My 93 Explorer apparently has no idler pulley? | Ford Explorer Forums - Serious Explorations

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My 93 Explorer apparently has no idler pulley?

Dubious_Downfall

Active Member
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Messages
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City, State
Fife, WA
Year, Model & Trim Level
1992 Mazda Navajo LX
I was replacing the fan clutch on my Explorer and decided to go ahead and replace the serpentine belt. After I got everything out, I realized that the idler pulley, which is on my serpentine belt diagram under the hood, is non-existent. I'm not immediately worried, since I've been driving around without it like this for a while. But, if Ford put one there in the factory, it was probably for good reason.

So, my questions would be: Is it possible that my truck didn't come with a stock idler pulley? Do I need to install one? What problems can not having an idler pulley cause? If I do need one, what is the size of the mounting bolt, and what else is required to mount the pulley?

I apologise if this has been answered before. I couldn't find anything specific to the first gen explorer. If there is information already, I would really appreciate being pointed in the right direction. Thank you, everyone!
 



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I have never heard of one not being there. The reason for it is to cause the belt to wrap more around the alternator and power steering pulleys, increasing the wrap-around decreases the chance of slippage. I don't recall exactly how that mounts, so maybe someone else remembers the bolt.
 






I have never heard of one not being there. The reason for it is to cause the belt to wrap more around the alternator and power steering pulleys, increasing the wrap-around decreases the chance of slippage. I don't recall exactly how that mounts, so maybe someone else remembers the bolt.

A big thank you for the quick reply, Roadrunner.

So, essentially, it is there to keep tension on the belt in a spot where there would otherwise be slack due to the distance between the pulleys. If I'm interpreting that correctly.

In that case, I will start putting together the set of parts I need to install a new one. A pulley is really easy to find. The hardware isn't. So, any help in that area would be greatly appreciated.
 






A big thank you for the quick reply, Roadrunner.

So, essentially, it is there to keep tension on the belt in a spot where there would otherwise be slack due to the distance between the pulleys. If I'm interpreting that correctly.

In that case, I will start putting together the set of parts I need to install a new one. A pulley is really easy to find. The hardware isn't. So, any help in that area would be greatly appreciated.

Tension is set by the tensioner pulley. The idler pulley pulls the belt down, making it wrap more completely around the alternator and AC pulleys. If a belt wraps 1/3 of the way around a pulley, it will be more likely to slip, compared to a belt wrapped 1/2 way around. It's a friction thing.

If memory serves, you just need a bolt the right length, and a flatwasher on the front side of the pulley. There should be a boss there with a threaded hole.
 






Do you see the hole for the idler pulley bolt?
 






How would you get a belt on/off without a idler/tensioner pulley installed? All the accessories on a serpentine belt system are hard-mounted (no adjustment like older setups).
 






The idler pulley is at the top of the engine, over the water pump. It is fixed. There is also a tensioner pulley, below the alternator, which is sprung to apply tension.
 






The idler pulley is at the top of the engine, over the water pump. It is fixed. There is also a tensioner pulley, below the alternator, which is sprung to apply tension.

The first gen explorer (or mine at least) has the tensioner directly under the alternator and to the right. The idler pulley is under the alternator, but much lower. I'll post a picture of the routing diagram. I just have to remember to do so.
 






Took me a while, but I remembered. Here's the belt routing diagram for my truck.

IMAG0098.jpg
 






Ok.... so, in your engine, they swapped the idler and tensioner positions. Interesting. I like the tensioner on top better!

That said, I don't have any great explanation or reason for the idler in your case. I can say very generally that, with serpentine belts, it's better to avoid long spans of unguided belt because it can sometimes allow a belt to jump a pulley. But, this is not an enormously long span. You said you have been driving it like this for a while with no problems, and I see no problem in continuing to do so.

LOL, got my little French lesson today too! Good Luck with your MOTEUR!
 






