A couple of weeks ago Matt and I changed the timing belt on my car. It wasn't due yet, but I have had a front main seal leak that makes everything quite messy for 50,000 miles or so. We changed the belt (which was saturated in oil and a bit loose because of it), cam seals, and of course the crank seal. When we put it back together it was making a noise similar to a bad idler pulley bearing. It just had a not-so-subtle whine to it. We figured it was the crank plate behind the crank sprocket, since we didn't have replacement parts for those handy and the plate got a little bent while trying to get it and the sprocket off of there. The noise had progressively gotten worse, so today I tore everything apart again.

There were some metal shavings from the crank plate rubbing on the sprocket, which again was thought to be the cause of the noise. I replaced the plate, the sprocket, the belt, and the tensioner (just in case it had something to do with the noise). After putting it back together I can say there is no change in the noise, it is still loud, and I have no idea what is causing it.

Obviously it has something to do with the timing belt (yes, I am sure it is not coming from any of the accessories). I am now completely out of ideas and pretty pissed that a day of crawling under the car and probably $100 between belts, tensioners, and misc. tools has resulted in no change.

Anyone else ever had this happen? What the hell is causing this noise?

 

you are POSITIVE it's not the water pump? grandpa's van made a noise like an idler..... and then i was driving along and heard a clunk and the water temp rocketed to H.

 

Yes, I am sure. I was running the car w/o any accessories and with the timing cover off just to make sure.

 

check to make sure its a round toothed belt not a square one i remeber thatll make it whine but as far as the crank plate i got no idea

 

no way in hell Matt93se would make or overlook a mistake like that. he's a freaking pro.

 

I'm thinking bad dizzy bearing....

 

heaven forbid... bad oil pump? I have a spare oil pump if you guys wanna try that... i'm sure matt's got feeler gauges and whatnot to check clearances on your current pump if you decide to see if that might be the problem.

 

Feeler gauges? I don't need 'em. I just wiggle things around and measure the clearances by how much the move in my hand.


I have a set somewhere... I think...

The noise is definitely coming from something attached to the timing belt. I ran it in my driveway with only the t belt and nothing else connected. I was 99.9% sure it was the plate behind the crank pulley, as I could see it rubbing against the oil pump for a short while, but I took it off and flattened the thing out and put it back together. the noise went away for a couple weeks and is back now. WTF? grrr

 

well you said there were shavings in the cover, right? perhaps some of those got somewhere it shouldnt have, and you are thinking it sounds the same, but is just similar...

or, something may have knocked the cover back in?

 

got the plates installed correctly? there are two of them!

 

i think i have a spare one of them plate things... if you wanna try it

 

My bet is - the BELT. Wouldnt be the first noisy one. If noise is unbearable, swap.

 

Could you see where the contact was being made?

 

are you saying that the timing belt can just sometimes be noisy for no reason and swapping the belt for a new one will likely solve the problem?

 

am i the only one who feels like this might be the reason for the noise?

 

No. But. Noisy for a reason ...

The steel and/or fiber mesh inside the belt can cause noise without any problems - likewise the round teeth on square sprockets are noisy and may run 50k without problems (tested fact by stealership service). Noisy belt may also be faulty from factory and later cause problems (One GM noisy belt was broken to bits at 10k; cant really know the reason. My guess is that if it was replaced because of the noise, then...).

In my experience every fifth (?) belt produces some whine; but then I do swap only few belts per year.

 

Here is a video clip so you all can actually hear the noise. It's dark out, so there's not much to see...you can here the noise just fine, tho...

http://s32.photobucket.com/albums/d3...t=PB304842.flv

 

That is most definitely rubber rubbing against something..

 

Crap! That means that either the crank seal or one of the cam seals isn't recessed far enough in!

Anyone have pics they've taken of a crank seal sitting in place? I would be that is the culprit.

 

how well-centered is the belt on all the sprockets?

 

The plate I replaced behind the crank sprocket and the piece that goes between the sprocket and the crank pulley is what centers the belt. The belt's natural tendency is to ride slightly over the edge of the crank and cam gears, as I witnessed. I centered the belt on all the gears and started the car w/o the timing cover on. The tendency to move over a bit is what I witnessed, but I know that the outer plate would prevent the belt from rubbing if the timing cover was in place.

It's got to be one of the seals rubbing (crank seal most likely)...there's nothing else to consider.

 

Agreed. Typical belt noise (if any) is 'periodical' at idle as same belt area 'hits' a roller, sync like lame man walkin with water in one boot... (Wrong type or too tight adj etc issues affecting whole system excluded)

 

Fixed it. It turns out it was caused by the tension being set too high. I'm not sure if that was the cause of the original noise (may or may not have been the same), but this afternoon I tore everything down, adjusted the tension (very slightly) and put everything back together in 3 hours.

Thanks to all who posted!

 

i see....

i thought the spring auto-set the tension? or did you wrench it around tighter? when I did matt's tbelt, i just used the allen wrench to hold it out of the way while sliding the belt on, then let go and tightened the locknut down as-is... after turning the crank over a few times. did you keep holding the allen key when you tightened it the first time?

 

I adjusted the tension several times trying to get the noises to go away. It would go away for a few minutes and come back. I hope it doesn't, but I *DID* adjust the tension a half dozen times before doing all that.


.... wait.... I just listened to the audio track... that's a different noise than what I was fixing at my place. Mine was more metallic scraping.. That's definitely just belt tension noise. It would have gone away with time as the belt stretched slightly, alleviating the tension.

