2001 Boxster S Engine Noise
 

Hey everyone- New to the forum but after doing some research this seemed to be the most knowledgeable forum for the 986.

I just purchased a 01 Boxster S with 36,9xx miles on it. I bought this from an extended family member in S. Florida as a project- so I knew going into it that it has an issue.

It has a very loud, very distinct engine rattle/tap during the entire RPM band. I had the car shipped to RD Automotive in Albany, NY for their diagnosis and opinion. Listening to it today on the lift the noise seems to be coming from the Left (DS) cylinder head. The car idles and runs quite smoothly- if you can overlook the noise ha!

Has anyone heard a noise like this or similar? Any ideas as to what it might be coming from inside that little engine?

Here is a quick youtube clip I took of the car inside the shop.

2001 Boxster S engine noise 3.2l - YouTube

Crap, that sounds awful!

Look for loose sparkplugs or exhaust manifold bolts, maybe.

Probably a clogged lifter from not changing the oil often enough. You should change the oil & filter & inspect the filter for anything other than oil in it. Adding any sort of engine cleaner will make the problem worse.

Oh, welcome to the best 986 forum! :)

I'll take a guess - broken valve spring.

This......

A broken valve spring or collapsed lifter was what I thought to myself when I heard the noise and where it was coming from. Have any of you seen valve springs fail on such a low mileage, stock engine? A valve spring generally does not just fail without something causing it to fail. That "something" is what I am fearing ha!

Well I ended up bringing the car home and tearing into it myself. I first changed the oil and inspected the filter to see if there was any major ferrous metallic particles in the oil/filter and if it would change anything. It didn't. Oil looked fairly clean/debris free. Some very, very, very small shimmering specs in the filter, but nothing I would say was major.

I next removed all the coils, and spark plugs to inspect for any obvious cylinder issues, oil/fluid contamination, detonation, damage. All looked ok, and all look like they were the correct color. No oil contamination.

Then I removed the accessory belt to see if that would stop the noise- again no change with engine running/belt off.

So yesterday I took the transmission out (fairly easy job and +1 for the pelican parts guide). Took me about 2 hours to get it out on my back. Anyway- I inspected the (recently new) clutch and flywheel area for any loose/backed out bolts or damage signs back there- all looked ok.

Removed the IMS bearing cover and the bearing looks brand new.

Now I am stuck as to what my next step should be. I guess I should have mentioned that myself, and a good mechanic friend took a second listen with the engine running and the noise seems to be coming from the area on the drivers side chain tensioner, and IMS bearing area. Originally the noise sounded like it was farther out toward the head, but with a good mechanics stethoscope, and a screwdriver to feel for vibrations it definitely seems to be coming from that tensioner/IMS area.

Has anyone ever experienced a bad chain tensioner that would make a noise like that? Mind you this car was checked for cam deviation and that was spot on. I checked the timing marks and it still appears to be in perfect time.

I'd hate to scrap this engine with the thought of it still being something simple, but I guess maybe it's time to look into replacements/reconstruction?

Can the external tensioner (located on the rear of the even bank, near IMS bearing/flyhweel on the left side) be removed without locking the cams if the engine is not rotated?

I want to remove that tensioner to inspect for any obvious clues to the noise. Also it is leaking oil from that tensioner.

whoa nelly! I'm pretty sure you need to lock those shafts in place. I don't know enough about this but my valves got bent when a 'Porsche trained" indy mech. installed a new LN IMSB. These engines are complex and my 2001S has 5 chains in there!!!

When the engine is anywhere besides TDC there are valvesprings fully compressed. If the car sits for long periods of time (months) this can cause premature failure of the valvesprings.

I just posted on your thread in Pelican Parts with photo re: your next step.

You will need a new crush washer & O-ring to fix the leak.

See your post on Pelican forum.

Thanks! I will check it now

On a side note: How much free play is tolerable for the DM flywheel? When I was disassembling I noticed it probably had a 1/8-1/4" play left to right. Is this within spec for some movement? I know my measurment isn't exactly precise, but a rough guess.

How much should the chain tensioner (nearest the oil pump) be able to collapse? It barely moves 1/4" and becomes rock hard. Doesn't appear to be any cracks on the contact pad inside the engine case, and the wear pattern is central on the end of the tensioner.

