possible blown engine 98 GTI

[toddfw2003]

Yesterday I was riding my ski and noticed that it was idling very low. today I took it out again. while riding it boughed out and wouldnt excellerate for a minute or two and then took off like nothing happened. about an Hour later it started making alot of noise and came to a stop while running. The engine got very loud like it sounds when you run it with the seat off and then it died and wouldnt restart. it doesnt even turn over. took the plugs out and it still wouldnt turn over. Any ideas?

 

[- BiRkS_]

remove the jet pump and see if the engine will turn over. But by the sounds of it, you might have ripped the rod out of one of the pistons. Check the sides of the block for any chunks or "ventillation" If no cracks, you may be able to rebuild your core.

 

[toddfw2003]

I didint see any chunks or cracks. I noticed my oil tank waws still pretty full. I am thinking the oil pump failed. Does it idle poorly when it isnt getting oil?

 

[- BiRkS_]

Very, extremely rare for oil pump to fail, unless you had a cracked injection line. I wouldn't worry about that right now, concentrate on isolating whether or not the engine can turn freely or if its locked up. Remove the rear PTO (grey cover) and see if you can turn the engine over by hand (both ways) if you hear a clunk/locks up, it threw a rod. If its locked tight, even after removing the jet pump, send it out to be rebuilt. Seized either happened from a severe overheat, lack of oil, or super lean condition, resulting in pre-det and overheating.

IMO the low rough idle was a crack starting in the piston and low compression on that one cylinder, the more you ran it, the louder it got (crack widening-more play) and finally, the rod finally separated from the piston. OR the bearings started to seize up on the pump.

Once you determine the failure, then find the cause(s)

 

[toddfw2003]

It only got loud the last few seconds it ran. The bearing siezing on the pump makes sense because it bouged down for a few minutes and then took off about an hour before it perm died. will a siezed pump blow the engine?

 

[- BiRkS_]

No a seized pump will not blow the engine, but it has been known to strip the splines out of the PTO. Remove the pump and see for sure what is going on.

 

[dperkinstx]

Todd & I are working on his Doo today. We pull off the head and it looked very good. Cylinders are nice and smooth. There's a small amount of metal shavings on top of pistons. The tops of the the pistons have a couple small gouges in them.

We hit the start button and saw the pistons barely move.

We remove the jet pump. Out of the ski, the pump turns freely. The motor still doesn't spin over.

Next step - remove the cylinders to see what the pistons and rods look like.

 

[dperkinstx]

The rod on the rear cylinder was seized to to crank. I hit the piston a few times with a rubber mallet and got it to free up enough to turn the motor over. The front rod looks to be fine. Was this an oiling issue?

 

[- BiRkS_]

Probably. Does the crank look heat damaged? Inspect the little oil line that goes to the PTO cylinder. Is there any air bubles, or any oil in there at all? Its also possible for a needle bearing to shatter, but that is normally due to lack of oil/water contamination.

Time for a new crank unfortunatly. Inspect the cylinders and measure the piston-cylinder wall clearance and that will determine weather you should bore it out, or slight hone and re-ring. How are the pistons? are they scored at all?