Going to a Cheaper Oil

[PeterVX2]

I have a 2002 VX II Commodore Equipe that I use as a second car, local trips, risky trips to the supermarket etc. It has just passed 230,000 KLM.

I have been changing the oil every 5,000 KLM because letting it go to the 10,000 KLM, the oil ended up very dark ( probably due to piston ring blow by or sloppy valve guides )

All this time I have been using the Castrol Magnatec 10 W 40.

I have been really happy with this in the earlier life of the car but I notice it has changed its formula over the years.

I just recently decided to use a cheaper mineral oil because I change it every 5,000 KLM.

I use a Valvoline 15 W 40, it was half the price of the Magnatec.

To my surprise, the motor seemed quieter and smoother.

I did a fuel consumption check using a full tank and again to my surprise, I dropped from the usual 10.5 to a 9.2 Litres per 100 KLM. This was a mix of both local traffic and a bit of 100 klm open road driving.

This is a big difference.

On paper a 14W40 is really no different to a 10W40.

At operating temperature, both have a 40 rating.

Could it be that the Magnatec is a semi synthetic ?

Are older worn motors better of with a thicker mineral oil ?

Does the slightly thicker oil seal rings and valve guides a little better ?

Would appreciate any informed comment on this.


Cheers All

 

[jeepyrocks]

Strange but not unheard of. Does it use any oil between changes? Ecotecs will generally accept any oil, but you are right about the difference in sound/smoothness; My other half has a VY with 260k on it, and we usually run mobil 1, but recently castrol edge was on sale, so it got a dose of that (5w30) - well I'm bloody annoyed as it has a noticeable tappet clatter on cold start and just doesnt seem as smooth. This is a synthetic to synthetic change though. Fuel economy seems the same.
Slightly thicker only at cold wouldnt have too much difference perse', but there is masses of posts on the bob is the oilguy forum where people have had all kinds of experiences with different oils and grades. I'd say if the car is happy on it, not using any, and you continue the 5k change intervals, then stick to it.
You've made me think about throwing in some conventional dino oil and seeing how well we go!

 

[EYY]

Use the cheapest stuff you can find and change it often.

 

[lout]

ours have 290,000km and 320,000km
i used mobil1 5/30 up to 200,000km and then switched to mobil1 10/40 high mileage (ebay)
both run and sound like new use around 0.5 to 1.0 litre over 10,000km
i was using valvoline in my 78 pontiac but was never happy with it
pontiac has hydraulic lifter cam
now using mobil1 high mileage in them all

 

[VK SL 3800]

The viscosity in them is the same but the chemicals would differ, have a look on the bottle and find the API rating, The latest Synthetics are SN i think, some of the older stuff will be SG.

An Ecotec was released and probably optimised with an SH or SJ grade oil as that was the latest and greatest so that may be why it runs nicer on it.

 

[devilly]

i always have believed that it depends on the temperature, so in winter thinner oil and in summer thicker oil,but i have found with my car that over many oil changes it seems to like the 15w-40w in winter and summer and LOVES the ryco oil filter.i have been watching the pressure and researching it a bit via my oil gauge.

 

[Fulysic]

Sometimes cheaper oils are fine i like the higher end stuff, but friend of mine uses auto store brand stuff in his everyday VT with no issues i think he is approaching 300,000 just because its high k's does not really mean to much if its been looked after, you can get low k's and find motors worse if it's had rough life

So some of it comes down to cars history and driver

I used to use Magnatec in my partners car but as of recent i changed oil type as Magnatec didn't seem to be performing like it used to 6 moths ago

 

[PeterVX2]

Gentlemen,


Thank you all for your replies.

My oil usage between 5,000 KLM changes is 0.2 to 0.3 litres. Seems to use more on a highway trip. The oil usage is the same for the Magnatec 10W 40 and the mineral 15W 40 Valvoline oil.

I have now done a little over 4,000 on the cheaper mineral oil and the motor is still much quieter that using the Magnatec. Oil also looks a little cleaner than the Magnatec for this number of K's.

Will stick with the cheaper oil for now.


Cheers All

 

[Jxfwsf]

Seems like slightly thicker mineral oil is doing a better job sealing the rings and keeping all the crap from the combustion process on the correct side of the rings then if it's cleaner.

What discolors the oil is the detergents in it cleaning the crap out of the oil galleries/block/heads, but mainly the byproducts of the combustion process getting past the compression rings.
I wouldn't be scared to throw 20w50 in it next time and see if the 200-300mL consumption drops more on a 230,000Km donk.