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'87 740 wagon turbo failure[ALL/1998] posted by Jim McConville on
Sunday, 28 September 1997, at 10:53 a.m.
Suddenly, my turbo indicator does not go into the yellow and the car has become sluggish. I suspect the turbo is not functioning. Should I go to the dealer with the family jewels? Can I continue to drive the car or do I risk damage to the turbo? Is there any test I can do to tell if the turbo fan is rotating? Are there any oil treatments that might free-up the fan, should it be carboned up? Thanks for any advice.
Re: '87 740 wagon turbo failure[ALL/1998] posted by Abe Crombie on
Sunday, 28 September 1997, at 11:21 a.m.
Before you get too terribly worried, Have someone check your turbocharger wastegate linkage for being bound up. If it stuck in the open position you won't have much boostand there won't be any other symptoms, i.e. black smoke , blue smoke, loud whine, or poor driveability.
Usually it can be freed up by spraying WD-40 on the arm pivot and working it back and forth with it disconnected.
Re: '87 740 wagon turbo failure[ALL/1998] posted by Robert on
Sunday, 28 September 1997, at 9:42 p.m.
Jim,
Your turbo gauge is basically a vaccum/pressure gauge. With the engine off it rests at its mid point indicating 0 psi. With the engine running, anything to the left is vaccum or negative pressure, and to the right is positive pressure. Normally aspirated engines always opperate with vaccum. With a turbo, when the turbo is boosting you will have positive pressure. If your gauge does not move past the mid point your turbo is not working or the pressure is being dumped before it reaches the intake manifold. Check the waste gate as Abe mentioned. Also inspect visually and by feeling along all hoses and plumbing between the turbo and the throttle body. A hole in any of these hoses will let your boost escape before reaching the intake. There is a valve inline with these hoses that mounts to a bracket with 2 bolts. If these bolts are loose you will lose boost there also. If one of these conditions are present you would probably see black smoke from the exaust on hard accelleration. Your hands will be filthy when you finish your inspection. Its a nasty job but someone has to do it. You may not feel a hole but simpley a soft spot that lets the boost escape. If you find no problem here, you can check the turbo by removing the turbo inlet hose. See if the impeller spins freely. If not, gather your jewels. Axial movement in the impeller shaft is normal, but if the impeller has or does make contact with the turbo housing, you can kiss the turbo goodbye. If the turbo is bad, I know of no cure short of about $1500. If you are not changing your oil every 3000 - 4000 miles I would suggest you start doing so. Good luck.
Robert
Re: '87 740 wagon turbo failure[ALL/1998] posted by Ray Hartle on
Wednesday, 1 October 1997, at 10:39 p.m.
Jim,
I had a similar experience and my problem was loose bolts combined with a bad gasket on the wastegate valve housing that Robert mentioned in his response.
I found it by rooting around looking for a loose hose or something. A new gasket and some locktite compound put me back in business.
Good Luck