VW 97?Jetta GL This has me baffled

timing-belts
belts
starters

#1

Greetings from Jacksonville, FL



VW 97?Jetta GL, It?s a gas engine not diesel. Although not a mechanic I?ve turned enough wrenches. This has me baffled.

This is the first VW I?ve owned. I?ve never had a car that I had to take so many parts off to fix common repairs.

The engine will not start. You can hear the starter motor turning and see the timing belt and engine turn. It?s like there is not a spark or fuel or compression.

The noted problems (consumer reports) were electrical (fan relay module) and ignition (ignition module) repaired months before. Actually I direct wired the cooling fan for a couple months, until I could find a fan relay module.

The car died while driving. I heard a brief flapping sound like a belt break. The starter would turn but not the engine over.

The timing belt was shredded but not completely off or broken.

The engine turns easily by handle without excessive resistance. Timing belt replaced. Dead center aligned in three check points.

Starter replaced, starter module replaced, battery checked, plugs, wire distributor checked.

Could this be something that happened before the car died and not have anything to do with timing belt issue?

Advice or Suggestions?

Tom


#2

You may be in big trouble on this. A broken or shredded timing belt on an interference engine will lead to bent intake valves. This will allow the starter to crank the engine over very easily as if the spark plugs were not installed even after a new belt is installed.

The flapping sound you heard may have been the brief rattle of valves hitting pistons. Ouch.

To verify this, bring a couple of cylinders up to TDC on the compression stroke (with the spark plugs removed) and apply compressed air through the spark plug hole. If the intake valve in that cylinder is bent then you will hear air hissing back out the intake.

You could also run a compression check or remove a valve cover. Generally if an engine suffers valve damage the valve lash (adjustment) will be very loose as the valve is not able to close completely.


#3

I agree with OK4450. Although the belt was not completely broken if it was shreded badly it could easily have slipped a few teeth which caused valve damage just before the engine died. a compression check will easily verify this problem.
~Michael


#4

After a little bit of internet research with your prompt I suspect you are correct.
I?m now a bit more educated on interference engines. Why it?s different, the reasons and why it?s not commonly used. It?s one of those ?of course they would use it? kinds of realizations based on the other engineering and reasoning oddities of this car.
Well?geez? this just strengthens my love & hate & disdain relationship with the brief ownership of this car. I?ll wait until the Misses has your coffee before mentioning this to her.
I think now, this 50 year old grey head will just go mow the lawn in high humidity. Maybe I?ll also schedule an unnecessary colonoscopy.
I sincerely appreciate your time to answer this question.
Stay tuned,
Tom


#5

This is why I’m a big fan of chains instead of belts.
I also think an interference engine is a stupid way of doing things. There’s a somewhat technical reason (better breathing for the engine basically)used for why they do this but I think it’s pointless for any perceived benefit.

My son owned a 2.3 Ford and when the belt popped on it some years ago (yep, call Dad), no damage was done as these are non-interefence, or “free wheelers”.
Less than 30 minutes on the side of the road and voila; motor on home.

One would think they would just design some valve reliefs in the piston tops if they wanted to run them that close.


#6

That would significantly increase crevice volume ala increased emissions. EPA holds the trump card.