Broken timing belt, interference engine--mechanical novice here

[CuteBrute]

I own a '92 Jetta GL, 4 cylinders, 1.8 liter. The timing belt broke and a mechanic quoted me $1000 to fix it. It has an interference engine.

I'm not going to spend a thousand dollars on repairs, but I'd like to at least try fixing this car before dumping it. I'm a mechanical newbie; I know how to change oil, and that's about it. Normally I wouldn't even attempt this sort of thing, but I've got nothing to lose in this case.

So my first question is, how do I tell if the engine has been damaged or not? What do I take apart, and what do I look for, exactly? I need to know this before I bother buying a new timing belt. Please keep in mind you're talking to a guy who knows very little about cars. Thanks.

[yogi_123rd]

An interference engine means that the valves can come in contact with the pistons if the timing is not right.

To see any damage done to the engine will require removing the cylinder head and visually inspecting the piston. Steel valves striking the piston will dent the aluminum piston. If the valve contacts the piston too long, it will poke a hole through the piston.

Alternately, you could do a compression check on each cylinder. If they all holds compression, there is probably no hole.

[CuteBrute]

So if I do the compression test and all the cylinders have equal compression, I'm safe to assume there's no engine damage? If the valves were merely dented instead of pierced, wouldn't the compression read normal?

[moparvwfreak]

92 SHOULD be the last year of the non interfearance 8v. this is assuming you dont have the 2.0l 16v. if it is an 8v NON cross flow you should be able to just retime it and put a new belt on and go.

[inafogg]

hey CB in my experience & if it were me i would first turn the crankshaft
by hand & see if you can feel any resistance(piston contacting valve)
now if you dont you might be ok but not for certain as the valves may have
bent enough to clear pistons.if all seems ok buy a belt & put it on after lining
all timing marks.if it starts great if not do compression test.IMO i would'nt
be cranking engine with out having the valves line up!!the worst case you
have is $35 & a few hrs.invested. good luck!!

[Doug Tatham]

I have the 1.8 liter and was told that it was an interference engine, but from what I can tell they are wrong. The pistons shouldn't have hit the valves. I'd put on a new timing belt, set the timing, and see how it runs. Get yourself a haynes or similar manual before you start. It's not all that hard, but it helps to have some type of guide.

[CuteBrute]

Thanks for the advice so far.

I forgot to mention in my first post that when the timing belt went out, there was no clanging and banging, no sounds of anything being damaged as far as I could tell. The car just quietly stopped running. Wouldn't you expect to hear something if there was damage happening?

I just now took a look under the hood. It's actually the first time I've done so since the problem occurred. There's a belt that runs vertically on the left side of the engine. I had to pull up a plastic cover to look at it. That would be the timing belt, correct? The belt appears to be in bad condition, very cracked, but it's wrapped firmly around the gears; it hasn't slipped off or snapped. Doesn't that sound odd? Or am I just not looking at the right thing? Or could it be that the belt has stopped working because it's too worn to grip the gears?

So there's a chance I've got a non-interference engine after all. I know for a fact that it's 1.8 liter, but I don't know whether it's 16v or 8v, or whether it's cross flow or non-cross flow. How do I check?

inafogg, I just bought a compression gauge, but I think your idea of turning the crankshaft by hand first sounds wise. What do I need to do to reach the crankshaft?

[moparvwfreak]

Originally Posted by Doug Tatham

I have the 1.8 liter and was told that it was an interference engine, but from what I can tell they are wrong. The pistons shouldn't have hit the valves. I'd put on a new timing belt, set the timing, and see how it runs. Get yourself a haynes or similar manual before you start. It's not all that hard, but it helps to have some type of guide.

now there IS a 1.8l that IS an interfearance motor. that is the PL code 1.8l 16v that came in scrioccos, some GTIs and GLIs. they may have been confused about the style motor it was which can happen.

Originally Posted by CuteBrute

Thanks for the advice so far.

I forgot to mention in my first post that when the timing belt went out, there was no clanging and banging, no sounds of anything being damaged as far as I could tell. The car just quietly stopped running. Wouldn't you expect to hear something if there was damage happening?

I just now took a look under the hood. It's actually the first time I've done so since the problem occurred. There's a belt that runs vertically on the left side of the engine. I had to pull up a plastic cover to look at it. That would be the timing belt, correct? The belt appears to be in bad condition, very cracked, but it's wrapped firmly around the gears; it hasn't slipped off or snapped. Doesn't that sound odd? Or am I just not looking at the right thing? Or could it be that the belt has stopped working because it's too worn to grip the gears?

