So recently had my serpentine belt break. With my infinite good luck a piece got through the timing belt cover and got wrapped around the crank. By the time i found that that the timing mark was 180 off tdc. But could have spun more than that while i was trying to start the car after the serpentine belt change. After setting the time its still not starting. Triple checked all my marks and all the pins go in as the procedure states so pretty sure im good there. However, there is pretty much constant blowback out of my intake when cranking over. I'm guessing my valves and pistons may have had their first kiss. Thoughts or ways to confirm? I'm a mechanic by trade just not the automotive variety. Learning as i go with this adventure lol.
Timing belt slipped
- Thread starter coryc34
- Start date
2004LB7
Veteran Member
Had this happen to me too. Ended up pulling the head and saw the witness marks on the pistons. If you really want to know, pull the head. Otherwise do a compression test. But you're going to need to pull the head anyways, so, might as well start there. That will also allow you to measure piston protrusion to verify you didn't hurt any rods too
Nuje
Top Post Dawg
- Joined
- Feb 11, 2005
- Location
- Island near Vancouver
- TDI
- 2002 Golf 6MT; 2015 Sportwagen 6MT; 2018 A3 e-tron 6DSG
You're gonna need/want new valves as well.
Bob S.
Top Post Dawg
And rocker arms, possibly cams.
2004LB7
Veteran Member
Ended up removing the head. Every piston has valve marks. No holes or cracks luckly. I bought a parts car a month back so i actually have 2 good spare heads. Waiting on the gaskets to put it all back together. Thank you all for pointing me in the right direction. Things really escalated quickly from a broken serpentine belt lol
Bob S.
Top Post Dawg
Do yourself & the engine a favor as you put it back together: Install a reduced clearance lower timing belt cover & R&R the clutched alternator pulley. What you experienced is, unfortunately, all too common on the CJAA engines.