Same with the upper hose to the EGR.

are you getting any fault codes for underboost at same time as this is happening? obviously you either need new pipe or the 'ol self tapper cure'.personally im not a fan of putting screws in boost pipes,so unless you wanna get ur tiger-seal out it looks like new pipe is in order

I've had the under boost code once or twice, not that often. I've logged the boost requested and the actual boost on vagcom and it's not giving as much as it requires until it hits full boost, then it does.
If the clips don't sort it I'll try self tappers as I'm sick of the bloody thing.