'94 Pontiac Grand Am GC Green 7518 OCI 182791 car

[benjamming]

Code:


Oil used GC Green GC Green AMSOIL XL-7500 5W30 AMSOIL XL-7500 5W30 Chevron Supreme SL 5W30 Chevron Supreme SL 5W30

Sample Date Jan-27-2008 Mar-18-2007 Apr-8-2006 Oct-22-2005 May-7-2005 Mar-5-2005

Miles on oil 7,518 7,520 7,451 7,353 2,903 912

Miles on car 182,791 175,273 167,753 160,302 152,949 150,046

Time on oil 10 months 11 months 6 months 6 months 2 months

Make-up oil 0.0 qt 0.0 qt 0.0 qt 0.0 qt 0.0 qt 0.0 qt

Oil filter EaO K&N AMSOIL SDF ValuCraft Wix Micro-Gard

Air filter AMSOIL AMSOIL AMSOIL AMSOIL AMSOIL AMSOIL

Fuel adds AMSOIL PI NEO/None NEO None None None

MPG 26.2 24.2 25.4 26.8 25.3 24.0

Lab Dyson Blackstone Blackstone Blackstone Blackstone Blackstone

Notes Cleaned air filter Replaced coil Cleaned air filter ARX 2nd rinse ARX 2nd clean



Iron: 16 20 10 10 7 3

Copper: 13 7 7 7 2 1

Tin: 0 0 2 1 1 0

Lead: 32 20 25 18 3 0

Chromium: 1 0 0 1 1 1

Nickel: 1 0 0 0 0 0

Aluminum: 4 4 4 3 2 1

Titanium: 0 0 0 0 0 0

Silver: 0 0 0 0 0 0



Calcium: 2422 2973 2640 2604 1296 825

Magnesium: 193 144 27 32 17 2

Zinc: 1030 963 731 776 600 367

Phosphorus: 1035 762 632 649 487 358

Barium: 0 0 0 0 0 0

Molybdenum: 5 15 15 40 312 185

Antimony: 0 NT NT NT NT NT



Silicon: 31 22 16 19 15 3

Sodium: 44 36 24 28 16 8

Boron: 3 5 3 7 25 26

Potassium: 1 5 2 1 1 0

Vanadium: 0 NT NT NT NT NT

Manganese: NT 1 0 0 0 0



Viscosity 40C: 74.3 NT NT NT NT NT

Viscosity 100C: 12.1 65.0 54.8 57.9 58.2 58.6

TAN: 2.73 NA NA NA NA NA

Flashpoint: 340 405 380 390 390 380

Oxidation: 23 NT NT NT NT NT

Nitration: 14 NT NT NT NT NT

Water: 386 0.0 0.0 0.0 0.0 0.0

TBN: 4.0 3.1 2.8 3.1 2.7 4.3

Fuel: 1.12
Soot: 0 NT NT NT NT NT

Insolubles: NT 0.4 0.4 0.4 0.4 0.3

Glycol: 0 Trace ? 0.0 0.0 0.0

VI Index: 161 NT NT NT NT NT

Sulfate by-product: 29 NT NT NT NT NT


The air filter was cleaned at the beginning of the current interval.

Terry's lab uses KF for water reporting. Also, Terry's lab uses the closed cup method for flashpoint. B/S uses open cup.

Driving style changed dramatically over the course of this interval so don't read much into that #. It is steady now though with a 25 mile trip each way to work (~ 30 min).

Coolant level hasn't changed any noticeable amount. GM pellets are in the system with less than 10k miles on them. AMSOIL coolant is in use.

Spark plugs had 30k miles on them at 180k miles. They will be changed very soon. I believe this will help as one of the many flavors of Bosch is currently installed. NGK copper (V-plug?) has been purchased but may not be optimum - taking suggestions.

There appears to be a fair amount of wear going on. What say ye? GC is a good oil - look at that flashpoint with the fuel %.

Oil & filter were changed at sample. Oil - VP Racing RS530 5W30. Oil filter - AMSOIL EaO. Suggestions welcome for next recommended OCI.

 

[ATS-V]

Don't overlook PCV and O2 sensors.

 

[addyguy]

Overall, you car seemed to do best on the Amsoil. You came close with the GC, but still did better with the XL-7500. I'd go back to that. GC is a great oil, but it doesn't give the best results in all circumstances - and GM's iron V-6 and V-8 engines seem to be one of them - another member got much better results on a V-8 truck on PC dino than on GC....can dig up the link if you want....

 

[glennc]

Obviously the wear metals are up a good bit and, yes, it looks like the XL may have done a better job than the GC overall in protecting the engine. The Si and flashpoint/fuel numbers you've already alluded to, and those may have something to do with the increase, but with your mileage at a relative high it seems your driving must have been fairly easy on the car with not too many short trips or cold-driven miles, so the higher numbers are a little bit surprising.

If you're into experimentation but don't want to change to a conventional oil, have you thought about PP or Maxlife synthetic? I'd bet you'd see improved results with either one. Or if you like the offbeat oils, RP?

Overall it looks like a perfectly decent result that is not indicative of any actual problems. Out of curiosity, with the car approaching 200k miles, how much longer do you plan to keep it?

 

[glennc]

Where is the sodium coming from? Did the lab make a note of it? It does seem to be trending upwards more or less in conjunction with wear numbers....

 

[benjamming]

Lab did make note of the sodium.

I plan on keeping the car until tragedy strikes...

 

[glennc]

I guess that explains the wear trend. Why use expensive oil? Already have a stash? Why not use cheap good oil and change it more frequently?

 

[benjamming]

This isn't expensive oil. I bought a couple cases when AZ had oil sales. It was less than $4/qt for sure. I want an oil that will hold up to fuels & coolant better than others. PP is indeed a good oil. The other thing is that I have a stash of other oils. I also have a case of Redline 5W30 when AA was getting rid of their supply. The VP racing oil was when they were getting rid of that flavor as well.

 

[glennc]

Yes, $4 a quart isn't bad I suppose. I'd still run something half the price and shorter OCI and think it would do better. If you have coolant leeching into the oil somehow then it will have an exponential effect over the OCI span. Much more damage towards the end than at the beginning.