Nissan GU Patrol Belt Tensioner

Following on from an earlier post about Made in China, I thought I’d add another part to this as I recently experienced another side of made in China. As I noted previously, there are many products made in China that are of excellent quality and performance, but there are also many that are anything but excellent quality and performance. I was reminded of this when the fan belt in my Patrol started to squeal, which was a clear indication that it needed to be replaced. The fan belt is of the serpentine belt design and kept in tension by a piston on a pivoting tensioner assembly. It’s a relatively simple design and generally foolproof, but the tensioner piston can eventually start seizing, especially if you do a lot of water crossing and/or mud holes. It is sealed, but it can still seize and that causes the squealing (by not tensioning the belt enough). It’s not the idler pulley (I/P) bearing as many believe that causes the noise.

Nissan Patrol Fan Belt Tensioner Schematic

Nissan Patrol Fan Belt Tensioner Schematic

Anyway, around three or so years ago I’d bought an aftermarket tensioner and belt off eBay as I was getting a squeal or squeaking on and off. But as it wasn’t a persistent squeal, only giving a hint after a water crossing and generally stopping when things dried out, I’d put it aside. But in December 2019 the squealing became quite loud and persistent, so I decided to remove the old tensioner and belt and install the one I’d bought way back when. Everything went well and I now had a quiet vehicle once again. That’s until I didn’t. After my first drive, I was now happy that there was no noise from the engine bay and all was good. However, later that same morning I went to drive off to the local shops and the squealing was back. It was so bad that I didn’t want to drive it anywhere. For some reason, between the morning drive and the later on, something had changed and not for the better.

Aftermarket Nissan Patrol Fan Belt Tensioner

Aftermarket Nissan Patrol Fan Belt Tensioner

Genuine Nissan Patrol Fan Belt Tensioner

Genuine Nissan Patrol Fan Belt Tensioner

So now I started investigating what could be wrong and all things seemed to initially point to the turbocharger. The only thing that I could do was take look closer at the turbocharger but, as my wife was away at the time, I couldn’t listen to the turbocharger and rev the engine at the same time. At idle, using a through-tang screw driver, I listened to both sides of the turbocharger housing and couldn’t hear anything that might indicate a failing bearing. So next day when my wife was back home, I repeated the exercise, this time with my wife bringing the engine revs up to the point where the squealing started. Again, as far as I could hear, there was nothing amiss with the turbocharger. Going back under the Patrol and listening there, the squealing was quite pronounced. I tried to add tension to the fan belt, but then the squealing stopped of its own accord. OK I thought, the new tensioner and belt needed time to settle in and that was the source of the noise.

Genuine (R) vs Aftermarket (L) Nissan Patrol Fan Belt Tensioner

Genuine (R) vs Aftermarket (L) Nissan Patrol Fan Belt Tensioner

Genuine Nissan Patrol Fan Belt Tensioners

Genuine Nissan Patrol Fan Belt Tensioners

So next morning I did my usual and warmed up the Patrol before taking my hounds to Mossvale Park for a run and, going to the park and on return, there was absolutely no noise coming from the engine. So maybe that was it, it needed a settling-in period and problem solved. But not so. After once again sitting for an hour or so and starting up again, the squealing resumed. It was clear that this aftermarket tensioner and belt must be the cause of the noise and most likely while fairly cold, was tensioning reasonably well but when warmed up was failing to do its job. So back onto eBay and Google to find a genuine tensioner (I already had a genuine fan belt as a spare) and put in an order. In the mean time, I decide to remove the aftermarket fan belt to compare it again to the original and that’s when made in China failed.

Nissan Patrol Fan Belt Tensioner - Cheesy Alloy

Nissan Patrol Fan Belt Tensioner – Cheesy Alloy

While trying to take the tension off the belt using the provide 19mm nut that forms part of the tensioner assembly, the corners simply stripped. The nut on the tensioner wasn’t exactly 19mm and was, for all intents and purposes, made from hard cheese. This is one area where some made in China products can look and feel exactly like the genuine thing, but what it’s actually made from can make a huge difference. In this case the alloy was no where near the standard of the genuine product and while the assembly itself may have stood the test of time, it certainly wasn’t of the same quality. Removal fortunately didn’t prove a chore as all I needed to do was remove the two holding bolts and off it came. I then compared the aftermarket belt once again with the original belt and there was a noticeable difference, with the aftermarket belt being slightly longer, which may well have been the major issue. But I can’t fathom how it stretched in such a short time. And when I compared the aftermarket belt to a genuine new one, I also notice a big difference in the ribbing of the two, as the photo shows.

Nissan Patrol Fan Belt Tensioner - Genuine Belt (top) vs Aftermarket Belt (bottom)

Nissan Patrol Fan Belt Tensioner – Genuine Belt (top) vs Aftermarket Belt (bottom)

Anyway, I put the original tensioner and belt back and once again things were a lot better, albeit with a minor squeal every now and again. It just goes to show how you need to be careful when buying aftermarket products over genuine. The cost factor is always a temptation, but you really do need to consider whether it’s worth the money that you save over the risk that the product may bring. Finally I received my genuine tensioner and I thought things would be sweet. However, The situation didn’t improve and the noise was as bad as ever. One thing that was immediately evident was that the piston on the new genuine tensioner was very weak. The original piston and that of the aftermarket one were at least three times firmer to move. After swapping belts and tensioners to find a setup that worked, I finally took the aftermarket piston off the housing and combined it with the original housing. The aftermarket piston was about 5mm or so longer and tensioned the belt a lot better than the new genuine one, where the belt would move inwards almost 20mm when pushed.

Genuine Nissan Housing with Aftermarket Tensioner

Genuine Nissan Housing with Aftermarket Tensioner

So I sent the genuine tensioner back to the seller and received a new one in return and things were were once again good. There’s one thing to note, and I’m not sure if it easy to see in the photographs, but the genuine tensioner is also made in China and when I was installing the first one, it too burred a bit on the edges of the hex nut. The old tensioner was as good as gold throughout the numerous installs and uninstalls it went through. There was some initial squealing, as the manual indicates, but after a bit of idling and revving, the noise abated. As a footnote, when I started looking for a new tensioner, there appeared to be one for the Di Patrol and one for the CRD Patrol. I have no idea whether I received the wrong version when I ordered mine so many years ago, but either way, cheese is cheese. For those who are constantly going through water and mud and wearing out their tensioner piston, you can get a manually adjusted one from here, which provides perhaps a better solution for those wanting a simpler option.

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