Whistling

[nozzleram]

I need some help with this one. My daughter has her 98 ZX2 away at school and she tells me that her car is whistling like a tea pot. She held her cell phone out to the engine compartment and while the engine was running a faint whistle was noticable. Its really tough to try and diagnose problems over the phone with a teenager! The part that really stands out is when the car is shut off (all belts and pulleys are stopped) the whistle continues for a few seconds and tapers off like lifting a tea kettle up off the heat. This really strikes me as either a pressure (PCV) or a vacuum issue.

Anybody have any thoughts?

[Markb873]

I agree with it being a vaccum leak. Does the car run normal? With a PVC pressure problem their should be some drive symptoms in addition. My '98 Zx2 has some vaccum hoses with some dry-rot. So I wouldn't question her car having rotted hoses. After all they do have some age on them, but don't rule out a vaccum leak in the PCV hoses either.

-Mark

[nozzleram]

The car runs perfectly normal. Good gas milage, acceleration, and no check engine light. If this is a vacuum leak the next time the car is home I should be able to spray carb cleaner in specific areas of the engine compartment and isolate the leak when the RPM's increase shouldn't I? This would at least narrow down where the leak is.

[Markb873]

Yep, that will do it.

[osurlosers]

Hopefully you've fixed this problem by now. But if not, I wanted to let you know what it probably was. On the driver side of the engine, resting just above/behind the crankcase, there is a small filter (about the size of a tomato juice can)...it's black. It's called the crankcase breather filter. These things get plugged up and cause the whistling. I have my tensioner pulley and serpentine belt changed, and was contemplating having the timing belt changed, when I found the solution online. It sounds like the noise is coming from the serpentine belt area, but it's not. Anyways, the crankcase breather filter was between $15 and $20 after taxes, and it is very easy to replace. If you have a hard time finding it, just follow the small plastic hose from the air filter housing assembly up towards the crankcase...goes right into the filter. If you want to make sure that's what the problem is, wait for the sound to occur...leave the car running and unscrew the oil cap. If the noise stops, it was the breather filter. Easy as 1-2-3! That stupid noise drove me insane for a year before I figured it out.

[Midwestzx2]

Originally Posted by nozzleram

The car runs perfectly normal. Good gas milage, acceleration, and no check engine light. If this is a vacuum leak the next time the car is home I should be able to spray carb cleaner in specific areas of the engine compartment and isolate the leak when the RPM's increase shouldn't I? This would at least narrow down where the leak is.

DO NOT spray carb cleaner in there.. it can really mess with the MAF's readings. Sensors are well.. sensative to that stuff. If you do .. use sensor safe spray.

[nozzleram]

Thanks everyone for the advice. I don't get to this site as often as I should. I got the car home recently and finally had a chance to look into the problem. It was a PCV valve, $2.80 fix and about 12 seconds time. While I'm at it and befor I send it back to her I'll replace the crankcase filter as well.