Bit of an update. I realized that I could just go to a part pulling yard for the bolt. Nearly knocked myself out with a facepalm when I remembered that. Going to see if I can find a 4.0l OHV motor with a good pulley and take the pulley itself and the mounting hardware. I'm mildly familiar with bearings. I've taken apart skateboard bearings and reassembled them many times. I'm curious if I can do that with the bearing that Ford installs stock.

I also have an unrelated question I don't really think is worthy of a new thread. If I pull a part from my truck and it has a motorcraft brand across it, is it safe to assume that it is a replacement part and did not come from the Ford factory with the truck? I would think that it would say Ford if it was a stock part, not Motorcraft. (I know they're interchangeable and both from Ford, but that isn't really what I'm questioning)
 






I have no idea if factory parts are branded or not... I'd buy a new pulley myself, but if you want to play with the bearing, if I recall, it looks like a standard sealed bearing. I wouldn't re-use a pulley from a junkyard myself... they're about $20 new.
 






I have no idea if factory parts are branded or not... I'd buy a new pulley myself, but if you want to play with the bearing, if I recall, it looks like a standard sealed bearing. I wouldn't re-use a pulley from a junkyard myself... they're about $20 new.

I will be buying a new pulley. I'll update once everything is installed and I've driven for a couple of days. I'm curious to see if replacing it will calm some of the engine vibration.

Also, a word to anyone who found this thread because they have the OHV 4.0l and had their idler pulley fail. Apparently, you can just remove it and drive to the parts store. Lol.

Edit: Forgot to add the picture I took with the fan and shroud out.

IMAG0089.jpg
 






FYI, I dont know what year they (FORD) made the switch, but the 97' 4L OHV has the tensioner on the side, and the idler on the top.
 






Ford makes motorcraft parts
 






Ford makes motorcraft parts

I tried wording it in a way so people would understand that I already know Motorcraft is made by Ford. I'm basically asking if any Ford Explorers left the factory with parts installed that had the Motorcraft brand name on them instead of Ford. My original reason for asking is because I pulled my PCV valve and found out it has Motorcraft printed on the side instead of Ford, which would lead me to believe that it has been replaced in the past.
 






Ok.... interesting! I did some research on these two layouts. Your belt arrangement, if you try to find that tensioner on a parts website, that style tensioner is used in 1991-1992 Explorers, and then they reversed them so the idler is on top and the tensioner is below the alternator for 93-94. Now, as I understand it, Ford was a bit relaxed about matching engines and years. They may have produced an early 1993 Explorer with a year 1992 engine. You might bear that in mind when you shop for parts.

At any rate, I was about to suggest replacing the tensioner while you are in the neighborhood with the belt off, but they run about $50, and it's pretty easy to get to, so maybe not.
 






That set up with the belt tensioner on the top looks like it is a real pain to get to the thermostat housing. Looks like it is right in the way of the bolts.
 






Ok.... interesting! I did some research on these two layouts. Your belt arrangement, if you try to find that tensioner on a parts website, that style tensioner is used in 1991-1992 Explorers, and then they reversed them so the idler is on top and the tensioner is below the alternator for 93-94. Now, as I understand it, Ford was a bit relaxed about matching engines and years. They may have produced an early 1993 Explorer with a year 1992 engine. You might bear that in mind when you shop for parts.

At any rate, I was about to suggest replacing the tensioner while you are in the neighborhood with the belt off, but they run about $50, and it's pretty easy to get to, so maybe not.

I actually just did a belt change. You may have noticed the belt in the last picture was almost completely split into two. That wasn't going to fly with me.

As far as the tensioner goes... I dang near broke my wrist holding the pulley in place so I could put the belt on. The tensioner has loads of resistance, so I'm going to assume that it's doing its job well. Especially since I don't have any obvious belt slack while running, even with the idler pulley MIA.

I had actually planned on replacing the tensioner before I did the belt change. I decided not to when I felt how strong the spring still is.
 



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I didn't notice the split, I thought it was a mark from manufacturing. Yeah, I concur with not changing the tensioner. It's hard to say when they are about to go... the few I have had to replaced just failed catastrophically, broken spring. I think I had this one time in my 10 years with my Explorer.
 






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