Ready for some carnage?

Long story short, my wife and I took our Jetta about five hours from home to get some help with a timing belt replacement. After we had replaced it, I started the car and it ran great. Driving around, warming it up, the oil light came on and started flashing. The car has a decent oil leak so it was nothing new so I jumped out and checked the oil, which was fine, but I added a little just to be safe. Well the oil light kept flashing. On my way back from warming it up the belt must have skipped at least one tooth on the cam and who knows how many on the injection pump due to lack of tension and started running like crap. We got the car back and the next morning lined everything up, put more tension on the belt and got it running great, but the oil light kept coming on. We decided the sensor must be going bad or some wires were wiggled loose or what-have-you and went on our way. About 2.5 hours into our trip on the interstate the engine started making all kinds of racket. We made it into a gas station parking lot where it finally died and wouldn't even crank, which I figured it had probably locked up. Well we started tearing it apart last night and here's what we found when we pulled the pan. Sorry for the crappy pics.



That's the number four cylinder connecting rod bearings, cap, and bolts laying in the pan. This is where it started getting interesting. One bolt was broken in half, one half being in the cap, the other still in the rod. The other bolt, however, was laying in almost perfect shape in the pan all by itself. I have suspicions but want to know what you guys think about that.




This one is kinda hard to see but it's the connecting rod, off the crank, wedged between the crank and the block which was preventing it from rotating. Rotating the crank freed it up, making evident it wasn't locked up.


And the rod...


Surprisingly, the cylinder and piston look fine. I am worried about the head though, with all that slop going on. What do you guys think? Would I be able to see damage? I am going to have it pressure tested at the very least, maybe pull apart depending on what you guys say.





So. What do you guys think? Please feel free to give me any advice on what I need to check or do. I am probably going to get a lower mileage block and rotating assembly from a member on here for less than what it would cost to repair mine.

Also, what are the odds this was just pure coincidence that it happened right after we put a new timing belt?

How many miles on the car? It is usually rod #4 that makes a new window to the world. Looks like you might have gotten lucky that the rod didn't break in the middle causing the piston to stick high in the cylinder which may have saved your head. I would still check the valves in cyl 4, and replace the valve guides and seals while its out, along with a valve seat re-cut.

Hard to tell from the pic, but if the glow plug is flattened at all on the edge the piston did over-travel the top of the bore.

I expected a dropped valve that did the carnage, but that wasn't it obviously.

167k miles. And I did get lucky because there aren't any extra holes. I'll certainly take your advice on the head. The glow plug looked fine so that makes me feel a lot better. Thanks for the advice.

What's blowing my mind is that the oil light came on the first drive after the timing belt. What are the odds? Is there any correlation at all? I can't think of anything.

Piston/valve contact on any of the other cylinders? Look at the valves and the valve reliefs in the pistons before cleaning.
If not, then your T-belt didn't skip any teeth. One tooth on the belt is enough to catch a piston into a valve. When you did the belt, did you pop the taper on the cam pulley? It is very easy to get it off enough for valve/piston contact doing it that way without the cam locking tool.

Either way, it's probably just coincidence that the rod bolts came loose when they did. Were you revving the engine any higher than normal? Such as the first highway trip in a long time in a city car that rarely sees over 30 mph.
A diesel can actually survive quite a while with one rod bolt completely out, as the intake stroke doesn't work against any sort of manifold vacuum, the rod cap doesn't have enormous amounts of force on it, and the one time that it does (TDC between exhaust and intake strokes), the piston crown hits the cylinder head, not flexing the remaining bolt too much. It can last 500 miles this way, sounding like hell and down on oil pressure.

With how that rod looks, I'd be at the very least getting the crank checked for straightness.

There isn't any blatantly obvious signs of contact. Of course I don't really know what to look for but there aren't any out of the ordinary marks that I can see.

I'm not sure I follow as far as "pop the taper"? We did use a cam locking tool.

I'm hoping it works out that I don't have to reuse any of the rotating assembly.

Baxter'sTDI said:

There isn't any blatantly obvious signs of contact. Of course I don't really know what to look for but there aren't any out of the ordinary marks that I can see.

I'm not sure I follow as far as "pop the taper"? We did use a cam locking tool.

I'm hoping it works out that I don't have to reuse any of the rotating assembly.

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Loosening the taper fit between the camshaft and the cam pulley.
If you used the cam locking tool, then probably yeah.

You can see quite clearly on the #1 exhaust valve the half moon of the piston's combustion chamber. That kind of contact mark, and if there aren't any contact marks on the other cylinders, then the cam timing was proper the whole time the engine was spinning.

