NickD,
That's something additional to lookout for, right? Not related to the tensioner? Why do you think the tension pulley only makes the noise sometimes?
Not thinking, but knowing, single drive belt systems have been around for about 30 years now. Like a rope in series with a spring tied between two tree. Hang an excessive load on that rope can exceed the force on that spring, it will stretch as will the tensioner spring. Compressor loads are not constant, more like pulse loads, but not put stress on the tensioner, but any other sheave in the system as well.
Excessive loads caused by either the compressor or the alternator can also damage the water pump bearings causing leaks. So with water pump problems, may not be the water pump, but its the victim of other devices in the system causing excessive loads on the series system. And replacing the water pump is not the solution, the new water pump will see the same stresses.
Very common knowledge in the engineering field dating back more than a couple of hundred years. This is why all vehicles were using multiple drive belts. Heck my 1973 Fleetwood had five belts, P-30 has three and so does my 88 Supra, to isolate these loads, but all common to the harmonic balancer drive source.
So why did they develop the single drive belt system? Only one reason, its cheaper. But if that one belt breaks, kills the entire system. Did have a bearing seize up on my idler driving the compressor that only broke its own belt. Still had the alternator, fan, and water pump working just fine. Just lost AC, but still could keep on driving.
But if that belt breaks in a single drive system, you are screwed to the wall, very stupid idea. You can be stranded in ice cold conditions and die because of this. And some have.
The tensioner can be tested for smooth operation with a torque wrench in two seconds, yet another problem is it pulley with a limited lubricated ball bearing that can seize. This can be replaced separately for ten bucks.
Do you want to learn more stupid changes? Going to hear them anyway, the switch from R-12 to R-134a that was never proven to deplete the ozone layer. Automotive use of R-12 was less than 2% of the entire CFC production, rest was used for worthless stuff. The difference? R-12 pressures increase at a linear rate with temperature whereas R-134a increases at an exponential pressure rate with temperature. A plugged condenser causes extremely high pressures that put severe loads on this single drive belt system. And really augmented by ambient temperatures as well.
Can be a key reason why your tensioner is jumping. Another stupid change is on the harmonic balancer the drive pulley. Some instead of using a solid pulley elected to split that pulley separated by a piece of rubber. Their reason, to cut engine noise by one db or so. But that rubber hardens, breaks, so while the inner section is spinning, the outer remains stationary.
All the ball bearings in the driven components can be replaced, GM made this extra difficult by using an interference fit on the compressor idler pulley to save a 2 cent retainer ring. So far, four different special tools are needed over the years, can't even use the same tool. Then that pulley can shift causing gap changes of either the clutch is burning up by rubbing or has excessive gap so it won't even energize. Stupid, shims were used for years.
Water pump always has been a throwaway item, can't lubricate it, just a bronze bearing with an inner seal on it. Could have made this part separate so that is all that had to be replaced.
So if you are wondering why we are having problems, this is some of the reason, always a reason. And if the idiot cannot determine the cause of the problem, just throwing parts at it costing you a small fortune.
Ha, you got me started again.
