Serpentine Belt Replacement Interval? (1 Viewer)

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Apr 6, 2019
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Portland, ME
Oh, that's too bad. You know, Mainers have a reputation, perhaps undeserved, of being very stout hearty folks - maybe because it's cold, dark and raining 8 months out of the year. But let us know how it goes next summer.

I'm originally from Miami... :) Then 10 years in L.A....
But 8 months of dark cold rain? Think you got us confused with Seattle... The weather is not THAT bad here (Southern part, near the ocean). But for around 4 months it's pretty damned cold and plenty of snow. The price you pay for a glorious summer of 15 hour mostly sunny days 75º and 40% humidity.

This situation is frustrating because I thought I had got all the needed maintenance done during the summer and early fall to avoid just this situation. I'll take this on the next dry moderate day we get. Looks like Thursday will be OK.

If I'm going to go through the trouble of removing the serpentine belt, should it not be replaced? I don't have a record of it being done and I have most of the service history of this LC since day 1. Are there date codes on those belts? I have the factory info on how to check the belt.
 

flintknapper

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May 22, 2004
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Deep East Texas
I'm originally from Miami... :) Then 10 years in L.A....
But 8 months of dark cold rain? Think you got us confused with Seattle... The weather is not THAT bad here (Southern part, near the ocean). But for around 4 months it's pretty damned cold and plenty of snow. The price you pay for a glorious summer of 15 hour mostly sunny days 75º and 40% humidity.

This situation is frustrating because I thought I had got all the needed maintenance done during the summer and early fall to avoid just this situation. I'll take this on the next dry moderate day we get. Looks like Thursday will be OK.

If I'm going to go through the trouble of removing the serpentine belt, should it not be replaced? I don't have a record of it being done and I have most of the service history of this LC since day 1. Are there date codes on those belts? I have the factory info on how to check the belt.

Yes, good idea to just replace it. Inspect the one you take off also. IF it has no significant cracks or crazing and the 'ribs' are not glazed then keep it for an emergency spare.

Serpentine belts rarely break....but they can 'wear' along the ribs and if your tensioner is weak....this will cause accelerated wear and belt slippage. The most common cause of serpentine belt failure is a seized pulley which will shred a belt pretty quickly. That is why we want you to spin each pulley and feel and listen for anything abnormal.

IF you don't find anything out of sorts there, then do a quick 'belt-less' start and listen to see if still hear noises. It's possible to have noises come from the timing belt area (water pump, idler pulleys, tensioner pulley, fan bracket). By removing the serpentine belt you isolate all of those components and locating noises becomes easier.

As you know....there are a LOT of turning parts on the front of the engine and as you have discovered, using a stethoscope there is usually a waste of time. That tool is typically more useful for locating engine 'ticks and knocks'. Otherwise... mine never leaves my toolbox.
 
Joined
Apr 6, 2019
Messages
138
Location
Portland, ME
Finally got a chance to do a quick test. Didn't have time for complete belt removal but I loosened the tension and pull the belt off the pulleys one at a time and spun the pulleys. The engine was <120ºF coolant temp and the ambient was <40º.

None of the pulleys made any noise when manually spun. The tension and idler pulleys did not seem to freewheel excessively.

I put some naptha on the belt to help disperse any oil contamination. With the naptha the belt noise came back for a while until the naptha flashed off.

I sprayed belt dressing on the belt ribbed surface and pulleys as best I could do without taking anything apart. The system is completely quiet now.

The only conclusion that makes sense: Either the belt is old or the tensioner is old or both. I guess the cold and moisture makes the problem worse and then the belt slips until the moisture evaporates due to heat from the radiator. That would explain why it never makes noise when warm and always makes noise when it cold and humid.

I did not see any cracks in the belt. I can't see manufacturer's markings on it either. So no way to tell if it is factory and what the age is.

Is there a way to tell the old style tensioner from the new one?
 

flintknapper

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Joined
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Deep East Texas
Might be best to just replace the belt ( 90916-02585). Install it and you'll know right away whether that was your only issue or if you also need to replace the tensioner (much more involved).
 

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