Question : Low rumble/vibration at idle

[primesuspect]

I am getting a low vibration at idle. It disappears as soon as i'm on the throttle. any ideas. I am going to do some more troubleshooting in the morning to see if it is motor mount. it oddly coincides with my SES light going off...all on it's own after a seafoam treatment. I wonder if my belt tensioner may also be contributing to the vibe. I cant wait to get to wrenchin in the snow....Cheers!

[60dgrzbelow0]

Is it cold enough up where you live right now to require one of these?

http://cgi.ebay.com/ebaymotors/GM-BLOCK-HEATER-FOR-3-1L-3-4L-V-6-ENGINE_W0QQcmdZViewItemQQhashZitem22eeb67ac0QQitemZ150033824448QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

[60dgrzbelow0]

I am getting a low vibration at idle. It disappears as soon as I'm on the throttle. any ideas. I am going to do some more troubleshooting in the morning to see if it is motor mount. it oddly coincides with my SES light going off...all on it's own after a seafoam treatment. I wonder if my belt tensioner may also be contributing to the vibe. I cant wait to get to wrenchin in the snow....Cheers!

What did you know about the SES issues B4 your SeaFoamed the engine? Can you run scanner and list any codes the engine is throwing? Could be anything from a Bad Main Bearing to a separated Harmonic Balancer Elastomer Seal to a Bad Torque Converter...and so forth. Have you noted any other symptoms that might give some direction?

[primesuspect]

Not really that cold...yet. i have a cord run out to my parking spot though, in preparation for the chill.
I dont have a scanner yet. I plan to get one after the holidays cuz $$ is tight. So I dont know what codes have popped up. I thought it may be low trans fluid but thats not it. My belt tensioner is wobblin like a mother, so i am gonna swap it out and see if that makes a difference. Elastomer seal on the balancer eh? Would I see any oil leakage in the are? The vibe is not real bad, but it is present and annoying. Doesn't seem to change when i cycle through drive-N- to reverse. not really any other symptoms. at 325000km's I am praying to avoid a catastrophic failure.

[60dgrzbelow0]

You might lend an ear toward a listen at the Timing Cover area of the engine at idle to hear the clinks and chinking noises that a seriously worn out timing set will make in its "Elder Years". You don't say enough about your car's engine for specs and other particulars...but invariably in high-mileage motors...the Timing Chain, Camshaft and Crankshaft Sprockets get God-awful wear... They stretch and wear into one another in such an extreme manner that frequently...when the engine idles...the slack side of the chain in front of the pulling direction of rotation... will rattle around to the point of even clanging at times upon the Timing Chain Cover...the "Bruxism" of the Chain Plate segments chew well and truly into the gears and everything can loosen up sufficiently to "Jump Timing". If that happens...the valves will open or close at the wrong times and meet the tops of the pistons...with catastrophic results to the health of "The Old Girl".

Changing the Timing Set out requires some skill, patience...good attention to details and about three specialty tools to get the job done. If this turns out to be the case... I'll provide you with links to the information you need and the images from my Photo bucket make for a good visual reference on how to do this repair. This is not the kind of thing one should do in the out-of-doors while up in "The Great White North". Cast Iron and steel expand or shrink at the rate of 1/64 Millionths of an Inch for every single Degree Fahrenheit either up or down on the Thermometer Scale and these metals can become extremely brittle and easily fracture in deep cold. So if you have a friend with a heated garage; hopefully one who is not a "Scrooge"...perhaps you can winkle a spot in there to do any necessary Emergency Cold Weather Repairs.

[60dgrzbelow0]

Not really that cold...yet. i have a cord run out to my parking spot though, in preparation for the chill.
I dont have a scanner yet. I plan to get one after the holidays cuz $$ is tight. So I dont know what codes have popped up. I thought it may be low trans fluid but thats not it. My belt tensioner is wobblin like a mother, so i am gonna swap it out and see if that makes a difference. Elastomer seal on the balancer eh? Would I see any oil leakage in the are? The vibe is not real bad, but it is present and annoying. Doesn't seem to change when i cycle through drive-N- to reverse. not really any other symptoms. at 325000km's I am praying to avoid a catastrophic failure.

The Harmonic Balancer is connected to the Crankshaft via a notched end that serves to key up with a rectangular Woodruff Key and on its way over the the nose of the crank...its outer race slips into the Timing Cover Case ...mating up on the outside with spring supported PTFE Oil Seal. The HB is composed of two thick and sturdy masses of steel that are tucked on inside the other and held together in between by a durable Elastomer Glue.

The action of the HB is to dampen the heavy longitudinal vibrations imparted on the crankshaft by the pounding forces of the pistons transmitting the rotational energy to the crankshaft via six, forged connecting rods. In rare cases...the Elastomer can let go and become quite loose and shake the car like a Chihuahua Shitting a Peach Pit. The outer race of the HB will not hold its original factory timing position if this happens and the weighty, massive metal race will either advance or retard as it slips and slides back and forth over the inner portion.

The way to diagnose that the HB has failed is to draw an indelible white mark in a straight line that runs from the center of the HB, out across both segments ...right up to the very edge of the outer race. If the engine RPM is cycled up and down...and after shutting down the motor...this line looks broken up into two separated lines between the two halves of the HB...you will need to replace the TC Seal and get a replacement HB before the outer race flies of in an at speed condition and kills anyone. If this happens at higher RPM... The dynamic vibrations from the rotating crankshaft can harmonically increase in amplitude to the point of literally shaking the engine to pieces...and make one Hell of a mess out of your motor!