Serpentine belt pulley size

[TheForger]

Currently in the middle of doing some preventative maintenance. I have the radiator and fan bracket/clutch/blades/shroud all out. I just removed the tensioner assembly and I noticed that the OEM unit that I pulled off does not have the same size pulley as the Gates 38488 unit that I purchased as a replacement. I purchased this Gates assembly off Rock Auto and it said it would fit so I didn't even question it until now that I have them side-by-side. The OEM unit appears to have a 4" pulley, while the Gates replacement has a 3.5" pulley. What gives? Do I need to return this one and get the 4" pulley??

Tensioner assembly comparison; OEM on left, Gates 38488 on right

OEM tensioner with 4" pulley

Gates tensioner with 3.5" pulley

 

[TheForger]

Dang...I just went back on RockAuto and I see that there is another tensioner assembly Gates 38173 which does have a 4" pulley. I guess I need to return this one and wait on the new one come in?

 

[TexLexican]

Blessing in disguise. Return the gates and buy oem.

 

[Trunk Monkey]

Timing Belt for Dummies writeup

If you’re wrenching for money leave it in, if you DIY and have the time then remove. It certainly is a little easier to work in that space with out radiator in the way and it’s only another 15-20min of effort on the way out and back in. Also with removed you can throughly clean the fins and if...

forum.ih8mud.com

 

[TheForger]

Timing Belt for Dummies writeup

If you’re wrenching for money leave it in, if you DIY and have the time then remove. It certainly is a little easier to work in that space with out radiator in the way and it’s only another 15-20min of effort on the way out and back in. Also with removed you can throughly clean the fins and if...

forum.ih8mud.com

Based on that it's making me wonder if this 3.5" pulley will work for me

 

[Mike NXP]

The accessory belt tensioner pulley size, even on OEM changed over the years. The pulley got smaller on the new part number and I suspect the design of the tensioner changed to accommodate that. I'm a sucker for giving Toyota my VIN and going for OEM parts so I'm not sure about the rock auto option. I know there is a Toyota part diagram somewhere that shows the two sized pulleys but I can't seem to find it.

 

[Mike NXP]

This is what I was thinking of showing the different part numbers and pulleys for the tensioner but they don't say the size. I can measure mine if that helps? The tensioner should make up for the difference, maybe install it all back and see how the belt feels. Luckily you can still work towards buttoning everything up and swap that out later on without having to do much to get to it.

https://partsouq.com/en/catalog/genuine/unit?c=TOYOTA00&ssd=$*KwEVITAAfxIMaxB3EnYEPU1ZeX5gER4TEgAeLFwEVQIdBHsBUlIPBRwQXVlTSEc-C05ET0UCHRcNARgZCAUcAxERFhABUlIFSQQbAhYQFxdPQS0FW19WTkJhWFwZGAUcA3ZuaAMPXBkfBRwDanNjaXdORSYQFBMQFR4VEEdSQAVFQgIdBBYaT0RZFwQNAkpFAxlcJTZtFxEQawtmbS41J2YEDQJBT0UBREERAAAAAFeMFqY=$&vid=0&cid=1&uid=384535&q=JTEHT05J722028439

 

[Mike NXP]

I may have this backwards so sorry if this makes it worse but I think this is the new smaller pulley with the 0w030 part number. Maybe cross reference that with your gates

I think this is the original bigger pulley. with 0w010

 

[TheForger]

This is what I was thinking of showing the different part numbers and pulleys for the tensioner but they don't say the size. I can measure mine if that helps? The tensioner should make up for the difference, maybe install it all back and see how the belt feels. Luckily you can still work towards buttoning everything up and swap that out later on without having to do much to get to it.

View attachment 3263203


https://partsouq.com/en/catalog/genuine/unit?c=TOYOTA00&ssd=$*KwEVITAAfxIMaxB3EnYEPU1ZeX5gER4TEgAeLFwEVQIdBHsBUlIPBRwQXVlTSEc-C05ET0UCHRcNARgZCAUcAxERFhABUlIFSQQbAhYQFxdPQS0FW19WTkJhWFwZGAUcA3ZuaAMPXBkfBRwDanNjaXdORSYQFBMQFR4VEEdSQAVFQgIdBBYaT0RZFwQNAkpFAxlcJTZtFxEQawtmbS41J2YEDQJBT0UBREERAAAAAFeMFqY=$&vid=0&cid=1&uid=384535&q=JTEHT05J722028439

I may have this backwards so sorry if this makes it worse but I think this is the new smaller pulley with the 0w030 part number. Maybe cross reference that with your gatesView attachment 3263218

I think this is the original bigger pulley. with 0w010

View attachment 3263219

Appreciate the part number help! I guess I'm going to return my 3.5" pulley and purchase the appropriate 4" through my local dealer. Problem is I ordered it as a Serpentine Belt kit so it included a new belt, tensioner, & idler pulley, so I would have to return everything which would set me back a whole week having the truck down

 

[Mike NXP]

Yeah make sure the dealer can still get it. I recall pushing them hard for the bigger size but since I bought the new tensioner it didn't seem to be an option. Good luck

 

[TheForger]

Yeah make sure the dealer can still get it. I recall pushing them hard for the bigger size but since I bought the new tensioner it didn't seem to be an option. Good luck

So did you remove a 4” OEM and replace it with another 4”?

