4.0 Idler Pulley Replacement OEM vs Gates Reference

I believe there is two kits for that idler, one comes with a spacer to make the inner diameter the proper size. It should be able to be purchased separately I don’t have the part numbers on hand but I remember I had to exchange that pulley out for the one with the spacer on my work truck.

 

Is the conclusion of this thread that you cannot in fact use Gates Idler #1 - 36174 to replace JUST the tensioner Idler?

I see it listed in the diagram but crossed out in red.

Thanks

 

@JRYTacoma it fits but I crossed it out as an option on my thread because that pulley has an offset, and a double bearing/extra-wide design, that reduces bolt thread engagement. You can overcome that with a longer bolt but finding a longer reverse threaded bolt is gonna be pricey. Its so much easier just to replace the bearing or get the Chinese-made Febest pulley/bearing. I have it as a backup and looks to be decent QC. However, I will not rely on it when there are quality Japanese bearings available that are not cost prohibitive.

 

Thanks for the quick response! I take it you can't just re-use the OEM bolt with the Gates idler?

 

@JRYTacoma The

$42 Gates 36174 Idler Pulley

Gates 36174 pulley or the ine from the tensioner kit? Not 100% sure on the kit, but I don’t see why not. With the 36174 is where you can use the oem bolt but you lose thread engagement. Someone posted a pic on another thread. There where 3 or 4 threads that engaged. That bolt can stripped out in the long run.

 

@Bruce988jl Did you ever end up pressing new bearings and reusing the pulleys? I know you mentioned somewhere back in this thread you were going to do that so you always had a spare set on hand. Any issues pressing due to New England rust?

I checked all of mine last night. Bean meaning to do it since I hit 100k earlier this summer.. None were terrible though the No.1 was pretty stiff turning, and the PS pump idler had way more play than I expected when rocking it back and forth. Im tempted to just buy all new OEM and be done, but if I dont have to spend $260 + shipping then thats also very tempting.. My only concern is rust inside the pulleys like I said.

 

Does anyone recall the placement of the Gates reducer/washer on the two #2 idlers?

#1 idler was clearly assembled with the reducer in the back of the pulley (against the block). I did the first #2 under the assumption it was the same. But the second one came out of the box with the reducer in the front.

Ended up redoing them both with the reducer in the front. Stackup as shown hoping to move the pulley itself as far back as possible (still seems like it sits too far forward)

 

@SR-71A You have two large washers on oem pulley? I only have one, on the front. With the reducer, it don't matter how you place the large washer. Without the reducer, the washer goes on where the raised portion makes contact with the center of the bearing, otherwise the outside edge will make contact with the outside edge of the bearing, generating excessive heat due to friction.

 

Very odd, my oem idlers, the two identical ones had no bushing, replacement KOYO idlers were the same. The lower idler was the same, appeared to be a reduced size inner race on tne oem and KOYO replacement.

 

He said he got Gates bearing/pulley. They use 15mm ID bearings, requiring the use of a 15mm-10mm reducer.

 

Got it, sure seems like a Band Aid way to do it when matching replacements are available. Hopefully not jinxing my parts I just installed.

 

Yes all three of the OEM on mine seemed to have a large washer / dust shield thing front and back (a few were stuck to the bearing pretty good). Pictured are the two #2s I took off. You can see in one of the pics the washers are not perfectly flat, makes me think it serves as a 'dust shield' to some degree even though the OEM are bearings sealed.

Last pic is how I ended up installing the new. Reusing the OEM washers and adding the Gates reducer in front in hopes of pushing the pulley as far back as possible. Not sure if I need the washers, and not sure if it matters where the reducer goes.

Edit: not 100% certain if the #1 had two washers or not. Was rushing to get the job done so I didnt get good pics of that one

 

Does anyone have any experience or opinions with labworks parts for the idler pulleys? They are all over eBay and Amazon. I don’t want to cheap out but at the same time I don’t want to spend $150 on oem pulleys.

 

@p16 No experience with that vendor. Opinion: at their price points, they are stamping their name on made-in-China auto parts with an unproven quality control record. If you can’t replace just the bearings, you can count on vendors like Gates, Dayco, AC Delco, etc… for the pulkeys. The oem pulleys have replaceable bearings. You can get made-in-Japan bearings from vendors like rodavictoria, keyword: 6302RMX.

 

Thanks for the insight, I’ll be sure to check into the bearings as well.

This seems like a pretty good deal compared to everything else I’ve been seeing.

 

Thank OP for providing all this insight on replacing the idler pulleys. I was underneath my truck the other day testing my pulleys for play and slop and I noticed my A/C idler pulley had back and forth play and it spun freely with a slight noise to it. Is that normal or should I change out the pulley? Both #2 idlers need to be changed they have some play and noise when spinning them.

 

If youre doing the others the last one probably isnt far behind

 

Yeah planning on changing all idler pulleys, tensioner pulleys, and new belt at the same time.

Just to make sure since I’ll be replacing everything already the A/C idler pulley shouldn’t have and back and forth play or noise when spinning it right. My feeling is it shouldn’t but I just want to make sure before I buy a new parts

 

@TheBlueBeast15 Correct, there should be no fore/aft play in the bearing, nor side-to-side play. It should also spin smoothly, no graininess. Some resistance is ok, it is a sign of tight tolerances; it will loosen up in time.

While you are in there, check the bearings in these components - PS, alternator, AC, water pump. Note that PS may have some fore/aft play. Mine has always had 1-2mm play.

 

thanks for the insight. In order to replace the A/C bearing would I need to order a new A/C clutch? I’ve been trying to do research but couldn’t find much on here or any videos just changing the pulley bearings. Though they never really say y replacing the Clutch the pulley bearing is being replaced as well.

Alternator, water pump, and power steering pulleys seem to be in good shape still no above symptoms of a bad bearing yet.