Thats weird...usually Gates is pretty reliable wonder if it was a bad batch or something shipping with the wrong size bolt

 

I tried to get Rock Auto to see if the others were the same or even if the other brands had the correct size. Something they said they could not do..... (and were generally unwilling to help).

The bolt in the smooth pulley I received was the same size as the grooved pulleys, but in our car, it is larger (see pic below). The good news is that there is a collar in the bearing that can be removed making the hole the correct size for the factory bolt.

I am not the only one who has experienced this with the Gates part. Check out the review on

 

Damn, that sucks man glad you got it sorted though, sounds like a Gates problem taking for granted that the bolt is too small, they've probably been going by the outer diameter of the pulley alone...

seems like one of those things that if you contact them directly they might rectify it...if at least updating the compatibility list...

 

It also could be that this does fit an older G (G35 maybe) but not the newer ones.

Did send Gates an email last week describing the issue, have not heard anything back.

 

Hopefully you get it all sorted out. Is it recommended to change the idler pulley? I was just planning to change the belt but people say to change the tensioner as well. Did you replace the tensioner when you did your belt?

 

I replaced the belt, tensioner, and all 3 idler pulleys. Just did it as preventative maintenance as I plan to keep the car for a long time.

Depends on your mileage, tensioners tend to last approx. 100k miles, and bearings in the idlers do not last forever. With the belt off, you can see if there is movement in the pulleys. With them off, you can spin them in your hand. They should be smooth with no feeling of "grit". If they have movement while on the car or the bearings feel gritty when spun, I would replace. Good video to see what "movement" looks like:

 

Thanks for the info. I just hit 80k miles. I'll do a test like in the video to see if I need to replace the others.

Are there any good DIY g37 tensioner replacement videos?

Also which idler pulleys have the exact fit for our cars. Since you said the pulley you received from gates was the wrong size.

 

The tensioner (and idler pulleys) replacements are really easy. Once the belt is off, just remove the bolt that is holding it on and it will come right off.

The Gates Tensioner (39129) and the 2 Gates "grooved" idlers (36305) work great! The smooth one is the one I had an issue with (36306).

I am not confident that any aftermarket smooth pulley will have the correct bolt, and the Dayco may not even come with a bolt at all. I still used the Gates smooth pulley, just had to use the OEM washers, spacer and bolt.

 

Thanks for the part numbers I wonder how much the dealership charges for the smooth idler pulley

 

You can find the OEM smooth pulley (11925-EY00A) online for around $60

 

Youtube has some good videos on how to change the tensioner. It's pretty easy. It's an auto tensioner to you have move it by hand and stock a screw drive in it to lock it out of place to be able to slide the belts off and on. Just be mindful of the way the belt is routed when you put it back on by looking at the diagram in this thread or others

 

Sorry for bringing the thread back up. Before changing out my belt I noticed that the belt tensioner was almost out of range on my old belt. Would that change with a new belt or should I buy a new tensioner?


Shown on the top right. Mine is near the 3rd line and almost out of range. New tensioner or would the new belt change it?

 

It could be that the tensioner is fine, but the belt stretched a little. Really the only way to tell would be to go ahead and put the new belt on and see where the mark is. If it is still almost out of range, it will be time for a new tensioner.

I would put my money on it being the belt.

 

Sounds good thank you! I had to buy a new idler pulley, the pulley kept making a weird noise when moving like it had something loose inside. All other pulleys seemed fine. I ordered the belt tensioner as well just in case.

What are the torque specs for the idler pulleys?

 

41 ft lbs for the tensioner and 21 ft lbs for the idlers. I could not get a torque wrench on the tensioner bolt (and maybe the idlers as well) so I gauged by force it took to remove them.