Lost compression, R&R timing chain in-car?
 

Hello,

My 2012 2.4L Tucson GLS has 85K miles and has been pretty much problem free. Then one morning I try to start it and it spun over with little resistance and not even as pop. Did some diagnostics and only 15 ps compression. No odd noises, had been running fine, etc. So what? Sheared key, failed guide or tensioner & skipped chain, broken chain?

Is this an interference engine?
Can I R&R the timing chain with the engine in the car?

Can't find much Tucson repair info online. Any help greatly appreciated.

Thank you. Kent

As far as I know, all Hyundai engines are interference engines
Meaning that when timing belt or chain breaks, the valves and pistons collide and lots of stuff gets messed up

You can not just replace the chain or belt without inspecting the inside of the engine to find out what is broken.
Sorry for your loss.

I would go get an estimate to see what it cost to fix
And ask about just replacing the engine .. cost

Good luck

Thanks Avisitor,

I'll be doing the work myself. Depending on what I find when I dig in today I'm fairly certain I'll end up pulling the head along with the timing chain cover. I'm hoping it isn't a catastrophic failure and just a few bent valves. I can lap in a few new valves but if it's too bad I'll get a reman head (any recommendations or warnings?). I just hope it hasn't severely damaged any of the pistons as then it becomes a completely different challenge.

Thanks again, Kwall

You are a better mechanic than me.
If you are doing the work yourself then would do a thorough inspection
There has to be a reason for the timing chain (if it is a timing chain) to break or skip or whatever
And with that, maybe little pieces everywhere .. sump, pump??
Want to make sure after you fix one problem that there isn't another waiting to happen.

Good luck

Would be very interested in updates on your progress

Hi Avisitor,

Well, it appears to be just a stretched chain that skipped. None of the guides are broken, tensioner appears fully (?) extended yet I have way too much slack in the chain. Left it there for the day. I'll pull the tensioner and guides over the coming days and insoect for wear, etc.. Also will pull the cams & pressurize the cylinders to see if (little doubt though...) its blowing past the valves. Thank you for your interest.

Kent

That sounds like you got lucky
And all you have to do is to put it back in time and put a new chain on
And hope for the best.

Let us know if it works.
Fingers crossed.