Cary_West

I've developed an intermittent squeaking noise from the front left part of my engine head (around the #4 cylinder, I believe) after performing an IMS replacement on my 5 chain 3.2 motor. After IMS / Clutch, I replaced the gearbox and drove off for a couple miles, heard the noise and drove back, the car's been laid up since.

It only presents with load, and can be heard when blipping the throttle from idle, and also when accelerating or even just engaging the clutch against the brakes. It does not seem to be present when engine is at steady or falling RPM (except via slipping clutch method).

This video of the noise persisting was made by slipping the clutch a bit against the parking brake to load the engine a little:


Things I've tried that have not made noise go away:

removed exhaust except for manifold
removed serpentine belt (rules out water/PS pump/belt)
removed transmission (not clutch)
changed flywheel
removed oil fill cap (AOS not leaking vacuum)
changed out IMS bearing AGAIN
removed ignition fuse and turned over engine using starter w/ plugs in

None of these have made the noise go away. I am hitting the end of my rope. Please help.

Cary_West

I should mention, I had to do A LOT of banging on the IMS shaft itself with impact driver to remove a stuck-on installation tool nut.

Macster

Well, all I have are guesses and conjecture and none are I'm sorry to say pleasant.

But before going on...

I have to stress you need to try to pinpoint the source of the noise as best as you can.

Then I'll say right up front if you determine the noise is coming from say where a camshaft chain drive/tensioner is located that IMS banging might have done some damage internally.

If I'm right, and I hope I'm not, you might be faced with a possible engine removal and partial tear down to get at the area you have id'd as the source of the noise.

But before doing that...Have you dropped the oil filter housing and looked at the oil and inside the filter for say any signs (debris) of the composite plastic covering of a cam chain guide/tensioner?

The noise brings to mind various other possible explanations but you report doing what I would/could think of and if you have done these right you have eliminated the FW rubbing against say the crankshaft position sensor, a bad clutch release bearing, or a bad or improperly installed clutch, a dry (or damaged even missing pilot bearing check that a needle bush[ing] that fits inside the FW), an improperly installed transmission (misalignment mainly I'm referring to).

That the noise appears to be tied to teh clutch suggests sometihing in the clutch/transmission area is suspect. But this is why pinpointing where the noise is coming from, or at least not coming from, is so very important. Engine or drivetrain noise from one area can appear to be coming from another and unrelated area.

You have eliminated the noise coming from any accessory drive or serpentine belt idler/tensioner roller bearing.

A real far out suggestion would be to make sure there is nothing that is contacting the crankshaft pulley that is causing the noise. Now consider the crank can have some end play (not much, usually) but there may be more than is normal (I hope not) or there is something that got bent/pushed out of position that is contacting the crankshaft pulley.

Sincerely,

Macster.

Cary_West

It's not the clutch. It does the noise when stripped down to the flywheel. This appears to be the location. I think there's a tensioner paddle in there.

The oil filter is clean of debris.

Macster

That large round bore looks like where an oil scavage pump would fit. Which reminds me: These are no interchangeable. While they will physically interchange if interchanged they'll not work right.

Oh, be sure there's nothing in the oil scavage pump that could be causing that noise.

Just out of the pic to the left (towards the center of the engine) is a plug of some kind that I think is a chain tensioner.

(I'm working from some pics I took of a Boxster engine in a junk yard and like most pics the area of interest at the time I took the pic proves to be not the area of interest when I go back to use the pic for reference. In fact I have some pics of an S engine with a sick IMS bearing too and while I have a larger view (the entire front and back of the engine to name two views) what's actually behind that plug is beyond me.)

If I'm right all I can think of is that during the IMS repair this created/caused some chain slack to occur and this might have allowed a chain tensioner to slip out of its bore or the tensioner and the rail connection to separate.

It looks like removing that camshaft cover and removing the cams and possibly even the VarioCam solenoid/actuator to see what you can see might be called for. But that's a lot of work -- WAG based on having this work done on my Boxster is 9 hours labor in there and out again -- and there's a lot that can go wrong if you screw something up.

But where to go from here I'm not really qualified to advise you.

So, if I were you I wouldn't go any deeper based on what I have said.

You need to seek out someone who's been in these engines enough to know what's behind there and other places well enough to know if going in there or going in somewhere else is warranted.

Sincerely,

Macster.

2000

Did you figure out what this noise is? My car makes the EXACT same noise...

If I take it on the highway for a while, it goes away, then the car can be re started and driven with no noise. If it sits for a while, and cools off, it is back again.

Thanks!

Macster

When did the noise first appear? Was anything done to the car recently?

Based on what you wrote I'm going to have to offer either an exhaust leak or a loose spark plug.

2000

No work done recently, and it has been going on for about 6 months or so... I am going to put a set of plugs in it, and hope that fixes it. It does appear to drip a little oil on the passenger header, and the squeak sounds like it comes from the same side.

The video of the noise that Cary_West posted of his, is exact. It has to be the same issue.

Macster

AFAIK, we do not know what was the source of the noise in the case of the OP's car.

There was some speculation as to what it might be, or could be, but I have not seen a follow up from the OP.

He had worked on the car, changed the IMSB, and some other things so the noise could have come from something he did or didn't do. AFAIK he didn't check the plugs. He did remove and install the exhaust and the noise was unaffected so unless the exhaust leak was at the point where the header bolts to the head the odds are it is a plug noise.

Hard to believe in your car's case it is something chain tensioner or even IMS/IMSB related. I mean the noise has been around for 6 months…

Generally with an engine making noises from a bad tensioner or IMSB the car doesn't last 6 days, sometimes not even 6 minutes.

'course hard to believe a plug could remain just loose enough or an exhaust leak remain unchanged over that time to make the noise over 6 months of use too.

Have you dropped the oil filter housing and looked at the oil in the housing and the filter element?

Be sure if you do this you use a *clean* drain pan. You do not want trash from lawnmower oil changes to have you believing the Boxster engine is internally sick over nothing.

While I don't think you'll find anything scary it pays to be safe rather than sorry.

Have to say that with that noise I'd think it wouldn't be that hard to pinpoint the source of the noise with the car on a lift and you and tech under the car. Pinpointing where the noise is coming from goes a long way to helping you know what is causing the noise.

cvazquez

2000... Possible the lifter is failing intermittent noise is the same issue I've experience. The lifter may not be inflating. Place a long screwdriver to your ear and touch the area suspect will help support possible issues.

2000

And the winner is........

Spark Plugs!

A couple of them were not seated, and NONE of them were really tight.