- Location
- Southern Maryland
I've got this mild whistling noise that has been bugging the crap out of me so I got under the hood and looked around.
First I checked vacuum pressure with a gauge from Autozone at various places, and I am getting approx 14 hg inches at the reservoir on cold startup, which then builds to about 17 hg after a couple of seconds. The reservoir also whooshes if I disconnect it after the engine runs for a while, so vacuum seems to be solid. I did have a couple of weak connections (brake booster, a couple of others) but after cleaning and clamping some connections overall vacuum only improved by 1-2 hg. If I disconnected a line the engine accelerated (MAP sensor) and ran like crap so the whistling noise isn't coming from vacuum.
I did a seafoam treatment and watched for smoke, and got a LOT of it from around the intake manifold, but I could not see where it was coming from. I don't think the intake is leaking or else I would see vacuum problems.
My guess is that the exhaust manifold gasket or the manifold itself has gone bad, and that the leak is the source of my whistling. The car also kind of sounds like it has a bad muffler--it's got that ricer farty sound, but not a rumble like you would expect from a big hole in the exhaust.
The other possibility, I suppose, is that the head gasket is leaking, although I do not have enough of the classic symptoms to indicate that (coolant and oil levels stay pretty consistent, no overheating, etc).
This is a '91 with 336k miles on the engine BTW
Thanks
First I checked vacuum pressure with a gauge from Autozone at various places, and I am getting approx 14 hg inches at the reservoir on cold startup, which then builds to about 17 hg after a couple of seconds. The reservoir also whooshes if I disconnect it after the engine runs for a while, so vacuum seems to be solid. I did have a couple of weak connections (brake booster, a couple of others) but after cleaning and clamping some connections overall vacuum only improved by 1-2 hg. If I disconnected a line the engine accelerated (MAP sensor) and ran like crap so the whistling noise isn't coming from vacuum.
I did a seafoam treatment and watched for smoke, and got a LOT of it from around the intake manifold, but I could not see where it was coming from. I don't think the intake is leaking or else I would see vacuum problems.
My guess is that the exhaust manifold gasket or the manifold itself has gone bad, and that the leak is the source of my whistling. The car also kind of sounds like it has a bad muffler--it's got that ricer farty sound, but not a rumble like you would expect from a big hole in the exhaust.
The other possibility, I suppose, is that the head gasket is leaking, although I do not have enough of the classic symptoms to indicate that (coolant and oil levels stay pretty consistent, no overheating, etc).
This is a '91 with 336k miles on the engine BTW
Thanks
