Thread: TD6 Turbo Replacement

Originally Posted by bacicat

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Have you checked the vacuum line to the turbo modulator on the drivers side and the vac line from there to the turbo? If you loose vacuum to that, then you have no way of making any real boost. You'll get a sluggish engine and whistling when it tries to come on boost.

Arh no. Looks like some reading to get an understanding of what I'm looking for and how it works.

With no vacuum applied to a VNT turbo, the exhaust gasses are angled away from the blades of the turbine. If you work the engine hard in this state, it doesn't spin the turbine up and the exhaust gasses pass accross the blades at the wrong angle and out the exhaust pipe. This causes the turbo to whistle rather than produce any boost. The little turbo modulator has a small vacuum reservoir to ensure it has vacuum when needed. A simple check is to pull the vac line off the front of it - the line that runs to the front of the car and accross to the vacuum manifold - while the engine is idling. You should be able to feel the vacuum on the line easily with your finger. If its not sucking, you've found your problem. If it is, check the line down to the turbo - at idle, this won't have any vacuum on it. Easiest check is to pull it off and suck on one end of it with your finger on the other end.

Mine were badly perished and I had the same issue a year ago - just after I changed the intercooler, I lost power and had a bad whistle when trying to make boost. $10 worth of vacuum line later and it was as good as new.

Another issue could be a blown X ring on the intercooler connections, or a split in the intercooler - I've done all that too.. :0

All the best.

Woohoo I have boost!! And a quiet turbo again. Good advice above.

Not really sure where the leak was. I replaced 2 vacuum hoses - reservoir to control valve and control valve to turbo. Both looked very ordinary. I assume the inlet manifold has to come off to get to the vac manifold and the valve for the EGR. This correct to get to the other vac lines?

But the interesting thing was the inlet port on the vacuum reservoir twisted clean off when I twisted the hose – it broke off with zero force. So a repair with a tapered fitting shaped down and some epoxy resin last night – it may have been the culprit.

That was a cheap turbo job ! Harlie, I once had similar problems but it turned out to be loose exhaust manifold bolts. A great relief also ! I wasn't looking forward to pricing a new turbo either.
You can now enjoy driving again this weekend.

Laurie