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The final two weeks, I wrote about repairing the exhaust in my recently-purchased 2008 Nissan Armada and getting the automotive inspected. With it authorized, its intermittent Test Engine Gentle (CEL) concern pale into the background, and the punch listing of wants turned: 1) alternative of the entrance struts (it banged loudly over uneven terrain), 2) diagnosing and addressing plenty of minor leaks, and three) coping with a loud metallic rattle from the entrance of the engine, nearly actually related to the serpentine belt path. As belts are a part of my “Massive Seven” issues more likely to strand a automotive, I addressed this one subsequent.
The so-called serpentine belt on a contemporary automotive is a really completely different beast than the quaint “fan belt” on a classic automotive—that previous slim V-profile belt that spins the alternator, water pump, and the pump’s pulley-mounted fan. Until you personal an air-cooled Volkswagen, the place belt pressure is modified by eradicating washers to make the groove within the pulley shallower, V-profile fan belts are manually tightened by pivoting the alternator on a tensioning observe. Loosen the bolt that holds the ear of the alternator to the observe, pivot the alternator to slip it on the observe till the belt is cosy, tighten the bolt, accomplished. It takes possibly a minute. If the belt snaps, changing it’s trivial. You simply have to cross the brand new belt across the fan, loosen the alternator’s tensioning bolt, put the brand new belt on the crank, water pump and alternator pulleys, and pressure it. If the radiator has a fan shroud, it’s somewhat tougher to get the brand new belt across the fan, but it surely’s nonetheless a straightforward roadside restore.
Manually-tensioned V-belts are easy, however they do have points. Each the alternator and the stress observe usually have rubber bushings in them, and with age, warmth, and oil, they put on out, inflicting the alternator to cock ahead at an angle, which makes it so the belt won’t ever keep tight. In some unspecified time in the future the belt could start to slide, which might trigger the water pump to cease spinning and the coolant temperature to go into the purple. As well as, automobiles that had what had been then luxurious equipment like energy steering and air con usually had separate V-belts for every, whose pressure wanted to be adjusted individually.
Within the Nineteen Eighties, issues swung within the course of automobiles having a single, broad, automatically-tensioned, grooved serpentine belt—so referred to as due to the snake-like path it takes by way of all of the pulleys. Serpentine belts don’t require pressure adjustment. As an alternative, a spring-loaded or hydraulic tensioner has a pulley that leans in opposition to the belt. Along with the pulley on the tensioner, there could also be one other loafer pulley that routes the belt. Typically, if a automotive has a serpentine belt, there’s just one and it runs every little thing, however there are exceptions—my 2003 BMW E39 530i has two, with the second working the A/C compressor, and every having its personal tensioner.
The large benefit of serpentine belts is that they’re maintenance-free (if by upkeep you imply manually adjusting the stress). And, as a result of the alternator doesn’t want to supply the stress adjustment, it mounts rigidly, so it’s far much less more likely to cock from worn bushings. However as with most issues, there’s no free lunch, and a serpentine belt creates a number of challenges.
The primary is that the serp belt, like several belt, is a normal-wear-and-tear half that must be changed, and as is the case with many issues on newer automobiles, that’s far tougher than with an old-school V-belt as a result of tightly-packed nature of parts in trendy automobiles and the torturous path the belt usually takes. On rear-wheel drive automobiles with longitudinally-mounted engines, the tight entry makes it troublesome to even see the belt, a lot much less take away it, with out first eradicating parts just like the air field.
On front-wheel-drive automobiles with a transverse-mounted engine, as a result of there isn’t a belt-driven fan aimed on the radiator, electrical radiator followers are used. You’d suppose that will translate to a bonus that the belt isn’t hidden inside a fan shroud, however on our Honda Match, the belt is so near the facet of the engine compartment that it’s essential to take away a wheel and the internal fender liner to entry the belt and pulleys.
Along with the belt itself needing to be periodically changed, the tensioner pulley (and the loafer pulley, if there’s one) spins on bearings, and over time, they put on out. The indication usually begins as a high-pitched whine, transitions right into a marbles-whipping-around-a-metal-bowl sound, then settles right into a screechy metallic howl because it nears failure. And the tensioner itself can fail, although that’s much less frequent.
The third concern is that changing the belt requires relieving the stress by rotating the tensioner in the wrong way it’s utilizing to pressure the belt, and that’s usually not simple, each as a result of it’s not clear the place or how you can seize it (some tensioners have a hex-head bolt you set a socket on, others have an Allen key or a Torx socket, and on some you seize the central nut on the pulley itself), and since accessing it and having the ability to transfer a long-handled ratchet wrench far sufficient to de-tension the belt is troublesome. You usually want to go looking an fanatic discussion board to search out out which method your automotive requires.
One other factor to pay attention to is that whereas V-profile belts at all times sit within the V-groove of a pulley, one of many issues that allows serpentine pulleys to be so, uh, serpentine is their potential to wrap round pulleys in both course. The crankshaft pulley that offer belt energy and issues that use energy (the alternator, energy steering pump, A/C compressor) at all times have a grooved pulley with the belt’s grooves sitting in it, however the tensioner and loafer pulley could also be grooved or could have a flat floor that presses in opposition to the again of the belt, relying on the belt routing that’s required.
