GenVibe - Community for Pontiac Vibe Enthusiasts

My son's 2003 Vibe has a loud knocking noise, with 123,000 miles (1.8 Liter, Vin 8, FWD, manual trans). Engine otherwise runs OK but sounds like a rod is about to come through the engine. Video attached. There was a main seal leak and the car was run low on oil and later overfilled (son now understands how to check and fill). Reading other posts it sounds like it may be a bad bearing caused low oil or high oil. I pulled the valve cover and see no obvious issues yet, and all lifter springs seem to be OK (tapped each with wood dowel and hammer) I plan to pull the oil pan and inspect a few bearings. Can anyone identify the sound as most likely from the bearings? Can anything else cause this noise?It likely the bearings are scored but crank surface is still good (I never win the lottery)?Is it worth the trouble to evaluate further, or am I better off to buy a used engine for $1300 and put it in?I have an engine hoist but not a vehicle hoist...Can I get the engine out from the top if I disconnect the manual transmission and clutch first, or does the engine have to slide out under per repair manual?Thanks!!

Attached files Vibe_knocking_low.wmv (803.8 KB) 

Sorry to hear about the engine. If you can get a different engine with low miles for that price, I would just go for it. Looks like an Envy colour Vibe... Very rare...

Last time I heard something like that was in an 87 pony. 1/4 of a piston was laying in the bottom of the oil pan. Take the engine and tranny out together. Might have to remove a few parts to get it out!

I'd start with dropping the pan and checking the rod nearings. That's a low cost thing to try first, before going after a whole engine.I replaced the rod bearings in mine. You can drop the pan easily enough with the engine in the car. Don't buy a pan gasket, just use rtv to seal it when you put it back on. The rod bearings were abut $25 if you need them. Pull the spark plugs to make it easier to turn the engine by hand to access the rod caps My 1&4 hearings were awful but the crank was fine.

Hard to tell from the video but the tapping noise sounds too fast/rapid for a bottom end knock, unless the engine is idling fast. Sure it's not coming from the top? That engine has a mechanical valve train and uses shims to adjust valve clearance. Good luck....keep us posted.

Not sure what else up top to check...I checked gap from each cam shaft lobe to valve lifter - all the intake valves are less than .009 inch (smallest feeler gage I have) and most exhaust lifters have more gap - .010 to .011 gap. Cam surfaces show some wear but not bad. I am not sure but don't think this is enough gap to cause that much noise. When I tapped down each individual lifter to check springs, the rebound sound is quieter but similar to my problem sound. I also thought we found the problem when we saw a sheet metal plate showed marks of hitting a cam, but I bent it back in shape and that was not the issue. It appears an oil spout was pushed a little hard into the oil fill hole, which bent a thin sheet metal plate insdie the cover, such that it hits a sensor bump on the intake cam shaft. It appears the cam just cuts the cover and bends it out of the way, but no lingering damage.Next step is to drop the oil pan.

Thanks all for your input. I dropped the oil pan and rod bearing cap 1 (nearest oil pump) and 4 (farthest from pump). Bearing 4 shows signs of major oil starvation, and the cap and crankshaft have some scratches but not deep. Rod 1 has a hammered and deformed end flange on bearings and heavy scratches; crankshaft has heavy scrathces, bearing cap some (see picture), I presume the crankshaft is toast, and may cost more to machine and or replace than a used engine ($1300). Need to pull the engine in any case.Before I buy the engine, any other options that would make sense?

Attached files 2003Vibebearings.pdf (221.2 KB) 

Mine did that...... I found a great fix though..... traded for my Camaro. LOL. I found a dealership that offered me what I owed on the Vibe, and they had a Camaro sitting there, and I said.... Well.... it's at least still a GM.As long as the body is in good shape they are worth the new engine. They are great cars, and great to drive. I hope you get it fixed, and keep oil in it.

Quote, originally posted by grm »Before I buy the engine, any other options that would make sense?One might consider just replacing rod bearings and see how long the new set lasts (although that #4 is a hassle with the engine in the car, but it can be done). You could do that a couple dozen times before it costs more than a new engine. That is pretty much what I am doing with mine. The bearings were pretty bad, but the crank and caps looked fine. If mine go out again, I'll have decide to repair or replace the whole car. If you are still living with the main seal leak that caused the problem in the first place, then maybe a replacement or more involved rebuild is better. Especially if you plan to keep the car for a long time. If you get a used engine, make sure it comes with a warranty.