Engine rattle investigation (1 Viewer)

[clx16]

One angle I didn't include.

 

[clx16]

Amazing, this is GOLD. Thank you for posting this @clx16. I was investigating this exact same noise yesterday morning; that kind of irregular, clackety rattle when the engine was cold. Using my stethoscope I was hearing the noise loudest on the timing cover just above the timing marks; I'm sure if moved a little to the right (at the top of the oil pump cover) it would be even louder. You've saved me a lot of time here. Thank you!

Any chance you've been able to put the stethoscope on the oil pump cover and confirm your suspicions? Just wondering how stupid I was for not getting even that narrowed down with the stethoscope when I was failing to hear it.

 

[SteveH]

@clx16 - I just bought a '93 LC with 395K from a buddy and much of the time (when started) it knocks like the video in your original post - just a faint 'tap' every now and then of something loose. About 1 time in 10 that you start it, it clatters with an ungodly death rattle - a continuous clatter that makes your blood run cold. It's not rod or main knock, and oil pressure is good. It's not an accessory drive noise, AFAIK.

It hasn't done this death rattle for long, and I drove it home (5 miles) to my house this way, and it quieted down eventually during the drive. Your post here is the only one that gives me an idea of where to start with a stethoscope. I now turn on my phone video every time I start the truck, hoping to catch this continuous clatter.

I will update this thread as I go, and my first step (after a serious power washing) is to pull the valve cover and look down at the timing chain guides and see if they are part/all of the issue. After that, I'll put a stethoscope on the oil pump (if i can get to it) and see if that is the source of the clatter.

 

[clx16]

@clx16 - I just bought a '93 LC with 395K from a buddy and much of the time (when started) it knocks like the video in your original post - just a faint 'tap' every now and then of something loose. About 1 time in 10 that you start it, it clatters with an ungodly death rattle - a continuous clatter that makes your blood run cold. It's not rod or main knock, and oil pressure is good. It's not an accessory drive noise, AFAIK.

It hasn't done this death rattle for long, and I drove it home (5 miles) to my house this way, and it quieted down eventually during the drive. Your post here is the only one that gives me an idea of where to start with a stethoscope. I now turn on my phone video every time I start the truck, hoping to catch this continuous clatter.

I will update this thread as I go, and my first step (after a serious power washing) is to pull the valve cover and look down at the timing chain guides and see if they are part/all of the issue. After that, I'll put a stethoscope on the oil pump (if i can get to it) and see if that is the source of the clatter.

If it does seem to come from the oil pump. I recommend you replace the impeller as well as the cover and 0-ring at the same time. Not expensive if you are ordering from partsouq and you likely have to fix that leak anyway on the front. You'll have to crank pulley off so order the front crank seal too.

 

[SteveH]

Sounds like good advice - I expect to see wear just about everywhere I look.

I have a '57 Ford project to finish up and a '97 Jeep Chimporee to sell, and then the '93 will be queued up. I'm excited to have a starting point (the oil pump with a stethoscope), which I didn't have up to now. I will reply back to this thread.

 

[SteveH]

Some promised follow-up:

The alternator bearings were shot on this truck and made a horrid racket (louder than all other engine sounds) ever since I bought it. Since I replaced the alternator with OEM reman, the engine is nearly silent, I have started the truck perhaps 40-50 times, and it's silent at startup, as well. I also changed the oil and used a thinner oil (10w-30 synth) vs. what was in there, but I used a genuine Toyota filter.

I also replaced the valve cover gasket and the timing chain was tight and guides showed moderate wear. Cams look like new, and cylinder bores were great. So, I don't see any smoking guns in the engine. Pix here: Build: Another green 80 - https://forum.ih8mud.com/threads/build-another-green-80.1341738/

So, I have never heard this clatter again, or any typical 'oil hasn't quite hit the bearings yet' sound. I don't know what my clatter was, but it seems gone. I will update this thread if not.