What the heck! The Death Rattle?

Post by **holler1** » 07 Nov 2011, 17:24

The only suggestion I can make it is to get a good mechanic to check it. To me, definitely a non-expert in engine noises, it doesn't sound like a valve noise, but something deeper in the engine. The suggestion made earlier to try to localize the noise seems like a good one.

andy86+volvo · Post by **andy86+volvo** » 07 Nov 2011, 17:34

Thanks for the reply

Post by **renns** » 07 Nov 2011, 19:16

Check the easy stuff first. Is oil level up to the top line on the dipstick? With the engine idling, pull the oil filler cap, and check to verify that you see lots of clean oil circulating. If the oil is foamy in appearance, or lacking in volume, it may indicate problems with oil delivery to the top end. If you have a local buddy with the same car, a side-by-side comparison of oil movement under the filler cap might be helpful.

Are you sure the car is low on power, or is it possible it's just your concern over the noise that's giving that impression? The reason I ask, is that I had a noise like that in my old 850 that appeared after trying the "Seafoam" trick (avoid at all costs IMO). I tried sump o-rings, oil flush, switching to different oil types and weights, and nothing ever got rid of that noise. I drove the car many 10's of 1000's of miles in that condition, before selling it off to someone else who may still be driving it.

Post by **renns** » 07 Nov 2011, 19:27

holler1 wrote:The only suggestion I can make it is to get a good mechanic to check it. To me, definitely a non-expert in engine noises, it doesn't sound like a valve noise, but something deeper in the engine. The suggestion made earlier to try to localize the noise seems like a good one.

Holler,

Your comment got me thinking. Bottom end noise (piston, rod, etc) should make a sound with every revolution, whereas valvetrain noise should occur once every two revs due to fact the cams spin at half crank speed. To check frequency of clicking, I played the youtube clip along with an on-line metronome, and found a match at about 460 beats per minute. If my thinking is correct, this seems to indicate valvetrain noise rather than bottom end noise. Andy - you may want to do a compression check shortly as well to assist in the diagnosis. If it's a stuck valve, compression will be low on one cylinder, but I would think it would run rougher at idle than yours seems to. If it's merely a stuck lifter, compression should be fine, and you may as well keep on driving.

Here's that on-line metronome link - ah the amazing internet. We sure owe Al Gore big-time for inventing it

http://advanced.bestmetronome.com/
Delete all sounds at top, add metronome tick, select beats per minute, and hit play. Adjust BPM to match the tick in the youtube clip...

Post by **JimBee** » 08 Nov 2011, 05:21

Renns: using the metronome to quantify bpm and relate that to upper vs lower rev's was some scholarly diagnosis

I'm curious why you avoid the Seafoam trick.

Post by **holler1** » 08 Nov 2011, 06:23

renns wrote:
holler1 wrote:The only suggestion I can make it is to get a good mechanic to check it. To me, definitely a non-expert in engine noises, it doesn't sound like a valve noise, but something deeper in the engine. The suggestion made earlier to try to localize the noise seems like a good one.
Holler,

Your comment got me thinking. Bottom end noise (piston, rod, etc) should make a sound with every revolution, whereas valvetrain noise should occur once every two revs due to fact the cams spin at half crank speed. To check frequency of clicking, I played the youtube clip along with an on-line metronome, and found a match at about 460 beats per minute. If my thinking is correct, this seems to indicate valvetrain noise rather than bottom end noise. Andy - you may want to do a compression check shortly as well to assist in the diagnosis. If it's a stuck valve, compression will be low on one cylinder, but I would think it would run rougher at idle than yours seems to. If it's merely a stuck lifter, compression should be fine, and you may as well keep on driving.

Here's that on-line metronome link - ah the amazing internet. We sure owe Al Gore big-time for inventing it
http://advanced.bestmetronome.com/
Delete all sounds at top, add metronome tick, select beats per minute, and hit play. Adjust BPM to match the tick in the youtube clip...

Renns,
Wow! As Myron Cope (I'm a Steelers fan) used to say "double wow!". I was thinking rods or bearings. I had a Sunbeam Alpine a long time ago that sounded a little like that - had a bad bearing that I had to sand down occasionally. I was listening to it too and thinking - if only I could estimate the frequency, it might tell me something. The closest I got was to estimate it was clanking around 4-8 times per second, which would be 240-480/min. You did it right.

Post by **renns** » 08 Nov 2011, 08:50

JimBee wrote:Renns: using the metronome to quantify bpm and relate that to upper vs lower rev's was some scholarly diagnosis
I'm curious why you avoid the Seafoam trick.

The top-end knock in my car appeared immediately on startup after the Seafoam process, and stayed afterwards no matter what fix I tried. In my view sucking snake oil into the intake is of questionable value to begin with, and I should have known better. Some others love the stuff though, so to each his own. Here's a thread warning of the risks of Seafoam: https://www.matthewsvolvosite.com/forums/viewtopic.php?f=1&t=13217

andy86+volvo · Post by **andy86+volvo** » 09 Nov 2011, 20:00

Dude, that is freakin brilliant! Wow I would have never have thought of that it makes perfect sense but I would have never put two and two together. Thanks alot I allready wanted to do the compression check but dont have the tester. Does anyone have any idea how much one of those things run? Since I just got the sump rings in the mail I am gonna go ahead and do it if I can get a loaner compression tester from someone and find promising results. But I will deffinetly post the results thanks for your great thoughts and thank you Al Gore!

andy86+volvo · Post by **andy86+volvo** » 10 Nov 2011, 17:57

I think I'm with you on the seafoam Renns. I had done the seafoam in the crankcase and intake treatment not even 3 days previous to the initial video posting. It may be a coincidence but I will be verry reluctant to pick up that can again next time im at the parts store. EVER!

Post by **renns** » 10 Nov 2011, 18:49

If the compression test turns out OK, I'd be inclined to just keep driving the car as-is. I drove mine daily for a year and a half with the ticking lifter, and it never caused a problem other than irritation. Strange coincidence about the Seafoam treatment...

What the heck! The Death Rattle?

Re: What the heck! The Death Rattle?