I have a 1985 Cavalier that I've owned for about a year. Without tearing the transmission out, I've been trying to hunt down a knocking noise.
Its not there at startup but starts after 10-15 seconds. Its noisier in park and neutral. It drive, it never gets noisier though its speed increases with engine RPM.
Have already replaced main and rod bearing. No change. I tried unplugging spark plugs and running it but there was no change after disconnecting one at a time.
With a hose, the noise seems to come from the lower oil pan or between the engine and transmission. I'm guessing its wrist pin for the 1st drivers side cylinder, crankshaft bearing at end of block (not a main/rod) or a cracked flex plate.
The car drives normally other than some heavy clunking shifting gears that I've attributed to work mounts.
I apologize for all the leaks, etc. No point in fixing until I can diagnose this issue. I am not currently driving it.
I do need to note it drove 100 miles to my house after I bought it (told original owners if it'd make it, I'd buy it) with the noise. No change.
https://youtu.be/ZVscFoDcGak
1985 Chevrolet Cavalier Sedan
2.0L I4 TBI OHV
Sounds like noisy lifters to me
Pretty common issue on these engines
I have a similar noise (not as loud)
It’s worse when it is cold outside.
You can try to adjust the valves or put some miracle in a bottle in, but ultimately, the only real way to fix this is to change the lifters...
~ Mike ~
Do you mean the lifters on the back side of the motor? I haven't considered that. Unfortunately hydraulic lifters I'm not too knowledgeable on. Never had to mess with them on my other cars. Will definitely read up on it tonight!
1985 Chevrolet Cavalier Sedan
2.0L I4 TBI OHV
You may be right...
... skipping in my video to this:
https://youtu.be/ZVscFoDcGak?t=45s
... sounds just like this one...
https://youtu.be/28IRZ9l2MCE?t=36s
Obviously that's a different engine... but the rhythm/tap is almost spot on and they claim lifter noise as well.
In all honesty, I was prepared to drop another motor in it but had problems actually finding a decent one. A cylinder head would be much easier to source...
1985 Chevrolet Cavalier Sedan
2.0L I4 TBI OHV
I had a reply to the YouTube video suspecting the flex plate. It is loudest at the inspection cover but I couldn't find any loose bolts, cracks, etc. when I inspected it with a USB camera.
I know sound can travel throughout an engine and felt maybe I was just being delusional; wanting the cheaper solution to the problem.
For now, my mechanic is getting a quote for a rebuild. If they find a cracked flex plate while its being pulled, they'll stop there.
I'll certainly update this if I figure out the cause of the noise. Hopefully save someone else the trouble.
1985 Chevrolet Cavalier Sedan
2.0L I4 TBI OHV
I would check the dipstick tube to make sure it is not hitting the crank. Had this happen a few times. Also check the torque converter bolts. Since it's a gm you can actually unbolt the torque converter and eliminate any flex plate/ torque converter/ trans noise.
On the inside my car looks like a fighter jet.
I never thought of that (dipstick tube). The only thing that may have disproved that was that the noise would change between park and drive (quieter in drive). Unfortunately, there's not much else to diagnose.
The shop narrowed down the noise to something internal on the driver's side most piston.
The shop did get it out and set it down for me to look at. The flex plate (unfortunately) is solid. No bolts were backed out, etc.
However, in addition to the engine noise, after I took the torque converter off, I noticed some substantial cracks on the interior of the bell housing of the transmission. I'm talking right where the shaft comes out. The depth of the cracks split about 2/16"-3/16".
Upon seeing that, I knew even if I got the engine fixed, it wouldn't be too long til the transmission either broke apart of started to hemorrhage fluid.
So I ordered a replacement (used) engine and transmission from LKQ ($900 total). They've only got 59K miles on them and its warrantied for a period of time. The pictures of the donor vehicle were immaculate (a bright blue hatchback). If it were 159K, I'd expect rust on the body, etc.
Here's a pic of the donor vehicle:
https://www.lkqonline.com/images/salvage/X/vehicles/$D1/22/$D12218-130_0_fmt.jpg
Thank you everyone for the help on trying to diagnose it.
I would've loved for it to be any of those easier things. Still, one less Cavalier getting crushed for now at least.
1985 Chevrolet Cavalier Sedan
2.0L I4 TBI OHV
Don't assume mileage means rust. I've got a 94 with 85,xxx, a 92 with 145,xxx and an 88 with 202,xxx and neither of them has any rust, except for the heater blower boxes. Seriously, all 3 rust free.
Hopefully the engine/trans really does only have 59K on them. You should be good for many years of dependable service from them. I would suggest you put new gaskets and seals on them though. Age alone would warrant that. And of course, it is much easier to do before you put them in the car.
Good luck
John Brown wrote:I never thought of that (dipstick tube). The only thing that may have disproved that was that the noise would change between park and drive (quieter in drive). Unfortunately, there's not much else to diagnose. .
That does not disprove it, that would make it more plausible since the dipstick is probably in the front, in drive the engine will want to rock backwards away from the radiator support.
On the inside my car looks like a fighter jet.
No harm in checking, we still have the motor so I can have the shop check it. I'll let you know what they find.
1985 Chevrolet Cavalier Sedan
2.0L I4 TBI OHV
