2012 XL Denali, 130K miles.
Some history, long-winded but bear with me.
Oil pressure sensor and screen was replaced last year due to cluster gauge going wacky.
I bought this with about 82K miles, maintenance history was good, dealer oil changes every 5-7K.
I changed the oil when I bought it and ran Mobil 1 5W-30 and changed every 5K. At about the 118K-ish mile mark, I would hear a very light, occasional tick when pulling through a drive-thru, and would go away if I raised the RPM slightly.
I figured since this was near the end of the oil change interval, perhaps the oil was thinning, oil pressure on the gauge was just above the 20 PSI mark, idling, hot engine.
So I wanted to try some Redline 5W-30/NAPA Gold filter and that solved the hot, ticking issue, again, this was a random tick and nothing continuous.
Near the end of that oil change interval, which went a little long to about 6K miles, it started ticking again but this time it would be a random tick, like....tick,tick..........tick..........tick, tick, tick.....................tick,....etc. It sounded like the lifter was starting to varnish up and barely hanging up.
I changed that oil with another dose of Redline but had a M1 filter and this time the tick didn't go away at first, took about 500 miles. Then at the end of a 1000 mile road trip, and 2500 miles on this oil, the tick started again but was more consistent, and would go away if I raised the RPM to about 900-1000 RPM.
For the sake of science, I drained that oil and did a 5 quart Valvoline 5W/30 and 1qt MMO treatment, PF-63, then the next day I added 1 can of Liqui-Moly Hydraulic lifter additive.
The oil I drained with 2500 miles, had no metal, no flakes, but a small layer of a velvety-dusty goop and maybe what the last few oil changes was breaking up. Not alot, but maybe a couple finger tip amounts.
I currently have about 100 miles on the cleaning concoction of oil, MMO, Liqui-Moly.
The symptoms seem to be improving slightly. The tick usually doesn't happen until about 20 sec after I start the engine when hot, but sometimes it will happen right away.
If I raise the idle, it tends to stop.
If I shut the engine off and restart, it sometimes takes about 10-15 sec to start up.
I drove home from work, about 30 miles today and it was quiet. I let the engine idle for 20 min and it was quiet. I ran an errand today after it cooled and it came back at idle.
Sometimes it will tick at half cam speed, and stay very consistent.
This is hit or miss, but I have some questions...
Could this possibly be the O-Ring restricting some volume and not pressure? Or does a bad O-ring only drop pressure?
My hot oil pressure reading on the sensor displayed in Torque is 21-23 PSI at a hot idle, oil temps at 200-210 deg,.this is also with a slightly thin oil/MMO mix.
It sounds like it's either cyl 4,6,or 8, hard to tell, but on the pass side.
Engine runs fine, smooth idle and smooth power.
Not an exhaust leak or loosen spark plug wire, it almost sounds like a spark but definitely a lifter....again, high-pitched, light tick.
I'll get some videos posted shortly.
Some history, long-winded but bear with me.
Oil pressure sensor and screen was replaced last year due to cluster gauge going wacky.
I bought this with about 82K miles, maintenance history was good, dealer oil changes every 5-7K.
I changed the oil when I bought it and ran Mobil 1 5W-30 and changed every 5K. At about the 118K-ish mile mark, I would hear a very light, occasional tick when pulling through a drive-thru, and would go away if I raised the RPM slightly.
I figured since this was near the end of the oil change interval, perhaps the oil was thinning, oil pressure on the gauge was just above the 20 PSI mark, idling, hot engine.
So I wanted to try some Redline 5W-30/NAPA Gold filter and that solved the hot, ticking issue, again, this was a random tick and nothing continuous.
Near the end of that oil change interval, which went a little long to about 6K miles, it started ticking again but this time it would be a random tick, like....tick,tick..........tick..........tick, tick, tick.....................tick,....etc. It sounded like the lifter was starting to varnish up and barely hanging up.
I changed that oil with another dose of Redline but had a M1 filter and this time the tick didn't go away at first, took about 500 miles. Then at the end of a 1000 mile road trip, and 2500 miles on this oil, the tick started again but was more consistent, and would go away if I raised the RPM to about 900-1000 RPM.
For the sake of science, I drained that oil and did a 5 quart Valvoline 5W/30 and 1qt MMO treatment, PF-63, then the next day I added 1 can of Liqui-Moly Hydraulic lifter additive.
The oil I drained with 2500 miles, had no metal, no flakes, but a small layer of a velvety-dusty goop and maybe what the last few oil changes was breaking up. Not alot, but maybe a couple finger tip amounts.
I currently have about 100 miles on the cleaning concoction of oil, MMO, Liqui-Moly.
The symptoms seem to be improving slightly. The tick usually doesn't happen until about 20 sec after I start the engine when hot, but sometimes it will happen right away.
If I raise the idle, it tends to stop.
If I shut the engine off and restart, it sometimes takes about 10-15 sec to start up.
I drove home from work, about 30 miles today and it was quiet. I let the engine idle for 20 min and it was quiet. I ran an errand today after it cooled and it came back at idle.
Sometimes it will tick at half cam speed, and stay very consistent.
This is hit or miss, but I have some questions...
Could this possibly be the O-Ring restricting some volume and not pressure? Or does a bad O-ring only drop pressure?
My hot oil pressure reading on the sensor displayed in Torque is 21-23 PSI at a hot idle, oil temps at 200-210 deg,.this is also with a slightly thin oil/MMO mix.
It sounds like it's either cyl 4,6,or 8, hard to tell, but on the pass side.
Engine runs fine, smooth idle and smooth power.
Not an exhaust leak or loosen spark plug wire, it almost sounds like a spark but definitely a lifter....again, high-pitched, light tick.
I'll get some videos posted shortly.
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