So there's a chance I've got a non-interference engine after all. I know for a fact that it's 1.8 liter, but I don't know whether it's 16v or 8v, or whether it's cross flow or non-cross flow. How do I check?

inafogg, I just bought a compression gauge, but I think your idea of turning the crankshaft by hand first sounds wise. What do I need to do to reach the crankshaft?

this is out of an 89 but it should be the same as your 92 as that was the last year of this body. its a 1.8l digifant injected 8 valve.


this is out of my 90 GLI. it is a 2.0l 16 valve with CIS-E fuel injection. 1.8l 16v similar.




then there is the 2.0l aba cross flow 8 valve, that came in 93 and later cars, which has a similar intake design which comes over the valve cover but since i have never owned an ABA i dont have any pics of that. that one i am not sure of if its interfearance or not.


under the plactic cover is the timing belt. so yes you are looking at the right thing. to get to the crank all you have to do is slide under the car on the pass side and there MAY or may not be a cover there to keep water off your accessory belts. if there is its 2 10mm bolts and a couple of pinch clips that hold it together. take that off, if applicable, and you should see the cramp pulley with a big 17mm bolt head in the middle. you can use a ratchet and extention (3 inch) and a 17mm socket to turn the pulley. it is adviseable to have a helper if you can. i am not sure what tools would be needed to replace a timing belt as i have never done it but i will be here on a rabbit soon. good luck and run that comp test as soon as you can and let us know whats going on.

[Doug Tatham]

moparvwfreak, I have the 1.8L RV style engine. I'm a weekend mechanic and only know the engines that I personally own. Most of the rest of my advise that I give is based on general understanding.
CB, If the timing belt is very badly worn, it may have slipped a notch and got your timing off. Just a guess. It still sounds like a new belt will be all you need. You may want to replace the idler torsion pulleys while you're at it. You'll need a special VW tool (similar to a spanner wrench) for tightening your belt and setting the tension. You can find it online for about $10. Changing the belt can be done by someone with minimal experience, but as I said earlier, I'd get some type of guide for instructions.

[CuteBrute]

moparvwfreak, as far as I can tell my engine is exactly the same as what's in your first pic. So it's non-interference. That's a load off my mind.

Now, when I'm turning the crank, I should feel no resistance at all if everything's working correctly? I mean, it may be hard to turn, but it should be equally hard throughout the full cycle. As long as there's no sudden change in resistance, it's ok?

I should probably make the jump and buy a full tool set rather than keep buying cheap wrenches and sockets singly every time I need a new size. I'll be doing my own research, but do any of you have tool set suggestions?

[CuteBrute]

I've got a Haynes manual here in front of me. It looks like most of the $1000 the mechanic wanted to charge me would have been for labor. You've got to remove a lot of things to access the belt. The actual belt replacement looks easy enough, though.

Just to clarify--if the gears slipped a notch, even without the belt breaking or slipping off, that would account for the car suddenly going dead while I was driving? Is that what you'd expect to happen?

[yogi_123rd]

If the timing belt slipped a tooth or two, the car dies. This happened on my car. The belt slipped two teeth and it wouldn't start. It sounds like that is what happened to your car after you described the belt as having many cracks in it.

[moparvwfreak]

Originally Posted by Doug Tatham

moparvwfreak, I have the 1.8L RV style engine. I'm a weekend mechanic and only know the engines that I personally own. Most of the rest of my advise that I give is based on general understanding.

i wasn't trying to come off that you didn't knwo anything and if i did i am sorry. i know the feeling though about knowing the stuff you have or have had. thats how i am as well.

[Doug Tatham]

CB You'll want to order the timing belt tensioner tool soon because it will take awhile to get it. Kobalt (Lowes high end) and Craftsman (Sears) tools are both great and have lifetime warranties (they don't include loss though). I like to have a good set of 6 point sockets because you don't end up rounding off the nuts. You'll want a torque wrench as well and follow the torque specs in the Haynes manual. You'll need a 12 point socket (17mm) to rotate the crank shaft.
You will want a set of metric Allen sockets for the pulleys and A/C compressor. You'll need jack stands so that you can safely work under the car. It's easiest to remove the pulleys and belts from under the car. Give yourself 4-6 hours since it's your first time to make this type of repair. label tubes and wires with masking tape and a sharpie so you can remember where to reconnect them. If you have a digital camera, take photos before taking things apart to help you remember. This was very useful when I changed my A/C evaporator and had to remember how to route the wires in the dash.

moparvwfreak: I wasn't insulted, I just wanted to make sure people knew to take what I say with a grain of salt. I'm a fairly good mechanic, but I'm not a pro.

[Rothart]

You guys forgot to mention to make sure the distributor drive pulley needs to be kept in one place at TDC. This is a big pain in the ass when you're tensioning the belt.

Also, if your cam and your crank are not timed in sync, your not going to get an accurate reading on compression, but you don't have an interferance engine so it doesn't matter anyway.