New timing belt sounds like a supercharger

[q2418130103p]

I just changed the timing belt, auto-tensioner, auto tensioner pulley, and idler pulley after 11 years and only 10k miles. I didn't change the water pump this go around because of the small number of miles... maybe that was a mistake.

Anyway, after about 100 miles I started to notice a whining sound that I can only describe as the sound of a supercharger. Its not super loud, but it was noticeable enough. After a quick google search I found that lots of people describe this sound exactly as I did and most of those people find an over-tightened timing belt. I find this pretty unlikely since I checked the tensioner both with the grenade pin method and by measuring the extension of the auto-tensioner and comparing that to the book value. I removed both accessory belts, just in case it was one of those.

Tomorrow I'll remove the timing belt covers and make sure nothing is rubbing, and I'll check the auto-tensioner's extension. I'll probably run the engine with the covers off to see if I can find if its a specific pulley making the noise.

Does anyone have a suggestion what else it could be (besides the water pump....)?

[stealthee]

When I first read the title, the first thing I thought of was the belt being too tight. The other thought is the timing belt itself. Did you use a kevlar belt? If so then that is likely your noise.

If it were me I'd tear it back apart and replace the water pump too. Age is just as big (if not bigger) than mileage.

[q2418130103p]

That's interesting. To me the water-pump seems like the kind of thing that would have to run to decay (short of a seal rotting and leaking).

It's an OEM belt.

I'll take it apart today, if nothing obvious jumps out as being wrong then I guess I'll replace the water pump. Or maybe I'll just do it anyway... I dont know.

[2fnloud]

Antifreeze can do bad things. Too much at risk to not change it with the T-belt.

[q2418130103p]

I took it back apart yesterday. Nothing was obviously wrong.

The belt was a bit tight I guess, the plunger was extended 3.8mm almost exactly, which is the bottom of the range in the manual.

There was some rubbing damage to the outside of the lower timing belt cover which was clearly from the crank pulley, however I am rather certain that damage was already there.
Its also missing one of the metal spacers which could probably have allowed that kind of damage.
9763


Anyway, I ordered a pump and lower timing belt cover as a precaution. Hopefully it comes in before next weekend.

[q2418130103p]

I replaced the water pump and lower timing belt cover and all is well. Additionally though I installed the belt a hair looser than before.

When I first installed the belt I used the grenade pin method but I also took a measurement with calipers and compared it to the book value. I found that the only way the pin was easily insertable was if the auto-tensioner was too tight (as compared to the measured value).

This go around I installed it so that the pin was a bit more difficult to insert, but still insertable, while the caliper measurement was just a hair on the tighter side of the measurement range.