Before I begin this mechanical manifesto, does your motor vehicle have a timing belt, and when should it be changed? If you don't know, dig out the owners manual and check it out.
I've enjoyed 100,000 blissful miles behind the wheel of my 2003 VW Golf TDI diesel car. Dang near nothin' broke- the repair list includes nothing but assorted bulbs, three glow plugs, a set of tires, and a deer inflicted ding in the hood. But vehicular bliss was about to end...
VW demands that the timing belt be replaced at 100,000 miles, under threat of serious mechanical mayhem if a worn out belt causes valves to meet pistons in a violent manner. In current dollars, that's at least a $3000 repair. Thus VW is able to extract, in an automotive protection racket, a thousand dollars or so to replace the belt before it breaks.
If only it were that simple... wander the online gearhead forums and you'll find that even the dealership pros are having trouble with timing belt replacements. Stories abound of consumers duly taking their cars to dealerships and laying out a thousand $$$ for a timing belt replacement... Only to be given back a car that barely runs or breaks down almost as soon as it's out of sight of the dealership. Indy shops are having problems with timing belt replacements too, so many of us gearheads have resorted to Do It Yourself (DIY) timing belt replacements.
So I stocked up- New timing belt as well as all the rollers, tensioner, bolts, and water pump that the dealerships often don't bother with. Those are the "details" that break after a dealer-done timing belt change. I tooled up too- locking devices to hold all the relevant rotating bits in place so they'd stay in time as the new belt is installed. Even spent $250 on a diagnostic program and cable so I could retime the engine and do a bunch of other diagnostic stuff on the car.
I, it turned out wisely, put off the timing belt replacement until summer when I didn't absolutely need the car. So with two manuals and a bunch off internet how-tos in hand, I dug in. Working a couple hours a day, just the disassembly took a week- why does the right front wheel, fuel filter, washer bottle, power steering resevoir, coolant overflow tank, and dozens of wires and hoses have to be moved to perform regular maintainence?
By the book, I installed the new belt, noting that the old belt was barely worn and could have gone thousands more miles. I checked and rechecked my work. And after a month of working a couple hours a day a couple days a week, I had the new belt on and everything else back in place. After carefully turning the engine over by hand to insure that nothing was amiss, I started up the engine.
It ran fine for a few seconds and died, but I expected that- The filter had been removed and needed to reprime itself. So I spent days getting the filter reprimed, finally noting that I had reversed the in and out fuel lines to the injection pump, which VW hadn't bothered to label.
With the engine now able to run for more than a few seconds, I checked and reset the timing. Then I went for a test drive before I reinstalled the hood and the last of the covers. It was a disappointingly slow test drive- the engine was way down on power. After a couple miles it finally threw a code- P0299, insufficent turbo boost. Checking with the online gurus, that means I probably have a vacuum leak, intercooler pipe leak, or one of several valves and a servo may not be working. That means unless I find the failed part early I'll be spending at least another week trying to make the car runs right.
All because I dutifully perform the manufacturers recommended maintaince, replacing a timing belt. So why do manufacturers put stupid junk like timing belts on engines? For the last century or so, timing CHAINS have dutifully connected crankshafts to camshafts and insured continued internal combustion. Timing chains aren't easy to replace either, but by the time they wear out the whole engine usually needs rebuilding anyways.
So again, why does any manufacturer use timing belts when they appear to be a "gotcha" at 100,000 miles or so? Well, I've got a conspiracy theory handy, and it's somewhat plausable. Say you're an auto manufacturer, and sales are slow because the economy is down and consumers can't afford new cars. The consumers, given there druthers, would keep their cars for 200,000 miles or more. So you save a few bucks by using timing belts instead of chains in the vehicles you manufacture. That thousand $$$ timing belt replacement serves as an incentive to make owners trade for a new vehicle before the timing belt replacement is due. And in case the owner ignores the manufacturer's warning of mechanical doom, the manufacturer designs an "interference" engine, where the valves and pistons are so close together that a broken timing belt will destroy the engine. Call it timing belt terrorism if you will, as manufacturers plant mechanical minefields inside your engine to insure you trade or expensively replace before they explode.
It doesn't have to be this way. I'm infuriated enough to have studied up a bit on who uses timing belts and who uses the more durable timing chains. For example, Ford, one of my favorite car makers, has shied away from timing belts in most of it's engines. And the premium automakers hardly use the dreaded timing belts at all. Having had my fill of timing belts as well as turbochargers and other automotive tech overkill, I'm tempted to wander by my local Ford dealer and order a new 4 cylinder Ranger with a stick shift before they close the order books in september. At supplier prices, of course. 25 MPG don't sound so bad when you've got no timing belts and turbos to worry about and you can haul a half ton in the back!
So next time you're shopping for a car, new or used, see if it has a timing belt. Unless it's a couple hundred dollar beater that has at least 50,000 miles left on the belt... Run, don't walk away!