My '95 Integra LS makes (just noticed today) a strange noise when I shut off the engine.

It sounds like a squawk that last for ~1sec right after I turnoff the ignition. I started the car again, opened the hood and reached in through the window to shut off ignition again. This time I hear the squawk followed by a hissing noise that lasts ~2sec. Everything else seems to be running OK.

I don't know to describe the squawking...I'd imaging a slipping belt type of noise but not high pitched.

p.s.
I don't have A/C or ABS, if that matters.

Thanks

 

Have someone else turn off the car so you can stick your head under the hood & locate the sound more closely.

Just a dumb guess... vacuum leak at the brake booster? Or a busted check valve that's supposed to hold vacuum in the booster.

 

I had a co-worker start and stop the engine while I listened to for the noise. It appears to be loudest near the intake manifold/fuel injectors.

The squeak/squawk is louder if the engine is warm. In addition to the squeak, I also hear "sizzling" (kind of like water on a hot pan) type of sound near the injectors as well as the hissing sound of something de-pressurizing.

Any ideas?

 

does it take more than a split second for your car to actually shut off? when u pull the key out, does the engine sound like it shuts off immediately? if ur engine doesnt shut off immediately, your car could be doing something called "dieseling", which isnt good in any case. dieseling is a condition in which gasoline continues to fire after the ignition has been shut off. In late-model engines, dieseling , or run-on, is caused by heat and the unusually high manifold pressure that result from retarding the spark at idle. In fuel-injected cars when the engine is turned off, fuel is automatically shut off, eliminating dieseling. dieseling can effect your engine's performance, as well as the life of your engine. make sure that itz not doing that, or else you may need some engine work.

 

The engine shuts off immediately after I shut off the ignition. listened to it a few more times and the squeak/squawk sound seems to be under the intake manifold. It sounds a little like when you let a little air leak out of a balloon.

Any chance there is a vacuum hose under the manifold that is leaking?

What gets de-pressurized when I shut off the engine? Sure sounds like something is de-pressurizing (hiss after the squeak).

 

The PCV valve & hose is located underneath the manifold. There is a oil-trap 'box' attached to the back of the engine block. On top of that is a little plastic elbow fitting - that's the PCV valve - it looks like a hose barb. From there the hose goes to the intake manifold. If that's disconnected it would be a big vacuum leak.

You might get a better look at things if you removed the big air intake pipe coming from your air cleaner.

 

After checking further into it the noise can be made to be contiuous if I let the car idle long enough. It does sound like belt noise and after checking my records, the belts are a few years old.

Picked up some new belts and during the replacement process I noticed that, with both belts off, when I rotate the front wheel (jacked up one corner and put it into 5th gear) to turn the crank shaft, I can hear a squeaking noise coming from somewhere behind the crank pulleys and maybe higher up towards the cam shafts.

Could the timing belt be squeaking? Anyone come across a squeaky timing belt before?

I replaced the belts but was not expecting much at this point. Sure enough, after a test drive, the squeak at engine shut off is still there.

 

i get a ticking out of my car it goes tick tick tick tick every few seconds when the engine is off is that normal?

 

Probably not the belt itself... Well, maybe you could check timing belt tension? Your description didn't really sound like a loose belt slapping around.

You had the external belts off... How were your alternator bearings? Is it possible that's what the noise was?

Inside the timing cover, about mid-height, is the tensioner pulley & the water pump. Either one can be making noise if its bearings are going bad. How many miles on that stuff? If you get in there at all, you'd be silly NOT to replace the timing belt.

 

The alternator (and P/S pump) spins freely when I took the belts off.

The squeaking noise is a rubber-on-metal type of sound. Crankshaft seal?

The car has ~100k miles and the timing belt was replaced ~34k miles ago (Dec '98). I'll be needing to replace my cam plug so maybe I'll take a look at the belt with the valve cover off. Replacing the timing belt might be a little beyond my "threshold" right now. Up till now, only thing that I have worked on in the car were oil changesh: I do have everything except for the strap wrench...

Thanks for replying.

Sunny