1.9L bottom end noise
 

New here, 2001 sedan with 100k miles on the 1.9L DOHC. Got a knocking noise and I'm pretty sure its in the bottom end. Pulled the valve cover, everything up top looks good. Next step, drain/pull the oil pan and see whats in there. Anyone ever done any bottom end work on the 1.9L? How difficult are these to work on? I'm fairly mechanically inclined, but I'm not sure, if it needs bottom end work, what I'm getting myself in to. Car was an old lady's and is still an 8/10. Would like to keep it going. Thanks in advance

Note; I did have a slight loss of power that seems similar to when you "spin a bearing". If I have to replace main or rod bearings, again is it difficult, or expensive if I have to take it in?

These engines only tend to self destruct due to oil starvation issues. If the oil was run down low enough enough times or exceptionally low one time, chances are you will want to do more than bottom end work if you want a non oil-burning ride.

Oil control rings and valve guide seals let the oil into the cylinders. If you take it apart, at least do the oil control rings.

What was the compression before you disassembled? That is a strong indication of whether you can get away with just doing the bearings or if it makes more sense to do a complete overhaul

If it has any damage to any bearings it will need major work. The crank has to be perfect to work correctly, if you find a scarred bearing just pull the engine.

I did not check compression before hand.

"Major Work" Can you elaborate a little for me please? In regards to the crankshaft, can you refurbish those, or am I looking at just replacing it?

If you have damaged the crankshaft a full service machine shop can have it repaired. If the main bearings have spun in the block the block will need to be line honed. If the rod bearings have spun and rods are not destroyed they can be resized also. It all depends on how much damage is done and what has failed. Usually bearing problems are caused by running an engine out of oil. You will need some professional help if the engine is really damaged. You may need to start with another engine. No way of knowing without investigation on your engine.

​​​​oil starvation not only leads to spun bearings in these S cars. There are a host of other repercussions with this engine that usually make it cost ineffective to tear down and rebuild a Saturn DOHC that's been run low on oil.

Well, pulled the pan, and sure enough, spun a rod bearing. Only one was bad, however, I replaced all of them. Buttoned it all up, fired it up and it ran nice and smooth. Took it out for about a 5 mile drive and everything ran perfect. Got in it this morning and the knock came back. Not as bad, but def came back. Not sure what to think now.

Reread post number 7, you are wasting money by not listening.