How many are running without an idler pulley (1 Viewer)

[chansdaman]

After a recent belt change, the idler pulley (one right under the alternator) started making a loud whining noise. After I took the pulley out (replug the hole with the existing bolt), the sound is gone and the engine is nice and quiet.

I don't know why the that kind of sound was coming from the idler since the bearings seemed fine. The sound could have come from the ribbed gates belts.

Question...how many of you out there are running their vehicles without the pulley? Looking for long term data. I don't want to spend the $50 to get a new pulley just to have the loud whining sound return. The belts are new so I don't want to change them out to the OEM type either.

I know! Should have bought the OEM to begin with...

BLUF: How many are running their cruisers without the idler pulley and what are some issues running the engine without the pulley...thanks!

 

[duraman03]

My brother has been running without the idler for about 1500 miles now even though I bought him the toyota belts I told him would fix his noise.

 

[john_eckels]

Sounds like you ran cogged belts over the pulley. The pulley is supposed to touch the top of the belt.

 

[chansdaman]

duraman03: is your brother having issues without the idler belt?

 

[The Proton]

When I purchased mine with about 96k it did not have one. I only discovered that it was missing after about 10k miles.

I now have just under 130k, and no issues without the idler pully.

Somehow, even after all that with no problems, I feel this strange desire to buy one and install it, after all, it must have some reason to be there.

 

[NLXTACY]

Gonna hate to admit this but my idler was taken off when I got the new motor at 61k. Its been almost 200k miles without the idler and no issues whatsoever. Of course that will change once I finally install my SC.

 

[IanB]

I'm sure this would make more sense if I had a LC to look at, but how are you able to run (I'm assuming since nobody mentioned otherwise) the same belt without the idler pulley, without having too much slack in the belt?

 

[Tools R Us]

... The sound could have come from the ribbed gates belts. ...

Gates belts make noise on the 1FZ, but are otherwise good belts. I know of a couple who have run without idler long term, without issue. On mine just enjoyed the sound, they were the longest lasting belts that I have run so far.

Sounds like you ran cogged belts over the pulley. The pulley is supposed to touch the top of the belt.

The ribbed side of the belt runs on the pulley, this is what makes the noise.

 

[-Spike-]

I'm sure this would make more sense if I had a LC to look at, but how are you able to run (I'm assuming since nobody mentioned otherwise) the same belt without the idler pulley, without having too much slack in the belt?

The belt barely touches the idler pulley. I rarely question Toyota engineering, but this one has me wondering. OEM belts aren't a problem, but most aftermarket belts, ribbed or not, seem to make noise on that idler pulley.

 

[tirewater]

The idler pulley is to dampen/prevent belt oscillations along that length of belt. If the belts become too loose they could oscillate enough to either hit each other or come off the other pulleys. The oscillation may be hard to test because it can occur at different RPMs and different load conditions (i.e. on or off the pedal).

Anyway, I wouldn't advocate *not* using the idler pulley, but through forum experience it looks like you're ok not using one for a certain time. If I were to run w/o the pulley I'd make sure my belts were tightened properly.

 

[-Spike-]

The idler pulley is to dampen/prevent belt oscillations along that length of belt. If the belts become too loose they could oscillate enough to either hit each other or come off the other pulleys. The oscillation may be hard to test because it can occur at different RPMs and different load conditions (i.e. on or off the pedal).

Anyway, I wouldn't advocate *not* using the idler pulley, but through forum experience it looks like you're ok not using one for a certain time. If I were to run w/o the pulley I'd make sure my belts were tightened properly.

Yeah, the odd thing is the idler is not on the longest stretch of the belts IIRC.

 

[azTony]

If you upgrade to a Sequoia alternator the belts do not touch the idler pulley.

 

[IanB]

The belt barely touches the idler pulley. I rarely question Toyota engineering, but this one has me wondering. OEM belts aren't a problem, but most aftermarket belts, ribbed or not, seem to make noise on that idler pulley.

Thanks for the explanation.

 

[tirewater]

I don't know for sure, but i would guess the size of the pulleys in between the run determine whether or not a idler pulley be put there.

I wonder if the idler was put there as a result of testing, or simply because engineering thought there should be one there?

Yeah, the odd thing is the idler is not on the longest stretch of the belts IIRC.

 

[Tapage]

I buy a new one idler pulley and run it with gates belts .. I will probably pop it when swap for tundra alt ..

 

[outinthewoods]

I've been running Gates belts with no pulley for about 1K.

Bought a new pulley before I read the posts on here about the ribbed belts.

So now I have OEM belts and a new pulley, and zero ambition to change out the belts. I'll wait till i need new belts, since it sound like people are running for a long time without the pulley.

 

[chansdaman]

Thank you for the responses

Sounds like I will be running my engine as is without the pulley until the belts need changing...

Thanks again for the responses. You guys are great!

 

[MaddBaggins]

I haven't had the idler pulley in quite a while, at least a 1-1/2 yr. I made a spacer for the bolt and put it back in. When I left the bolt out, it was leaking a small amount of oil.

 

[BrotherRob]

Mine was missing when I got it, 70k ago.

 

[80t0ylc]

I think that the only real concern would be if the alternator had a heavy load on it from an electrical draw such as heavy winching or some other heavy electrical need. You might, then see some belt slippage and possible squealing along with reduced alternator output. It's cool that Mr. T's design is so forgiving for average use, though.