'91 N9TE Whistling

[billbranch]

Hello Again,

Seems I always post here with complaints or problems. 

Sunday I drove 65 miles, nothing fast, 70-75, wastegate is set low.

Arrived in destination town and heard whistle from engine. Thought it was alternator.

Has no effect on power, boost, smoothness of idle, running temp.

Sorry for poor audio, but in start and stop you can hear it.

It seems to be from firewall end.

2016-04-26 20.20.36.mp4

[N9TE]

That sure sounds like a friction sound.  Does  the pitch raise with the RPMS?

[billbranch]

Yes

[billbranch]

This is I am 100% sure a vacuum leak. I monkeyed around, finally started pulling lines off the intake, when I did the pitch of the whistle changed. I pulled the line off the brake servo and completely lost the whistle. So I am looking for the union, under the intake manifold. What should I expect? Is this accessible from under the car in my garage or only if on a lift?

 

[Bean]

If you've pulled the large vac line off the booster - did you plug it and the noise stopped?  If so it's your booster.  If you haven't tried that - just use your thumb to plug the pipe and see if you can recreate the noise with your thumb on that vac line.  If you can't - it's the booster itself or the elbow on the booster that's leaking.

If the whistle starts up with your thumb plugging the line I'd suspect the line itself.  Not going to be vary accessible from any direction, but it might be easier on a lift.

FWIW - your engine sounds really nice. 

Rabin 

[billbranch]

Thanks for the reply and about how nice the engine sounds, Unfortunately, it is not the booster. And, as you said, it is not accessible. It is either under the intake manifold or behind the engine under the insulation. Roger has a smoke machine. I believe that is going to be the neatest way to locate the leak with no disassembly or false, time-wasting steps. The other alternative is as you suggested directing a jet of propane toward the hoses/tubes and listening for RPM increase.

Bill

[Bean]

Did you get this sorted Bill?  I'm curious whay it is/was....

Rabin

[billbranch]

Hi, Bean,

And naturally this is gruesome and just the way things go with the N9TE, I had gone to another friend/mechanic to have the whistling diagnosed and repaired; he had looked and listened and I l had left the engine running for ten minutes while we were talking. When I hopped in, the STOP light was on and the needle was almost there. The cooling fan was and had been running.

I do not know if I did any damage, but I also am not going to spend $200 getting rid of a vacuum leak when there are bigger fish to fry.

Roger is completing remedial work on The Silver Bullet aka 505S V6 this week. I shall swap cars and we'll make diagnoses and proceed accordingly. 

I do know it is a vacuum leak under the intake manifold. I am only using the car for trips to the dump and to GF's house but coolant loss is very slight.

I am also going to evaluate The Silver Bullet. We have reverted to old configuration on brakes. We discovered that on full suspension travel the control arm hits the back of the rotor. It's that extra 8 mm or so. If the car runs as well as it should it might just be for sale. I have a little body work to fix where another motorist at speed hit a highway cone and sent it into the side of the front spoiler, and you know how paint on plastic looks after the plastic bends.

Thanks as always for your interest and commiseration.

Best regards,

 

[mark459]

About 15 years ago I had this problem with my 87 505 turbo turned out to be the intake manifold gasket, it had blown out between the head and manifold,

Mark

[Goce]

Changing the intake manifold seal seams easy, access is good and changing manifold gaskets on turbo engine unless it uses MLS gasket is an often task, i've done it on every car i've owned, if there is no gasket available buy some Klinger gasket material and cut your on, i've been making my ones last 6 years and never had one leak or fail, i buy the Klinger gasket material at a tractor supply store and is cheap. Couple of years back i bought a car apparently with a cracked engine blok, diagnosed by couple of mechanics, when a leased to it i could hear a vacuum leak, and seen rusty water marks, brought it home and it turned out to be just a intake manifold gasket 3$ for the material the car was like new, sold it back to the men i bought it from for duble the price, my advice is don't be afraid to dig for the problem and try fixing it your shelf.

[billbranch]

Whitey III my third white 505 wagon (with the whistle) is going to see the doctor next week, so I am not going to pull any shenanigans and try to diagnose any problems. I want to confirm one way or the other the status of the head gasket/head in the car because I am not going to sell it with any unknown conditions. I'll post pictures and the gory details of both Whitey III and The Silver Bullet (got the car back everything is OK except the sunroof fait caca). Thanks to all. I am getting too old and time is too short for the daily travails of the turbo which override the abject utility of the car. The Silver Bullet is a wonderful running '89 V6. I'll enumerate all the repairs with the pictures. Both will be for sale and I want to offer both here rather than let them fall into the hands of unbalanced interlopers who don't know and appreciate the cars.