I encountered all these points on the Armada. One thing within the belt prepare was clearly making noise, significantly on chilly begin. It wasn’t but at screechy howl; it was extra like a hole metaling ringing. I used my mechanic’s stethoscope and located that each the tensioner pulley and the facility steering pump had been loud (the steering additionally groaned when chilly, additional implicating the PS pump). Nonetheless, different issues within the belt chain—the alternator, the water pump—can actually make noise as properly.
There’s a method you should utilize to isolate the issue, or at the least get knowledge that corroborates that of the stethoscope. The trick is to de-tension the belt, fastidiously lay it to the facet of 1 element at a time so that you don’t lose the belt routing, and check every element by spinning its pulley by hand in addition to grabbing the pulley and checking it for play. I did that and instantly discovered that the bearing within the tensioner pulley was worn to the purpose of noise and apparent looseness. Surprisingly, the facility steering pump felt advantageous.
So, what to do?
While you discover a unhealthy tensioner pulley, you’ve gotten a number of decisions. You possibly can change solely the pulley, or you should buy a brand new tensioner with a brand new pulley hooked up, or you should buy a equipment with a brand new belt, tensioner/pulley, and loafer pulley if there’s one, and do all of it. The Armada’s belt seemed completely advantageous with no cracks or dry rot, and the loafer pulley was quiet. I often select the money-saving route, however as a result of there was a break within the climate the place I may do the restore, and Amazon may get me a Gates belt-tensioner-idler equipment subsequent day for $115 (whereas the a la carte choices had longer transport instances), I opted for that.
The one energy steering pump I may get next-day was an unbranded Chinese language-made considered one of questionable high quality, so despite the fact that it made sense to tug the belt off and do the 2 repairs collectively, I separated them and ordered a well-priced, low-mileage OEM Hitachi PS pump from a New England recycler, realizing it will take two days to get right here.
I’d already discovered how you can de-tension the belt to do the element check, so eradicating it was simple. I first downloaded a picture of how the belt routed round all of the pulleys, then verified that it was appropriate for my car. I noticed that the Armada is somewhat uncommon in that the mechanical cooling fan (and its viscous clutch) doesn’t journey on the entrance of the water pump however by itself pulley, basically making a second loafer pulley, so it wasn’t my creativeness that the belt path appeared significantly convoluted. Luckily, the engine compartment within the Armada is large enough that every little thing was accessible with out having to do something like eradicating the fan shroud, so changing the tensioner meeting and the loafer pulley was simple.
What was far tougher than I anticipated was getting the brand new belt on. I foolishly thought that, to string it onto the pulleys, all I wanted to do was cross the belt between the fan and the shroud and pull it over the fan. It took me over an hour to totally perceive that the one pulley that’s “contained in the fan” is the fan pulley itself, and that the fan pulley was clean, so it wanted to run in opposition to the again of the belt, not the grooved half. After a number of makes an attempt, I discovered that the trick to placing the belt on was to take a loop of it oriented with the grooves going through outward, cross it over the fan, then put the flat again of the belt on the fan pulley. The whole lot else may then be positioned on its pulley.
Besides, in fact, the tensioner. New serpentine belts are usually a lot tighter than previous stretched belts, requiring the tensioner to be rotated a lot additional again than was wanted to launch the previous belt. Whereas I used to be in a position to launch the previous belt utilizing a ratchet positioned from the highest of the engine compartment, getting sufficient clearance to place an 18-inch pipe on the tip of the ratchet deal with required me to do it from beneath the automotive. I additionally employed the trick of utilizing robust clothespin-style clamps to carry the belt onto pulleys that it saved sliding off throughout belt routing.
Getting the belt on was sufficient work that I didn’t look ahead to having to do it once more when the alternative energy steering pump arrived. Though I used to be sure that I wanted to interchange it, I gave the pump a glance whereas I used to be underneath the automotive. I observed that one of many bolts on the pump bracket was free, so I tightened it. And, though the entire concern of fluid leaks was a separate activity, there was an apparent and non-trivial leak of energy steering fluid from the place one of many rubber PS hoses mated to a steel line. The Armada makes use of spring-style, constant-tension clamps for all of the coolant and energy steering connections. Whereas I perceive the speculation behind their use, I hate these clamps, as in conditions like this, there’s no option to tighten them. I used pliers to loosen the clamp, moved it backward on the hose, took a traditional worm-screw-style clamp, opened it up, slid it over the hose, closed it, and tightened it down.
I then began the Armada. Not solely was the ringy rattle from the belt tensioner pulley gone, so was the noise from the facility steering pump.
No method!
I believed it was a fluke, so I waited till the next 32°-morning and tried it once more.
Quiet as a church mouse.
I’m not sure whether or not the facility steering noise I used to be listening to by way of the stethoscope was only a rattle from the bolt free on the bracket, and whether or not the groaning on chilly turning was attributable to strain loss from somewhat fluid leakage, however for now there’s nothing incorrect with it. I have to determine whether or not to spend the transport to return the $80 used energy steering pump, or put it on the shelf within the storage for when the factor actually does fail.
So. Armada exhaust? Performed, at the least for now. Belt-and-related-accessory noise? Performed, at the least till the facility steering pump rears its head. Subsequent week: fluid leaks.
***
Rob’s newest ebook, The Greatest Of The Hack Mechanic™: 35 years of hacks, kluges, and various automotive mayhem is obtainable on Amazon right here. His different seven books can be found right here on Amazon, or you possibly can order personally-inscribed copies from Rob’s web site, www.robsiegel.com.
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