Where's the lead and moly coming from?

[Hawkfanatic]

I bought a 91 Pontiac Firebird Formula in August '12. It had sat previously for about 5 years, so I had to replace alot of the fuel system to get it running. Since then, I have put about 10k miles on the car and every UOA shows high lead content. The car runs great and has no leaks. At the last oil change, I happened to check the oil before I drove it to get it warmed up, and it was about 1.5qts down, which I noted on the form. I think it was like that since the last OCI, as I have not lost any oil in the last 1k miles.

Oil has always been Mobil 1 0w30 and a Purolator filter.

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[walk23]

Lead is an indicater of wear. Moly is an additive in the oil to reduce wear.

 

[440Magnum]

If a previous owner ever decided to run a lead additive or leaded racing fuel in the car, say for track days or something, then that could explain it- it takes a long time to wash out of the nooks and crannies when its been used as a fuel additive.

However, you're not exactly showing a steady downward trend, so there might be an issue with bearing wear going on. Hard to say- those numbers aren't stupid-high, but they're a lot higher than I'd like to see on that type of engine.

 

[bullwinkle]

Just curious-is it the 0W30 AFE M1 or the regular? I didn't have the greatest luck with the AFE myself, maybe the M1 HM in 5W30 or even 10W30 might be better, especially using 1.5 quarts in only 4K-maybe the HM would slow that down a bit.

 

[Hawkfanatic]

Thanks for the replies.

440- The car is pretty stock, so I dont see any reason anyone would put lead additives or race gas, but its a possibility.

Bull- It is the AFE. I like the 0w30 because of the article on the home page that says the oil can never be too thin at startup.

 

[fdcg27]

Some of these GM engines just seem to shed a lot of metal.
Iron does look high, but that isn't all that unusual in an old-school GM V-8.
Lead?
I'd bet that some previous owner thought that this beast, which would have a hard time hitting the top speed of a four cylinder Accord, needed either a TEL fuel add or leaded fuel.
I'm sure that you're well aware of owners ascribing performance to their cars that they can't approach.

 

[Merkava_4]

That oil is not working for that Pontiac - at all. My gut feeling tells me the oil is too thin.

Try a 10W-40 High Mileage oil like MaxLife or PZ bronze bottle and report back.

 

[PhilsZ]

Lead, bearing wear. Maybe some corrosion on bearing journals from sitting so long (acids n such).

 

[dave1251]

Switch to a conventional 5W30 that is on sale run for two 5K OCI's then do a UOA. M-1 AFE is a fine PCMO but if you are not going to do due extended drains you are throwing away $$$.

 

[Hawkfanatic]

Ok, so its been a few OCI since, and lead is still higher than average. This last run was with 5w-30 Castrol Syntec to try and isolate if oil brand makes a difference.

Lead/mile is trending downward, so thats good, but still concerning.

 

[CT8]

Originally Posted By: Hawkfanatic
Thanks for the replies.

440- The car is pretty stock, so I dont see any reason anyone would put lead additives or race gas, but its a possibility.

Bull- It is the AFE. I like the 0w30 because of the article on the home page that says the oil can never be too thin at startup.
How do you know the article is not filled with half truths, opinions and outright lies?

 

[Greasymechtech]

Oil too thin or normal GM self clearancing bearings

Try the Castrol 0w30. Another is Mobil's ESP 0w30.

http://www.mobil.com/USA-English/Lubes/PDS/NAXXENPVLMOMobil_1_ESP_X1_0W-30.aspx