Going to a PD rotating assembly? Supposedly beefier in every way. IIRC, just swap over the reluctor ring and it's a drop in fit.

Actually that picture of the valves is upside down I guess, not that it really matters. That's the #4 cylinder.

And I guess I don't know as much as I should about PD and VE engines. It's a '99 ALH block that I'm planning on using.

I guess I might as well use this thread to ask about the head gasket as well. Any suggestions on which to use or any tips/threads to look at? I'll probably search it still, I just like getting direct suggestions if I can!

Baxter'sTDI said:

Actually that picture of the valves is upside down I guess, not that it really matters. That's the #4 cylinder.

And I guess I don't know as much as I should about PD and VE engines. It's a '99 ALH block that I'm planning on using.

I guess I might as well use this thread to ask about the head gasket as well. Any suggestions on which to use or any tips/threads to look at? I'll probably search it still, I just like getting direct suggestions if I can!

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You just choose which one based on measured piston protrusion.
Google something like "ALH head gasket selection" and there's a million threads with the values.

I figured. Thanks for all the info so far!

"The car has a decent oil leak so it was nothing new so I jumped out and checked the oil, which was fine, but I added a little just to be safe."

this ^^ is a direct quote ftom the OP's first post .... so the oil light coming on was nothing new ?.... bad oil leak not addressed ?.... if so zero sympathy here because you had knowledge of a potentially fatal problem beforehand

Haha! Thanks. I didn't know a lack of oil would cause a rod bolt to loosen.

The car had plenty of oil in it when it let go but who knows, it could've been from being previously low...

The light is turned out by sufficient pressure, not sufficient quantity.

Which it didn't have sufficient pressure due to a loose rod bolt, right?

Nevertheless, it's getting fixed whether I have sympathy or not!

Baxter'sTDI said:

The car had plenty of oil in it when it let go but who knows, it could've been from being previously low...

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this^^ anytime the oil light comes on while driving you've already driven it too far and the damage is most likely done ... and judging from your first post the oil light was a common sight in your cluster ... and don't put the cart before the horse ... the bolt probably came loose due to a knocking rod from repeated lack of oil pressure....

Hmm. Could be.

Blood, sweat,... and I don't cry! I will stop to take a picture though! Hahaha!

And I found my leak...

How did you not notice that before? Damn, that's nasty.

Oh I knew it was there, but it's my wife's DD so I couldn't just pull it out and fix it overnight. Looking back though...

So, is the storyline looking like this bad seal resulted in low oil pressure which ultimately killed one of the rod bearings (#4)?

What is the history of this vehicle? I really want to understand how to minimize the chances of having this happen to one of my cars.

Well that's the way it's looking. I guess it was just pure coincidence it happened the test drive after the new timing belt was put on.

We bought it with 94k miles, my wife has been driving it for the last 73k miles and about a year ago the rear main started leaking. I'm not really sure why but I guess it's probably irrelevant. I'd try to top it off as often as I could but every now and then she'd call me and tell me the oil light would turn on, usually when she'd turn and all the oil would flow to one side. When she'd straighten out it would go back off. It lasted that way, like I said, for over a year.

SO. To minimize the chance of it happening, make sure to fix your oil leaks and never disregard the oil light!

Theres a reason why its called the idiot light lol just messin with ya... hope it all comes back together.. look at the bright side... its your chance to really make a nice engine out of it all..

peterdaniel said:

Theres a reason why its called the idiot light lol just messin with ya... hope it all comes back together.. look at the bright side... its your chance to really make a nice engine out of it all..

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HA! Exactly. As long as I do it right I won't have to worry about what anybody else ever did to it! (Not that it's any worse than what I've done to it although I'll probably baby it from here on out.)

Hopefully here in the next day or two everything will be going off to the machine shop.

[486] said:

One tooth on the belt is enough to catch a piston into a valve.

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You, sir, are absolutely correct. I guess I'm not gonna get a break on this dang thing.





This is the worst part though.





I wouldn't mind replacing the cam but is the head even repairable??

The turbo is toast as well. Just thought I'd throw that in there. Lucky I had a spare laying around.

Baxter'sTDI said:

The turbo is toast as well. Just thought I'd throw that in there. Lucky I had a spare laying around.

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With low/no oil pressure it was probably a casualty early on. Something that spins at over 100K rpm on a suspension of oil doesn't last long w/o any.

Contact Franko6 about a head rebuild. If anyone can he can.

Cool. Thanks!