 

[Mike NXP]

So did you remove a 4” OEM and replace it with another 4”?

Sorry I don't have the specific measurements but could measure when I get home.

I removed a larger pulley and replaced the entire assembly which came with a smaller pulley. I questioned the Toyota parts guy a bunch because it was the same belt number which made no sense to me. I was told the new style tensioner takes up the slack of the smaller pulley and keeps the same belt number .

Once installed it seems to have solid tension and still plenty of throw in the tensioner so I haven't thought much of it since.

 

[TheForger]

Sorry I don't have the specific measurements but could measure when I get home.

I removed a larger pulley and replaced the entire assembly which came with a smaller pulley. I questioned the Toyota parts guy a bunch because it was the same belt number which made no sense to me. I was told the new style tensioner takes up the slack of the smaller pulley and keeps the same belt number .

Once installed it seems to have solid tension and still plenty of throw in the tensioner so I haven't thought much of it since.

YESSS THIS IS WHAT I WANTED! I’m thinking that even though the pulley size is different, I bet they changed the internals to still apply the proper amount of tension to the belt. If you’d like to measure later it’d be greatly appreciated

 

[Mike NXP]

YESSS THIS IS WHAT I WANTED! I’m thinking that even though the pulley size is different, I bet they changed the internals to still apply the proper amount of tension to the belt. If you’d like to measure later it’d be greatly appreciated

Yeah I went pretty crazy over this for a while as I tried to chase down a belt squeal that I was convinced was because the smaller pulley. It was fan bracket related but I spent some time wondering wtf .

I'll measure mine this weekend and double check part numbers.

 

[abuck99]

If you have the original belt tensioner, and you wanted to replace just the pulley- I would replace with same size pulley. The new superseded tensioner (16620-0W100) is constructed differently - smaller pulley and a little different tensioning mechanism body.

If the original tensioner is still functioning correctly, and the pulley is in good shape, you can press the bearing out and press in a new bearing. Then good to go.

 

[TheForger]

If you have the original belt tensioner, and you wanted to replace just the pulley- I would replace with same size pulley. The new superseded tensioner (16620-0W100) is constructed differently - smaller pulley and a little different tensioning mechanism body.

If the original tensioner is still functioning correctly, and the pulley is in good shape, you can press the bearing out and press in a new bearing. Then good to go.

Really appreciate the tip! I’m still contemplating my options. The truck is obviously out of commission right now and I’ll be going out of town for work next week, so I’m not sure if I will be open to waiting any longer. I thought I did quite a bit of research before diving into this project but obviously not enough

 

[GTV]

The accessory belt tensioner pulley size, even on OEM changed over the years. The pulley got smaller on the new part number and I suspect the design of the tensioner changed to accommodate that. I'm a sucker for giving Toyota my VIN and going for OEM parts so I'm not sure about the rock auto option. I know there is a Toyota part diagram somewhere that shows the two sized pulleys but I can't seem to find it.

Can confirm this is correct. Also the pulley is not interchangeable between the tensioners, I tried.

 

[landarcht]

I'll be picking up the parts tomorrow at a local Toyota dealer for my 2005 100 series. The part number they provided is 16603-0W010 (type A) based on the VIN I provided. I assume that's the correct size for me? The description name is "Accessory belt tensioner pulley", does that mean this part number has both tensioner and pulley as a set so just add the serpentine belt and good to go?

 

[TheForger]

I'll be picking up the parts tomorrow at a local Toyota dealer for my 2005 100 series. The part number they provided is 16603-0W010 (type A) based on the VIN I provided. I assume that's the correct size for me? The description name is "Accessory belt tensioner pulley", does that mean this part number has both tensioner and pulley as a set so just add the serpentine belt and good to go?

Yes, the drive belt tensioner and pulley are one complete assembly. As opposite to the timing belt which has a stand-alone tensioner.

 

[TheForger]

Decided to run with the smaller 3.5” pulley so I got it all buttoned up and she is purring! Much smoother and quieter idle minus the notorious header tick but that’s a problem for another day. Even though the new pulley is smaller I can confirm that both the new & old serpentine belts were identical in size (it came as a kit). Seems to have the exact same tension as the old pulley. All in here are the parts that were replaced:

- Radiator
- Upper & lower hoses w/clamps
- Fan clutch
- Fan bracket
- Idler puller
- Tensioner assembly
- Serpentine belt
- Thermostat & o-ring