Missing Idle pulley (1 Viewer)

[polloelastico]

I'm going to replace the notched belts that the PO put on as they are finally starting to wear, and it looks like they also removed the idle pulley (wasn't aware this was a thing). I'd like to add this back and I already ordered a new one for the AC from Wits End, but I'm not sure if it's the same part for both and I'm also not sure how it should attach, since I'm not seeing a bracket or anything. I've searched on this, but haven't found the specifics I'm looking for.

 

[richardlillard1]

I'm going to replace the notched belts that the PO put on as they are finally starting to wear, and it looks like they also removed the idle pulley (wasn't aware this was a thing). I'd like to add this back and I already ordered a new one for the AC from Wits End, but I'm not sure if it's the same part for both and I'm also not sure how it should attach, since I'm not seeing a bracket or anything. I've searched on this, but haven't found the specifics I'm looking for.

It bolts through the oil pump cover. We typically discard them and throw them away as they’re pretty useless. The part number is not the same as the AC idler.

 

[inkpot]

I'm going to replace the notched belts that the PO put on as they are finally starting to wear, and it looks like they also removed the idle pulley (wasn't aware this was a thing). I'd like to add this back and I already ordered a new one for the AC from Wits End, but I'm not sure if it's the same part for both and I'm also not sure how it should attach, since I'm not seeing a bracket or anything. I've searched on this, but haven't found the specifics I'm looking for.

We throw away most of the water pump idler pulleys. They serve no significant purpose that we can figure.

 

[polloelastico]

Interesting. I would have assumed the OEM belts would be too long without that pulley.

 

[OGBeno]

I’m not sure that telling a newbie on MUD that throwing away an engine component is a good idea.

If you are advocating this, I sure hope you have an engineering reason to do so.... “we can’t figure out a reason it’s there” is a terrible reason to tell someone to discard an engine component... especially a rotating assembly.

Anyway...

 

[bhsdriller]

OP do some searching, it's been discussed a lot.

Many run without with no problems including me. I'm probably going on 5 years without

 

[Grandlooser]

Not sure the burden of proof should be on why it shouldn't be there. I'd like to see someone tell us why it is there (or WAS in my case)

 

[-Spike-]

Not sure the burden of proof should be on why it shouldn't be there. I'd like to see someone tell us why it is there (or WAS in my case)

I guarantee you the Toyota engineers didn't put it there to look pretty. They obviously had reasons, which puts the 'burden of proof' on the person who seeks to justify leaving it off. Just because we don't know why doesn't mean there isn't a reason. For example, it might lessen the chance of a broken belt damaging the second belt. Or it might extend the life of the belts. Of course, belts might be different/better today, and the benefit of the pulley minimized.

FWIW I don't run the pulley. I view it as an experiment, one that I might regret, but one that has been and is being done by a significant number of people without any reported discernable ill effects so far.

 

[ppc]

Interesting. I would have assumed the OEM belts would be too long without that pulley.

With or without the pulley the belt lengths are the same. The belts when properly installed do not go around the pulley but next to it.

 

[polloelastico]

To confirm, this is what we are talking about and it seems to include the bolt? Part# 1660366010

 

[-Spike-]

To confirm, this is what we are talking about and it seems to include the bolt? Part# 1660366010

Yep. As mentioned, the belts barely touch the idler pulley. They go on the driver's side of the pulley. You can usually install the pulley without loosening the belts.

 

[Grandlooser]

Right, I feel like if this was 1993 and you removed it from a new one it would be somewhat questionable to experiment. However it seems we got a couple decades of experimentation under this particular belt with no bad reports attributable to it's deletion. Not sure how much more is needed.

In 25 years looking at engines, I never saw such a scheme, and it's not like all other setups are handicapped because of omitting that type of pulley. The 1fz belt routing isn't some alien tech.

Not to mention you typically shoot for more belt purchase over a pulley rather than less. Without the pulley the alt has to adjust away from the block and without the pulley the belt gets more traction than with. Is it much,or does it matter?.....

As icing on the cake, it's another thing to create friction and has rotating mass. It's not noticable without the pulley, but at the same time it's not as though our engines have gobs of efficiency to spare either lol. Also my parts truck has one that's seized, if allowed to continue running, sooner than later that engine has no cooling or charging ability in the middle of the woods or on your favorite interstate.

 

[lumbee1]

Removing the idler pulley causes the head gasket to blow. I have seen this happen in person.

 

[Grandlooser]

Damn. Disregard then.

 

[BILT4ME]

I ran my truck for 25K miles before I knew it was supposed to have one. Then I installed one and I have driven another 84K.

IDK if it made and difference other than calming my OCD. I figure if Mr T put it there, so will I.

 

[ProjectsNMotion]

I run the Sequoia alternator with the Photoman bracket and the overdrive pulley, and I'm pretty sure my accessory belts don't even touch the idler pulley anymore

Cheers