Timing belts were new to me since model year 1980, been replacing these for family, friends, and myself, most recently on my own 1988 Supra.
First area of concern is to learn if you have a so-call interference or non-interference engine, the former, if anything goes wrong with the belt, the pistons will crash into the valves, this is major. First ones were always non-interference, interference is tantamount to insane.
Was never the belt itself, seem to last forever, always the tensioner and/or an idler pulley that is the major cause of potential problems. Tiny ball bearing in there with a thin seal that can lose its lubrication, with a timing chain, it has constant lubrication and always renewed with every oil chain.
Main concern with my own Supra was age, only 45K on it, and was a good thing, the grease in both the tensioner and idler pulley was rock hard. Other concerns is the type of cage the bearing is using, can be plastic, stupid, tack welded metal cage, bit better, some some are not tacked very well, best is riveted. With plastic, heat can melt it, locks the balls, this will break the belt.
Other concerns, never seem to make the timing chain cover decent, road debris gets inside, what a mess. Yet another, need camshaft seals that age, sure don't want any oil on that belt. Other concerns are what type of material they are using for the sheaves, a Ford used a piece of plastic for the idler, gets hard with age and broke.
Yet another is do they show timing marks on the camshaft and crankshaft sprockets, some don't, stupid, need special tools to align this, just one tooth off, you put it all together and your engine won't run. Only find this out by getting your hands on a shop manual first.
Call the ball bearings for the timing belt, limited lubricated bearings,just a fraction of an ounce in these things. But this is only the only spot, also on these single drive belt systems. PS pump is gone, but still have the AC compressor and an over 100 ampere alternator that can put an extra 4 HP on that single belt. Weakest link in the chain is the water pump, the more you use your AC, the quicker it will wear out.
Really loved my 04 Cavalier 2.2L Eco engine, while an 80 buck tool was required to replace the water pump, never needed to buy one, was directly driven by the timing chain. That water pump, belt driven sees the same load as the alternator and the AC compressor. If you don't keep your condenser clean, R-134a refrigerant whose pressure increases exponentially with temperature puts a severe load on that AC compressor that is reflected to the water pump.
Engineers know all this stuff, but have to obey bean counters. Never had problems with that 04 Cavalier water pump, with even over 160K miles, was still running great, but road salt ate away at the rocker panels. Considered welding on new ones, but after I removed the carpeting, nothing left to weld them to.
Was disappointed when I read on the 1.4 L engine, put that water pump back on the belt, but since I had $4,800 on my GM Card, purchased it anyway, been through this before. One major disappointment, could no longer clean my condenser from the top, had to do this from the bottom. Nothing worse than city driving for excessive engine heat, just kept my AC off in these situations, I did not die.
Ha, was in 2014 my Chevy dealer called me, knocking off an extra 5K off the diesel, at this time diesel fuel was around a half a buck more expensive than gas, and after I read about that timing belt, said, no thanks. Then if your DEF tank runs low, it kills the engine! Ha, where is that compact spare?