Your flywheel is great, tolerance is about 1/2"

Is this the tensioner with the spring preload plunger? You should be able to compress it 1/2" - 3/4". To properly test it, place in hot clean engine oil 2" deep & pump the plunger. You should see dirty oil coming out making room for clean oil to go in.
Easiest to do this in a electric cooking pan @ 250 degrees.

Ok great. I pumped it in a container of clean, ambient oil for about 10 mins and it loosened up. I will do again with hot oil to make sure its all the way cleaned out.

I am afraid that the ~15k mi oil changes my uncle followed with this car sludged this engine. According to his service records it has had 3 oil changes in 36,975 miles over the course of 12 years HA!

I think some dirt and sludged oil may have partially or fully collapsed a lifter since everything else in the area seems to be in good working order.

Is it ok to run this engine with the trans out and the flywheel on? The engine is well supported, and I can easily put the exhaust on and support that without the trans in. I would like to listen for this noise again and be able to get closer.

**note I won't touch the flywheel ;)

I had the same question too! We need a voice of experience here. Who has done it, please step forward!

Well I ran it for over an hour tonight with the trans out. Had the flywheel on and torqued, all went well! Had a slight drip from slave cylinder...that was the only real issue with it running with the trans out

Yeah you can, you just have to compensate for the missing transmission mounts.

Cool beans!

Thanks for the 'post of experience'. The engine is supported in 2 spots with a large piece of HDPE. Only need to hear it for a few seconds to determine what path to take.

So, Wilson01S, are you fixed then? What did your engine tell you when you ran it? No more "clunking" I hope?

I too heard that by removing the OLD oil from the chain tensioner and replacing it with NEW oil, it may calm down the 'regular' chain startup rattle…yours was NOT a rattle - but the RATTLESNAKE SHAKE! :eek:

Bet you'll be doing REGULARLY SCHEDULED oil changes from now on!

This car was my "Uncles" and I believe he followed the 15,000 mile oil change interval....unfortunately the car has 36,984mi and its 12 years old!!!!!!!!!

I have always changed the oil twice a year on our 98 boxster base (it only gets ~2000mi/year) so I do a change in the spring and a change in the fall before its stored.

Anyway I pulled the cam cover yesterday...I will take the cams out today. Nothing looks abnormal yet with the clutch, IMS, compression, spark plugs, exhaust manifolds, and now under the cam cover.

ByProDriver- is there a spec or anything I can look at to see if I would have a failed lifter? I will have them all out this afternoon and I am just wondering if there is anything I can look for to see if one is bad?

Thanks again guys and I will keep you posted and upload a ton of pics over the weekend!

http://986forum.com/forums/uploads01...1370020231.jpg






Just like the tensioners. Cook at 270 degrees for about 8 hours in new oil, then pump up. Make sure to replace lifters on same valve if they pass the test. Is the tensioner in this pic the one you removed??

That looks just like the tensioner I inspected. What tensioner do I need to remove in order to take the cam gear and chain off the drivers side head?

Also what is the "test" for the lifters? I will submerge them in hot oil, but is there anything I should look for, or is there a certain amount of pressure they should be able to hold?

Ok I removed the cams and lifters and have the submerged in the oil bath now. My question is they are all hard as a rock zero play. Maybe they have to soak in hot oil longer? I would figure even in ambient temp oil they should have some movement?

I was hoping I would find one that looked bad, or acted different from all the others. Now I am back to the drawing board as to what this noise can be.

I never posted on this thread that when I ran the car with the transmission out (I ran it for about an hour with 20w50) the noise went COMPLETELY AWAY for about 4 mins. I recorded it for about 30 seconds. Then the noise gradually came back to where it started from.

This leads me to believe that it really has to be a lifter? What else could have stopped just from a fresh oil change and came back???

The 4-6 cyl. chain tensioner is on the top side of the head. In the picture below it's next to the cam position sensor. It's under the A/C compressor.
Let the lifters "cook" for a good 8 hours at about 250 degrees. Press down on the plunger to purge the old oil, you will see dirty oil squirt out, keep pumping until no more dirty comes out & the plunger gets too hard to compress again. You might need to add a quart of Marvel Mystery oil to the pot.


http://986forum.com/forums/uploads01...1370042574.jpg

Thanks again for your response. I found that tensioner and removed it, followed all the steps on the pelican parts tech article and got everything apart no problem. I let the lifters cook in oil about 220 deg for an hour and I could not plunge them at all...no pump action, no dirty oil. I will add marvel and cook longer?

