Synthetic Oil?

[f5fstop]

GM's testing on this engine does not require the use of synthetic oil. It won't hurt, but not necessary. As far as temp decreases, it is minimal, and remember, for efficiency, the engine must be running at a certain temp. The true advantage of syn oil is in extreme hot conditions (resistance to breakdown) and extreme cold conditions (flows at extreme cold temps).
If you want to find out how well non-syn oil is doing, send a sample for an oil analysis and see how the TBN is, to check the true oil life remaining.
For some people, using syn oil is similar to burning premium fuel.

[usetosellhummer]

Plain and simple, it won't hurt but you are the only one who can justify the cost. It is not a need.

[f5fstop]

Originally Posted by usetosellhummer

Plain and simple, it won't hurt but you are the only one who can justify the cost. It is not a need.

Exactly....

[BlueHUMMERH2]

I just put syn in my H2 at about 60K, and I think the engine runs much more smoothly. Just my opinion however.

[H3PAC]

Thanks guys...exactly what I was looking for.

[deserth3]

I switched to Mobil 1 EP at 3000. Haven't noticed any change in the engine or milage. But I do run offroad in 100+ deg temp in Utah.
I like the idea of not having to change the oil every other month.
Mobil 1 EP advertises it's good for 15000 miles or one year. I'll change it at 10k because of offoading. Maybe less depending on what the oil looks like.
You can probubly put it in and follow the computers recomended change without any problems. As one mechanic told me. The computers set to calculate for a moderate climate, no off road use, and normal driving.

[f5fstop]

Mechanic is incorrect.....Computer is not set to a moderate climate and is not set to any type of specific conditions.

The algorithms used by each PCM is different for each engine and vehicle application, since engines are different and even the same engine in a different vehicle will have different demands. Primarily, the computer looks at the engine oil temp upon startup, compares this to the air temp sensor for ambient temp, then looks at how long the engine stays at a specific temp while operating. It also monitors engine RPM and a few other inputs, then constantly compares this information to the internal algorithms for the oil life monitoring system.
Running cross country non-stop on a nice summer day will allow for long change intervals; short trips in the middle of the winter will cause short change intervals, since cold temps and engines that do not get to operate for a period of time hot, will damage oil. Extreme hot condition such as engine overheating will also cause a shorter engine oil change interval. In addition, the running time of an engine at a normal operating condition over a period of time burns off any moisture inside the engine.

The oil life monitoring system cannot determine the type of oil you are using; however, the algorithms are set for a specific type of oil, in the case of the H3, it is set for oil that meets GM spec GM6094M. Using an oil of a lesser spec will not give accurate results, thus you could damage the engine. Using a more stringent oil life spec such as that for synthetic oil GM4718M, will also cause the oil life indicator to be inaccurate; however, since this type of oil is better, will last longer, and is not as affected by heat/cold, no engine damage will result. (The spec of the oil allows the programmers to know the oil life under all types of operating conditions; thus, the engine oil life monitoring system can accurately determine when this oil will fail inside your engine, based on your engine's driving conditions.)

In addition, the oil life system cannot determine dirt in the engine. The algorithms are made up for a closed intake system, with a factory spec paper air filter. If you are using a type of oiled foam air filter, or have a leak in the intake system that could draw in more dirt, the oil life system will not be accurate. Oiled foam filters are noted to not filter the dirt as well as a standard reliable paper filter.

Also, the oil life monitoring system does not care if you are off-roading or on a hwy, it calculates the same way.

(Should I also note that Mobil EP does not carry a spec for either of the above approved GM Specs?)

[Wisha Haddan H3]

afaik, only Mobil 1, Chevron Supreme Synthetic and Texaco Havoline Synthetic meet the GM4718M spec for synthetic oil. Not that every other synthetic is worthless ... they just may not be certified yet.

I'm a big fan of Mobil1 and have used it in all my vehicles. Makes cold startups a LOT easier.

[f5fstop]

Not really, Valvoline, Pennzoil, Amsoil ASL (Amsoil XLF full syn, Group III, does not, but it meets the 6094 spec...go figure that one, since both are labeled full synthetic), and Castrol also meet the GM synthetic oil spec, in their respective FULL synthetic oils. There may be others too, but these I know for sure do meet the spec (4718).
In addition, Mobil 1 and Amsoil's ASL are the only two PAO/Group IV synthetic motor oils on the market. The remainder, including Amsoil's XLF are Group III hydro-cracked synthetic oils. This last bit of info basically means nothing since the important thing is the oil meets or exceeds the GM required spec.