(Belt) Squeal at First Start Up of Day

Superblue has started doing this of late, and at first I assumed it was an old/loose belt (there are two, btw?). Her belts were replaced by NTB after doing something similar about 3 years/15K or so miles ago (which the tech told me turned out to be a PITA, btw :angry: ). I’m wondering if one of the belts might just need tightening or r/ring again :crossed_fingers:, although I wonder why that issue would come up at this point. Is that about par for the course with belts? I tried spraying belt dressing on them and that seemed to work at first, but only for 3 or 4 days or so. Last night I sprayed some more on them and the squeal/squall was still there on startup. :angry:

Before everyone jumps on the harmonic balancer bandwagon (which I don’t think is the issue), I would point out that USUALLY it only happens on first start of the day (or after the car has been sitting for many hours). The biggest clue though is that as soon as I heard the (secondary) air pump kick in, the sound disappears and everything appears normal. :joy: Or maybe the pump kicks in as soon as the squealing stops ? Again, does this sound like a loose belt or one in need of replacement? I’m wondering if the secondary pump has an electric clutch that needs to kick in, and, if so, maybe the clutch is wearing out ? When the belt(s) went out 3 years ago, it was similar, but eventually the squealing continued even while driving (even caught the attention of the local constabulary who pulled me over to give me a ticket for expired plates. :rage: )

Do the easy check and white out the HB just to be sure,

Can that be done from above, since I don’t have access to a lift? IIRC, it involves chalking a line across the flywheel + end of block and starting the car. After shutting off, the marks should still be aligned. Correct?

? Just mark the inner and outer rings of the Harmonic balancer run the car and if there’s a squeal stop the engine and check the lines.

Ribbed belts or V belts?

The 94 should have a ribbed Alt belt. Other belts are V belts.

OK, look at the pulley on the alt. Are the points between the grooves on the pulley really shiny?

Will check and get back here. What if they are, does that mean the pulley groove needs a good cleaning, or the pulley itself r/ring? :grimacing:

Late night I was a bit restless and decided to do some VERY light engine bay cleaning at the carwash, using a bottle of Purple Power (kinda like Simple Green) and “spot free rinse” water spray only. The particular bay I picked apparently the spot free rinse spray was REALLY weak - I mean I could have peed with more pressure. :blush: I didn’t actually spray anything directly on the belts (my target was mostly the top of the valve cover, which had accumulated engine oil on/in the “cooling grooves” on it over the past year or two from topping up the oil), but I’m sure some of the PP and/or water made its way to them. I thought when I started it for sure I would not hear good sounds from the belts (either the earlier squeal or something else), but surprisingly, it was perfectly silent. :open_mouth: Same for start ups a couple of times later on that night. This a.m. she only briefly squealed (and not as loudly) before stopping, too. So, I’m wondering now if maybe the pulley grooves and/or belts have grease/grime in/on them and that is the source of the squeal. I’m thinking of hitting them with some of that engine cleaner foam spray later today to check that possibility out, unless you guys advise otherwise. :confused:

I always understood that a belt squeal is the result of a belt and a pulley not moving together at the same time.

That just means you had lubricated it. Still slipping, just not squealing.

It means the pulley needs a workout with a flat file. Both the pulley and the belt wear, allowing the belt to ride deeper and deeper in the groove. With a V-belt, no problem, just tighten it up. With a ribbed belt, after a while the belt is riding on the points of those grooves in the pulley rather than wedging down into the grooves. The tops of those ridges between grooves being polished shiny is a dead giveaway. When that happens, tightening it up doesn’t help, it cannot develop any friction riding around on those points. It’ll slip and squeal until you do something about it.

The thing to do is use a flat file on that pulley, filing the tops off of those points. Doesn’t have to look pretty; you can actually do it by hand, it’ll work fine. File until you see some width on each rib on that pulley. It’s hard to file it too far; the farther you file it, the longer it’ll be until you have to do it again. Ideally, get the alt out of the car, use a drill with a socket to spin the alt while you hold a file against that pulley.

Normally don’t have to do anything other than the alt pulley. The crank pulleys are large enough that they’ll drive without slipping, and they don’t see as much wear.

Oh great … so it sounds like Jag moved from something that worked (v-belts) to something that doesn’t (ribbed belts) … :roll_eyes:

Wasn’t just Jaguar. I first diagnosed the problem on my 1985 Honda Accord.