Lower Engine Tapping/Knock Sound (1 Viewer)

[kevinkevinkevin]

Hey, y'all

1994 here. I've read maybe 50 threads about this issue. Took it to a mechanic (who, admittedly, specializes in old Volvo's) and he says that it may be a connecting rod, but almost impossible to tell unless we take the engine apart (understandable). He also mentions that he's seen people drive with it for years before having to rebuild the engine. The knock/tap doesn't go away and goes up with RPM. Can even hear it faintly at highway speeds.

I feel like all of the threads on these issues haven't really been resolved. Maybe the reason is because it could very well be a thousand different reasons for the noise, but I figured I'd start a newer thread to see what other people have done to figure this issue out.

My thoughts:​

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1. I feel like it's not a rod because it's not *that* loud. I know rod knock is pretty loud.​

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2. Worst comes to worst, I have to rebuild the bottom. I feel like it'd be silly not to do it sooner rather than later because it could potentially cause more problems. Anyone decide to live with the issue and later realize it caused some more problems down the line?​

Here's a video of the noise.

 

[voodu3]

Check your power steering pump. @slow95z told me that a bad pump can be misdiagnosed as a rod knock.

 

[kevinkevinkevin]

Check your power steering pump. @slow95z told me that a bad pump can be misdiagnosed as a rod knock.

Will for sure check that! Have read that, also. But the mechanic mentioned they hear it coming from the engine block -- whether or not it's coming from the top or bottom, we'll have to get a stethoscope. When I open up the hood, the sound doesn't seem to be coming from the PS pump. Do you think the sound could reverberate into the block??

 

[slow95z]

Well since its bolted to the block yeah. just take the 2 bolts out and slide it off. its going to spray oil but you can crank it for 10 seconds to see if it goes away.

 

[lp2k]

Here is a silly question. are you having to add power steering fluid almost all of the time? Bad/Hard steering? it will be cheaper to try and repair/replace the power steering pump vs doing the engine rebuild.

 

[kevinkevinkevin]

Here is a silly question. are you having to add power steering fluid almost all of the time? Bad/Hard steering? it will be cheaper to try and repair/replace the power steering pump vs doing the engine rebuild.

Nope! When I bought the truck, I noticed it leaking from the cap, but it ended up being the PO overfilled it. I haven't noticed any major fluid leaks after making sure the level was proper. The steering is a *little* hard, but not that much harder than other 80's I've driven. I'll talk with the shop owner today and see if he can look at the PS situation and report back!

 

[BILT4ME]

Nope! When I bought the truck, I noticed it leaking from the cap, but it ended up being the PO overfilled it. I haven't noticed any major fluid leaks after making sure the level was proper. The steering is a *little* hard, but not that much harder than other 80's I've driven. I'll talk with the shop owner today and see if he can look at the PS situation and report back!

If you have any records or information from the PO the the PS pump was recently repaired or replaced, that would go a long ways in your proper diagnosis of the noise.

Otherwise, do as @slow95z stated and pull the pump to see if the noise stops.