Just removed the lifter guide tray to inspect valve springs....all look perfect.

I just noticed that the cam shaft/tensioner/chain assembly I removed from the 4-6 head does not have the color coded links lined up with the index dots on the gears. Did I remove the 4-6 cams with having 1-3 on TDC exhaust? Seems like I am a cycle out. Should I carefully spin the engine and guide the chain and gear that are just sitting for the 4-6 head until I reach TDC for the other side since that is not apart? Whats the safest way to retime this engine now that I have it apart, and what seems to be out of sequence?

There is a 50% chance you are 360 degrees off for setting 4-6cyl cam timing. To verify remove the 1-3cyl green cam plugs to visually verify 1-3cyl cams are timed right. If the 1-3 cams are correct for TDC then 4-6 bank is 360 degrees off & you need to turn engine 1 revolution CLOCKWISE back to TDC. 1-3cyl cam notches will now be upside down & 4-6 cams are ready for install & timing.

Ok great, Thanks again. Thats what I was thinking. I'm 99% sure 1-3 is TDC right now, and 4-6 are 360 out.

I am about to order the parts for the car- Lifters, sealant, IMSB, install kit, and timing tools. Before I do what else could I inspect and look at to check for failure? I am a little hesistant to spend the money on these parts if in fact I can't 100% verify anything failed.

I know the noise was a 1/2 speed noise telling me valvetrain
I know using a stethoscope, and 3 different sets of ears the noise was coming from the 4-6 cylinder head.
I know all the lifters looked and felt exactly the same when I had them submerged in oil.
I know all the valve springs look perfect
I know the compression is great in all 6 cylinders
I know all the spark plugs look good

I did notice the tensioner below the a/c compressor for cylinders 4-6 had definitely more play in it than the tensioner near the oil filter for the IMS chain. Is this normal? They are two differnet styles, but the one closest to the IMSB and oil filter I could barely move by hand. The tensioner for the cylinders 4-6 chain I could move from a standing 3 5/8" down to 3 1/8" using just the palm of my hand.

http://i1133.photobucket.com/albums/...on49/tens1.jpg

http://i1133.photobucket.com/albums/...on49/tens2.jpg

This is the tensioner below the A/C compressor.

Does that seem to be a bad wear pattern on the side? It is only worn on one side.

Due to the wear & inaccessible location of the tensioner, I would replace it.
Replace the VarioCam chain wear pads even if not showing any wear. The new updated parts are made of a superior material that is far more wear resistant & resonably priced too.
Seems the long oil change interval has allowed the lifters to become clogged.
Really look the vave springs over very well, checking for any broken springs.

OK great. Thanks for the advice- are the chain wear pads available from Pelican Parts? I inspected them all very closely, but I will recheck. Also would I be crazy to just replace the lifters from the drivers side head and not the passenger?

Pelican has them here:
Pelican Parts - Product Information: 996-105-253-00-M100

Nothing wrong with doing lifters on one side & test driving before proceeding.

Thanks Pro

Is there a safe way to turn this engine over without having the cylinder 4-6 cams installed? I can hold the chain and sprocket while someone turns the engine over for me, but I do not want to over pressurize cylinders since all 12 valves will be closed

OK the timing mark on the intake cam (on the rear of the engine) is pointing 90* out toward the cam cover. The marks on the intake and exhaust cam (flywheel side of cylinders 1-3) are perfectly parallel with the seam between the cam cover and the head.

So I will need to rotate the engine 1 full turn clockwise,and repin the crankshaft so that I can then install cylinders 4-6 (which I now have the cams out of) so that they are perfectly parallel with the seam between the head and the cam cover correct?

Once I set the cam to cam timing with the new tensioner pads, and aligning the dots to the color coded index links on the chain, reinstall the cams, install the cam timing tool, reinstall the cam cover, and torque the cam cover down how do I know how to line the chain sprocket that is just dangling back up? Does it just bolt up and because the cams are timed together, and timed with the other head it should just work? It appears that the sprocket has some adjustments so I want to make sure everything is timed not only between the two heads, but with the IMS

Sorry for the long winded question.

Also! Is there an updated tensioner for cyl 4-6 (below the a/c comp)? I ordered that tensioner and it is different than the one I took out. Seems to be about 2mm longer, and it has a large allen bolt instead of a hex head to tighten it with?