LX9 NOISE 120 thousand miles uplander van. 2006

[rick444]

Tappet tick and maybe more. No history bought used.

Runs quiet for 30 sec then ticks. Shorting cylinders loaded and unloaded does not make rod knocks.
Thick 20W50 not much help. Full power and good idle.
No warning lite but I need to do pressure check to be sure of oil status.
Somebody says oil pump is weak causing oil starvation to lifters; maybe too much bearing clearance. Maybe clogged gallery.
I bought a low mileage replacement engine rather than experiment with oil pan removal.
Nonetheless, any theory from friends?

[neophile_17]

Before pulling the engine go back to 5W30. If the lifter tolerances are still tight enough then the thicker oil could be causing the problem you're trying to prevent. You might also try some marvel mystery oil. I've seen it help with finicky lifters and it's cheap to try. Either way good luck!

[rick444]

Thin oil for ticking LX9

Before pulling the engine go back to 5W30. If the lifter tolerances are still tight enough then the thicker oil could be causing the problem you're trying to prevent. You might also try some marvel mystery oil. I've seen it help with finicky lifters and it's cheap to try. Either way good luck!

I was thinking about that too. Maybe I went the wrong way using 20W50.
I had 10W30 at first and no change. I will come back on the subject aft I give the new oils a chance.
Thanks. PS Oil pan is a real pain to pull on the Uplander!!

[rick444]

Further to this:

Tappet tick and maybe more. No history bought used.

Runs quiet for 30 sec then ticks. Shorting cylinders loaded and unloaded does not make rod knocks.
Thick 20W50 not much help. Full power and good idle.
No warning lite but I need to do pressure check to be sure of oil status.
Somebody says oil pump is weak causing oil starvation to lifters; maybe too much bearing clearance. Maybe clogged gallery.
I bought a low mileage replacement engine rather than experiment with oil pan removal.
Nonetheless, any theory from friends?

Could I bypass filter for a test to see if more flow stops the noise? How to do? I hear there is a spring loaded bypass plug or something like that, externally acessable I hope.
I need to make a flow experiment before I condemn the engine.

[Guest]

The bypass plus is only there to allow oil to flow to the engine is the case that the filter gets so plugged that oil will not flow through it. It is not an externally accessible item, well, not easily. It is located behind the oil filter adapter housing.

If you're thinking that the oil filter might be a restriction, change it, don't bypass it.

[rick444]

Tappet tick and maybe more. No history bought used.

Runs quiet for 30 sec then ticks. Shorting cylinders loaded and unloaded does not make rod knocks.
Thick 20W50 not much help. Full power and good idle.
No warning lite but I need to do pressure check to be sure of oil status.
Somebody says oil pump is weak causing oil starvation to lifters; maybe too much bearing clearance. Maybe clogged gallery.
I bought a low mileage replacement engine rather than experiment with oil pan removal.
Nonetheless, any theory from friends?

After driving on road I notice the tick is affected by very light load "tip-in", whereas it gets quiet around 1100 rpm. Either side of 1100 rpm "tip-in makes tappet-like noise. Now, I must admit, that it is NOT tappets. I think piston noise, with one being especially noisy.
I plan to scrap the engine. RIP tired engine. Thanks Guys!

[rick444]

Priming of oil gallery

After driving on road I notice the tick is affected by very light load "tip-in", whereas it gets quiet around 1100 rpm. Either side of 1100 rpm "tip-in makes tappet-like noise. Now, I must admit, that it is NOT tappets. I think piston noise, with one being especially noisy.
I plan to scrap the engine. RIP tired engine. Thanks Guys!

The distributorless engine has no distrib, Yet is it still possible to engage with the oil pump and spin it like engines of 30 years ago? I'd like a full pressure prime rather than just filling galleries.
How does that work?

[rick444]

Sounds like these engines use the old gear driven distributor setup as yesteryear except minus the upper end of the old unneeded full distributor head. Noweights or springs;just a oring sealed cover and geared 8mm male hex-end shaft where the large distrib used to be. Now the people familiar with the setup call the new arrangement of gm the: "DIZZY PLUG" I suspect that is to mean a nickname for "DISTRIBUTOR PLUG" to equal "DIZZYPLUG". Cool.
The engine thinks it is driving the full distributor/oil pump gear except now is simply turning the oilpump via that same gear off the camshaft gear mate. Friends warn to watch for a messy leaky oring, and try to replace it with best quality since it can be a leak source of the DIZZY.
The way I understand is that the dizzy w/o the crankshaft pumps to the galleries,but some reservation of getting oil to the lifters because of some rotational feed holes indexing (multiplexing that would require full rotation of crank and cam to get full oil feed to valve train. Dont know bout that part though. Like a spit hole rotary valve that shares oil feed with a shaft that has to turn to send oil to lifters via some shaft hole somewheres.. Really?

[rick444]

Pulled pan, old engine had spun bearings on 3rd and 5th cylinders. I do not know history from previous owner except claim that it made noise right after quick oil change. And now, after purchase they will not answer any calls. I get it.
Sounds like a guilty-ness.
I suppose they let it run low on oil then tried to fix it with an oil change. It was very clean inside, and ran good. Really it sounded like tappets, and did not reveal itself with shorting plugs. I got a new engine in it now that is good.
Sooo, that was fun.

[rick444]

Follow up:
I changed the engine because it is so much work to pull the pan to get a look at the old engine. The old engine upon autopsy shows spun bearings on #3 and #5 cylinders.
So, in conclusion I did the right thing in changing out to a younger engine. Usually a spun bearing is bad for a lasting economy fix. The previous owner said everything was fine until an oil change at a fast change shop, then ticking.
My take on this is that maybe the oil ran low so they quick got an oil change with wishfl thinking that things will get all better. It is a shame because the engine is clean inside. A real waste for all the good machining of a proper operating engine. You never know what you will find in a used car. In my case bad rod bearings that sounded just like a tappet tick. Even shorting out cylinders did not reveal anything definate.
That is the the rest of the story. Thanks for the comments along the way.
Rick.