1999 Pontiac Firebird- 3k mi - Mobil 1 10W-30 HM

[ThirdeYe]

I had this oil changed early since it was in service for so long, while sitting for months during the winter. I also drive this car hard from time to time, and fully expected to see higher than average wear metals. Lastly, I wanted to see if I had the dreaded GM intake manifold gasket leak. The oil used was Mobil 1 High Mileage 10W-30, in service for around 7 months, including some below freezing temperatures. My thoughts are that the potassium and sodium seem higher than I would like. The last 3 oil changes have been with oils that should not contain sodium or potassium. The OLM said that I could have gone twice as long (approx 6k miles), so I may end up running at least 5k next time. I was quite impressed with the wear numbers. Any thoughts?

 

[Pontual]

Good! Looks like 6k is pretty doable on those conditions.

 

[Merkava_4]

Thanks for the test. I will now cross M1 HM 10W-30 off my list of possible purchases.

 

[aquariuscsm]

Hey Derek I can't remember,is this the first UOA you've done on this car?

 

[aquariuscsm]

Here's my UOA of M1 10W40 HM. Wanted to post it here alongside of yours to compare the add packs of the 10W30 vs the 10W40. The Mobil 1 is the 3000 mile run and the 3200 mile run is RP 20W50 (Synerlec formula) The add pack in yours Derek looks stronger than mine:

 

[CarbonSteel]

Originally Posted By: Merkava_4
Thanks for the test. I will now cross M1 HM 10W-30 off my list of possible purchases.
Do tell why? I am sure the answer will be ever so revealing...

 

[ThirdeYe]

Originally Posted By: aquariuscsm
Here's my UOA of M1 10W40 HM. Wanted to post it here alongside of yours to compare the add packs of the 10W30 vs the 10W40. The Mobil 1 is the 3000 mile run and the 3200 mile run is RP 20W50 (Synerlec formula) The add pack in yours Derek looks stronger than mine:

Yep, this is my first UOA with this car and my 3rd oil change since buying the car last year. 2 runs have been with M1 10W-30 HM and 1 was with Pennzoil HM. Now using QSHP, all in 10W-30. Your UOA looked amazing compared to mine! Though I'm sure the 'Bird will soldier on for as long as the intake manifold gasket hangs on.

 

[aquariuscsm]

What does calcium do in an oil? I just noticed the calcium in my M1 10W40 is 3160. Your 10W30 has higher moly and zinc.

 

[ThirdeYe]

I forgot to mention in the original post that during this OCI I ran a tank that had Stabil in it along with a tank that had Royal Purple Max Clean in it. Not sure if any of those contained any potassium or sodium that would've leeched into the oil through combustion, but I thought I'd mention it.

 

[ThirdeYe]

Originally Posted By: aquariuscsm
What does calcium do in an oil? I just noticed the calcium in my M1 10W40 is 3160. Your 10W30 has higher moly and zinc.


Calcium acts as a detergent, much like sodium does in some oils. Here's a brief article about it: http://www.pqiamerica.com/calcium.htm

 

[bbhero]

Does look really good

I hope that Bird flies for a long time.
Always have liked those cars since I was a little kid in the early 80s.

 

[Merkava_4]

Originally Posted By: 2010_FX4
Do tell why? I am sure the answer will be ever so revealing...


11/11/2 for only 3000 miles is ridiculous as heck.

Glad somebody else with a 3800 ran that test and saved me from all the wear.

 

[CarbonSteel]

Originally Posted By: Merkava_4
Originally Posted By: 2010_FX4
Do tell why? I am sure the answer will be ever so revealing...
11/11/2 for only 3000 miles is ridiculous as heck. Glad somebody else with a 3800 ran that test and saved me from all the wear.
One UOA does not a trend make...

 

[ThirdeYe]

Originally Posted By: Merkava_4
Originally Posted By: 2010_FX4
Do tell why? I am sure the answer will be ever so revealing...


11/11/2 for only 3000 miles is ridiculous as heck.

Glad somebody else with a 3800 ran that test and saved me from all the wear.


I don't think it's too bad considering how much fun I have with the car and how long it was in service. The wear numbers I am happy with, just unsure about a potential coolant leak.

 

[53' Stude]

Nice UOA and disregard Merk's comments.

 

[buster]

Originally Posted By: car51
Nice UOA and disregard Merk's comments.


+1

This is the older HM formulation.

 

[burchster13]

If your worried about the coolant leak and can afford it just have the gaskets changed. I did that with my Lesabre 3.8 and the mechanic said it was a good idea even though it wasn't leaking.

 

[KCJeep]

Bar's Leak intake manifold gasket stop leak worked for me on a couple of those GM engines.

 

[Garak]

Yes, those "wear" numbers are inconsequential, particularly in this engine family.

 

[ThirdeYe]

I'll test my next run of QSHP while keeping an eye on the coolant level and the look of the oil and see if those numbers go down. I still kinda wonder if it had anything to do with the Stabil and/or Royal Purple Max Clean fuel additives I've used.