 

hmm.. so you don't just let the spring set the tension by itself (like the way serpentine belt tensioners do)? that's what i did on matt's car....... did i screw up? or is that OK? his never made any noises so i know it wasn't over-tightened like maxitech's was.

 

Something the audio clip doesn't have on it is how it would hit a harmonic resonance at around 800rpm, so at idle it would be much more noticeable.

I did initially think the sound was a bit different, but then convinced myself it was my imagination. I guess they really were separate issues.

 

FSM - section EM page 13/14/15/16 ................. If mine is anything to go by, I certainly wouldn't leave it only with the tensioner spring's adjustment ability - imo you need to do it properly.

 

LVR I saw that section too - but how on earth do you apply 20 lbs of force to the belt from above, exactly. Is there even a tool made to do that? Then in addition - measure the deflection within mm accuracy?

 

Get a cheap little scale - the type where you can hang a weight on a hook and read the scale - turn it upside down, hook it onto the center of the top horizontal part of the belt and pull till you see 20lbs.

As for measuring - you need to figure that out yourself - its simple enough

 

oh... well i did tighten the lock nut... so the tensioner isn't relying on the spring. i just used the spring to set the tension. I just didn't pull on anything while tightening said locknut. I put the belt on, let go of the allen key, pulled the allen key out, then tightened the locknut.

 

IMO that is wrong then ............... The tensioner has an in-built spring that, while the locknut is loose, will tighten the belt to the point where the tensioner spring reached its maximum ability - that happens to be not nearly enough to set the belt properly. Tightening the locknut at this stage achieves nothing other than locking the belt tension to that springs' tightening ability. The locknut has no use wrt tensioning - it simply prevents your pre-set belt tension from changing because of unwanted tensioner rotation

 

I have done many timing belts on VGs and they all have required more tension than just the spring. EM-14 and 15 in the FSM show you the procedure, although I rarely pay much attention to the "70-80 degrees clockwise" rotation on the tensioner with the hex wrench. I just turn it until I feel it has the correct tension, tighten the bolt and test deflection. If the belt is too tight, you will hear a whining noise but as Matt said the belt will stretch over the first 500 miles or so which will often eliminate this noise.

Rechecking the timing belt tension after 1000 miles is highly recommended.

 

...the euro-spring load has always been enough That comes true as left cam is turned slightly CCW 'feeding all slack' for the roller - maybe the cold weather gives the spring more stamina?

Whatever is done, even confuzean coreography jazz by FSM, the end result is what counts: check the belt tighness as specified by FSM - 10kpm force on mid belt causes 12mm (or even half inch) travel downward.

If this check is ok, doesnt matter how that point was reached. What matters is if u recheck the tightness, also later near end of belt lifetime...

 

hmm ok. well, as much as i hate taking off the timing cover on-car i guess i have to bite the bullet this time, and make sure the belt tension is OK. I guess Harbor Freight will have a little scale like that? i'm doing a 3G maxima timing belt on thursday as well, and i want to make sure i get it right, because the car won't be as readily accessible to me as matt's car is...

 

Learn it. Go find a personal weight scales, take big screwdriver and push down until u get 20lb reading. Repeat until ... now then run to maxima and repeat the push on the belt as a pro

Accuracy is your thumb thickness. And as said, the spring is there just and only for the pretension purpose, no other function. If testing shows inadequate tension, then just to get there, help the spring while tightening the nut.

The belt jump over danger comes (typically on 5 yr old belt) when there is no tension at all, but slack.

 

No need to take the the cover OFF. Just take out the two upper screws, pry cover ajar and have long screwdriver ready to push down. I have checked my belt at least twice (now 5½ yrs old belt, no miles at all). No change observed...

Plus, if needed, I have a hole in the cover to loosen the roller tightener, and let the SPRING do its designated work...

 

wait... oh.. you mean just measure off a half-inch of the shaft of the screwdriver and push down with 20lb force... then if the screwdriver went further in than 1/2" than i knew the belt is too loose? but based on how i did it, i think i might have to tighten it anyways... and for me, that means removing the cover, because i don't have a hole in my lower plate and i dont want to make a blind guess at where it is and just start drilling holes in the cover.....

 

Let me state the obvious and incur the wrath of the community:

This is not a job to experiment with - you either do it right or you don't do it at all.

A loose belt will at best allow you to retention it if nothing has happened - at worst it will jump a tooth or more or even come right off requiring an engine replacement at this age.

A too tight belt will at best allow you to slack off on the tension if nothing happened and it was only noisy - at worst the belt itself can break or more likely the nose of the crank can be broken right off (see the huge number of threads on this topic here already) also requiring an engine replacement.

Don't F**k around with this - if you are lucky to have a motor still running with an improperly adjusted belt and didn't understand the manual the first time round, make damn sure you do it right the second time round by removing the covers and following the manual - the fact that you guys are asking all sorts of funky questions leads me to believe any other method is bound to end in misery as a result of inexperience.

 

This verify 'process' is separate from adjustment, fast and easy. Any time a belt car is purchased, this is the first checkup. A belt will last over 15 years - if its tight; however, 5yrs is the right time to swap.

The belt tightness cant be ballistic rocket science: see how many stealership noobies do it globally every day and still success rate is almost 100%. Just observe for no slack and your out of danger zone, ideal force is the 20lb (which can be self learned easily, no tools needed.) Slack means you can raise the belt with no effort like your own belt when its on the floor... Tight belt = trousers wont fall
Thumb turning the belt 90 degrees is also valid non scientific measure.

Overtightening is neither a danger: noise starts quite early, but you really need some forceful jacking to cause the belt to break or cause other damage. Still, listening to any extra noise from there, keeps stomach upset, so...