My 1990 w/66kmi started emitting a loud tappet noise, but the other day the sound seemed to come "a little further down" in the block. I brought it home and it's on my lift. The valve train on the front head seems fine and the plugs are normal. The engine pan looks like a typical PIA, the starter, shields, and general camaouflage stuff. Do you think upon removing the pan and pulling end caps, that I'll find anything? This noise is definately from the engine, but maybe I'm overlooking anything that might be common to these cars. This is a great car, but.....Thanks in advance for any help, Rob If it's a motor job I may keep or maybe sell :cry:
Does the noise only happen when cold/hot? What about idle/throttle? What happens to the noise when you accelerate and then go back to idle?
Taking that pan off is a pain, so I'd drain the oil and look for metal particles. Maybe send it in to get analysed to see what materials are in the oil (only costs like $20)...that will tell you if there is large amounts of bearing material there--sign of rod knock or something else needing engine rebuild.
What about lifter knock? Could be that too, and the lifters cost like $10 for a set of 8 from GM brand new.
Jason
Thanks for the reply The noise appears after starting and also upon revving . It does sound like a collapsed lifter and it seems like it is right under the top plenum. So I guess I have to pull that to gain access to the lifters. Maybe a compression check would confirm this too? Gee this will be fun. Thanks
Ok...everyone bow their heads and pray that Rob has only got a collapsed lifter!!! 8)
Good Luck man!!!!
Question, Does it have a miss? Reason why I am asking is because if the lifter is collapsed, broken valve spring, or bent push rod. The performance tuning of the engine is going to change. for most bearing knocks you get noise (loudness depending on the condition that it is in. Hope fully this helps in figuring it out. :)
Hi Gang I'll test for compression and look for any weird patterns when doing so and hopefully have an answer by the weekend. There is a good chance I may sell. I have pics also. This is a nice car Red, tan leather, sunroof, 66k mi, all books, etc.
loose torque converter bolts, or in my case, a cracked flywheel
makes a nasty noise that is hard to pinpoint. My flywheel was
cracked in a complete circle around crankshaft bolts. Try checking
bolts to torque conveter and look real hard toward middle of flexplate.
Ahhhh Another possible source!.. Had this problem on my Suburban years ago, and will an aluminum block this noise conducts well. I'll put it on my lift and inspect thoroughly. Thanks again! Rob PS The motor idles and runs well. If one cylinder was off in a 6 cylinder motor you would certainly notice a decrease in performance. IF this is the source of the noise, how did you replace the flywheel, or is it a flex plate? What did you remove? Thanks in advance. Rob
I have the flex-plate left over from the 5-speed conversion. If you find it is your flex-plate you can have mine... 8)
replacing flex plate was beyond me, engine craddle needed, turbo removed and tranny pulled away from engine, the replacement one from GM was beefier than my original.