2004 Chevy Impala 3.4 Mobil 1 5W30 5.5K OCI. High lead?

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Aug 2, 2022
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Location
Arkansas
Alright guys. Here we are. This car I bought with 48K miles on it several months ago. Being that gas was so expensive I bought it, not to mention I've been around GM my whole life. I know these engines are known for intake and head gasket failure. Me being proactive replaced both before putting it on the road. However this is the first oil sample since replacing all of that. The car looking at the gasket had a leak in ONE of the heads. This report kinda worries me. I get why silicon is high and such but the rest like lead bothers me. Opinions? @OVERKILL @kschachn I always value your opinions?

Car sounds and drives GREAT! This report kinda worries me lol.
 

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Some high wear metals there!
Yes it is. I'm thinking they will clear up with the oil change I have now. Much of this in my view is from the residual leaky gasket before I got to it. Car only has 55k miles on it and runs like a dream. All while getting 34mpg in interstate lol. Around 28 on average. Love this grandma car 😂


I seen many of these 3.4s with over 300K miles. Hoping I make it there.
 
The potassium is definitely an indicator coolant has been in the crankcase. It may take a few OCIs to flush out contaminants. If it were mine I would drive it as normal while keeping and eye on coolant levels and do another UOA 1 or 2 OCIs from now

Edited to add:
I had same engine in a 2003 Monte Carlo. IM gasket had been failing for a long time before realizing it. Had major sludge in oil filter and sludge visible through oil fill hole. Took at least 2 oil changes to clear it up. I’m sure there would have been high wear metals had I done a UOA. Drove that car many more miles after repair.
 
Yes it is. I'm thinking they will clear up with the oil change I have now. Much of this in my view is from the residual leaky gasket before I got to it. Car only has 55k miles on it and runs like a dream. All while getting 34mpg in interstate lol. Around 28 on average. Love this grandma car 😂


I seen many of these 3.4s with over 300K miles. Hoping I make it there.
Only 55K, man that's practically a brand new car, right on! Those are really nice cars(y)

I agree about the oil analysis, I bet the next one will look much better.
 
Drive it for maybe 3,000 miles, then change it and sample again. If things are OK, you should witness these elevated items trend down. If they don't, you have a problem. You could also do it shorter if you feel so inclined, depends on how much you drive.
 
The potassium is definitely an indicator coolant has been in the crankcase. It may take a few OCIs to flush out contaminants. If it were mine I would drive it as normal while keeping and eye on coolant levels and do another UOA 1 or 2 OCIs from now

Edited to add:
I had same engine in a 2003 Monte Carlo. IM gasket had been failing for a long time before realizing it. Had major sludge in oil filter and sludge visible through oil fill hole. Took at least 2 oil changes to clear it up. I’m sure there would have been high wear metals had I done a UOA. Drove that car many more miles after repair.
What gets me is the oil that was in it indicated zero coolant/water. I did notice the overflow would bubble when car was idling. One of the main reasons I tore it down and replaced H/IM gaskets. And when I looked at the gasket itself it looked like a slight crack in the cooling passage but then again it didnt. It had a ever so slightly leak I'm assuming by the evidence, it never even overheated.
 
Drive it for maybe 3,000 miles, then change it and sample again. If things are OK, you should witness these elevated items trend down. If they don't, you have a problem. You could also do it shorter if you feel so inclined, depends on how much you drive.
I thought 4k but maybe I'll change at 3k and send in another sample.

My understanding is a coolant leak also drives up moly, hince the increase on the report. It seems a bit high compared to most mobil UOAs. Though it may have been the triple action...I dont remember the bottle saying it when I changed it though. 🤔
 
Do several short OCI’s with inexpensive 5W-30 to flush out contaminants, it will take a while. Engine has most likely been leaking a bit for a while, and there will be small amount of oil/coolant ‘muck’ all over the engine.
 
I have 98 lesabre.attempted intake manifold gadkets, couldn't get the intake too seal,and with a digital torque adapter you put on ratchet..AC Delco made.5 times on,off,onoff,. That bars leak Intake and manifold sealant in bottle..sealed everything up. Buick still running today,no coolant leaking.
 
UPDATE: I dont like this lol. However this I poured from the oil filter this morning, so I expect it to be not the cleanest. Still makes me un easy for sure. Oil has about 2k miles on it since old oil was drained and the bad uoa report. Guess it's time to change it again. I did however put a fram Ultra synthetic oil filter which supposedly filters down to 20 microns today (I had used the regular Ac delco OEM until today). Thinking I will run this oil another week then change and new filter. I want this crap out of my engine.

I'm seeing small metallic. The round circles you see is air bubbles lol. It's just super fine metallic crap. Well bearing material lol.

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