Mixing Synthetic and non-Synthetic oil together

[smd]

Hi, I was curious as to the % of synthetic oil in the Castrol synthetic blend oils. Castrol told me it was between 10 and 30%. In the past I have mixed their full synthetic with their GTX to make my own 50% blend. I was told that this was a bad idea and it shouldn't be done. It said on the bottles that the synthetic and non-synthetic oils are fully compatible, so I am a little confused. A long time ago the guys at Redline recommended that I make a similar 50% mix. Does anyone know if there is a problem making my own blend?
Thanks.

 

[ARB1977]

I dont see as to why you cant mix...you should see some of the home brews people create.

 

[peking]

It's not a problem. I've done it many times before.

 

[Bill in Utah]

Look at the UOA forum for my 50/50 mix of;

Castrol GTX / Syntec
Castrol Syntec blend / Syntec.

The Castrol GTX ALONE had a better UOA BTW.

Personally not worth the effort IMO.

All in the same engine.

Take care, bill

 

[pbm]

I've done this for years with no problem at all. I usually stay within the same brand but I have mixed brands too. I read years ago that adding a percentage of full synthetic to dino could only make the dino better but since finding BITOG I'm not so sure. I think the problem is that you are 'diluting' both (additive packages and base oils) which were carefully engineered. I don't think you will have any problem as long as you run a reasonable OCI.

 

[[RT] ProjUltraZ]

i just did a super blend, i had a quart of Redline 10W-30, Mobil 1 supersyn 10W-30, and Castrol GTX 10W-30 dino

went out and bought two quarts Valvoline Max Life syn-blend 5W-30. + 2oz Auto-RX

and K&N filter, replaced 5W-30 PP and sending sample to Blackstone

 

[Bulli]

i blended 7 oils, 3 of them synthetics

 

[CharBaby]

I do it all the time. I buy so much oil on sale with rebates or closeouts. Some are fully synthetic and others are conventional. I usually use 3qts syn & 2 qts conv.

 

[PT1]

I have done it for many years in all types of vehicles. Never an issue. One rule of mine is if I have a real Frankenstein blend of all the used 1/2 quarts of stuff laying around then I go with a 3000 OCI.

 

[chet2]

some people say the additives arent compatible...i try to stay with same oil in car...or at least same visc

 

[phaphaphooey]

You guys are nuts. Reminds me of a witch making a brew in her caldron or something like that. 1 eye of newt, 1 liver of frog...

 

[thunderchild]

That is what I am using right now. I was in Wally World a few months ago and they had that BIG SALE on GTX. I usually use only Synth but at $9.99 a jug, I bought 10 jugs. Now I have all this GTX I have to use. I bought a couple of cases of SYNTEC and I now mix a 5 qt. jug of GTX plus 2 qts. of SYNTEC. All 5w-30 of course. An oversized Amsoil SDF-15 filter tops it all off. Yes I have a large stash of those also.

 

[02zx9r]

have always been under the belief that same brands oils are ok but not different brands, although people do it all the time and the motor still runs

 

[Benzadmiral]

Originally Posted By: phaphaphooey
You guys are nuts. Reminds me of a witch making a brew in her caldron or something like that. 1 eye of newt, 1 liver of frog...

"Round about the caldron go,
"In the poison'd entrails throw . . ."
[insert mad cackling here]

 

[Steve S]

Originally Posted By: chet2
some people say the additives arent compatible...i try to stay with same oil in car...or at least same visc
The additives are all the same and the oil can be mixed .

 

[glenncof]

I prefer not to mix, but I do.

I would not do a super long OCI (like 10K miles) with a blend without knowing what I was doing with testing or experimentation.

1st preference is same brand.

2nd preference is same manufacture. (like SOPUS's PP+QS)

There is some unknown risk but probably small so make a judgment.

 

[Mr Nice]

If you find super cheap oil, mix away. It won't hurt any.

Different brands, weights, ratings (SL & SM)....etc, its all good.

 

[speedyswede]

No problems here...My current syn/dino mix:

-2qts Valvoline Synpower 5w30
-2qts Mobil Clean 5000 5w30
-12oz Lubegard Bio/Tech

 

[GMFan]

No problems with my oil fill in my signature. Probably have a quart of Pennzoil in there that I topped off with.

 

[electrolover]

i think pyb will mix with anything