Mixing oil?

[johnsmellsalot]

Is it ok to mix 2 different types of oil if they are the same viscostity? The reason I'm wondering is because my car takes 4.5 quarts to do an oil change. That leaves me with 1/2 quart.

I guess I could start buying 9 quarts at a time instead of 5 and use the same brand of oil twice. 9/2=4.5

But lets say I have Castrol GTX 5W-30 Conventional and Pennzoil 5W-30 Conventional. Is it ok to mix the 2?

 

[addyguy]

You can mix any modern oil with another oil. It doesn't matter.

 

[walk23]

No problem. I have mixed especially when doing a cleanup on a short run cycle.

 

[SLCraig]

I do this all the time to get rid of old single quarts laying around.
I've even done oil changes with 4qts where every quart is different. Sometimes even different viscosities. My old Saturns did not care what they got

 

[dparm]

It's not optimal, but it will work.

 

[ARCOgraphite]

If absolutely required, I would try to mix two that use the same add pack, if possible. Oil Co's will tell you that it is not a good idea to mix low/mid saps products, and I would definitely not do it in a race application unles the mixture was proven. True, the Oils will not gell or explode, but you might worsen (or improve?) the EP and cold AW properties.

 

[chubbs1]

Don't worry about mixing for general driving in PCM's. Even guys who race mix oils with good results. Sleep well.

 

[someguy]

Some mixing happens whenever you change brands since you never really drain out all of the old oil.

 

[CaspianM]

It is ok to mix but best not to do it on regular basis.
I usually avoid mixing brands or different class of motor oil.
Stick to one single routine for consistency.

 

[shrooms]

People have been mixing for years and the junk yards are not full of cars as a result.

 

[mongo161]

I do it all the time with good results. I try to keep the oils in the same family, SOPUS, Kendall, Valvoline, Mobil, Castrol and use different weights.

I'm currently running Shell Rotella, Triple Protection, Dino in 10W-30 HD oil with Formula Shell, Dino, 5W-30 in SM, with fine results so far with over 5K on the blended mix. The oil is still Golden Orange and the only dirt I see is some minute specks....only when I wipe off the dip stick.

I wanted to use a HD Dino oil and mixed it with a Dino conventional in the same Family....Shell, SOPUS.

My T4R has run very smooth with this blend and I hope to use it again next summer for the heat and high speed highway driving.

I've also mixed some blends for Family, Friends and Neighbors using these Diesel oils....Castrol Tection, Valvoline Premium Blue, Kendall with Titanium, Chevron Delo, Shell Rotella. All of these Diesel Dino Oils were in the 15W-40 weight and I mixed them with lighter Dino/Synthetic oils in the same family.

All of these Diesel Dino oils in the 10W-30 and 15W--40 are API-SM and CJ-4 for "Mixed Fleet" use.

NYC is severe driving with lots of short trips, hot temps, long idling in traffic jams and if these oils are used in fleet vehicles like Taxi Cabs, Limos and Delivery Vans they should perform just as well in PCM. I've had nothing but positive feedback from these folks on the OC mixed blends. All of these vehicles were older...most older than 7 years. I would not suggest anyone to use Diesel Dino in a mixed blend for a new vehicle under warranty.

Just my humble opinions.......

 

[84zmyfavorite]

Today, I mixed 3 quarts Kendall 5w-30, 1 quart Pennzoil Yellow 10w-30, 1 quart Havoline 30HD and 1 quart SuperTech 10w-30 for a High performance oil change in a 2001 Jeep Cherokee. I think the Jeeps in Love.

 

[Triple_Se7en]

Originally Posted By: CaspianM
It is ok to mix but best not to do it on regular basis.


Not true! I've been mixing for 300K / 16 years and engine runs great / quiet.

 

[ARCOgraphite]

Originally Posted By: mongo161
...
I'm currently running Shell Rotella, Triple Protection, Dino in 10W-30 HD oil with Formula Shell, Dino, 5W-30 in SM, with fine results so far with over 5K on the blended mix. The oil is still Golden Orange and the only dirt I see is some minute specks....only when I wipe off the dip stick.

.....
That is one of the lucky mixtures that "seems" to work well - I did that on my older forester to quell engine noise.
- Engine teardowns done when developing oil formulations for low saps products show that subtle misbalancing of EP and AW agents showed moderate to severe wear increases in API sequence testing. There is NO arguing with this hard data! All you guys have here is unsubstantiated opinion. Read some Patent applications available on the web and educate yourselves. The oft repeated "I've been doing this mixing for 20 years ..." doesn't apply to current formulations.

 

[TFB1]

Originally Posted By: mongo161

I'm currently running Shell Rotella, Triple Protection, Dino in 10W-30 HD oil with Formula Shell, Dino, 5W-30 in SM, with fine results so far with over 5K on the blended mix. The oil is still Golden Orange and the only dirt I see is some minute specks....only when I wipe off the dip stick.

So where are the deposits that normally darken the oil with usage??? Are you saying this concoction stops this process???

Frankly if I'd run oil 5K mi and it was still clean, I'd be concerned the oil wasn't holding the contaminants in suspension...

 

[ahoier]

It's strange, my last 3k OCI, I was using "Mopar Motor Oil" from the Dodge Dealer, about 2.5k into the OCI, I had to top off.....reached for the first bottle I found, happened to be Mobil 1 5W20....note: car specs SJ 5W-30 "Energy Conserving Oil" - well, after I added the Mobil 1, I noticed the dip stick oil color was actually darker then the PYB

But yea, that would be real strange to have a 5k OCI, and still have clear/tan motor oil.....I'd be concerned....

 

[mongo161]

This nice Golden Orange color of the Dino oil tells me that my engine is clean. The last run of oil was PYB 5W-30 that was relatively clean after a 6K run of mixed driving.

I'm not at all concerned about the color of my oil...its the performance of my engine..... since the blended mix contains Shell Rotella which has very good detergents and cleaning agents. These Rotella Diesel oils are formulated to hold any dirt, if any, in suspension while the oil continues to protect your engine. Formula Shell is also a very good oil with lots of Moly.

I'm extremely pleased with this mix for the heat of summer, especially on some long distance, sustained high speed driving in high ambient temps. This mix of quality Shell oils in Rotella and Formula Shell will hopefully be my summer mix for severe driving.

 

[johnsmellsalot]

On my mom's Civic, I change the oil according to the oil life moniter. It's probably been at least 5,000 miles since the last oil change and the oil is still clean. There is 15% left on the oil so the car is soon due for a change.
Originally Posted By: ahoier
It's strange, my last 3k OCI, I was using "Mopar Motor Oil" from the Dodge Dealer, about 2.5k into the OCI, I had to top off.....reached for the first bottle I found, happened to be Mobil 1 5W20....note: car specs SJ 5W-30 "Energy Conserving Oil" - well, after I added the Mobil 1, I noticed the dip stick oil color was actually darker then the PYB

But yea, that would be real strange to have a 5k OCI, and still have clear/tan motor oil.....I'd be concerned....

 

[mongo161]

Yes Arco.....these mixes work really well in the heat of summer for long distance sustained driving in high ambient temps and a lot of traffic jams and stop and go traffic! NYC taxi cabs, limos and delivery cars and vans swear by HDEO for severe driving conditions. I just like to thin it out a bit with conventional Dino, or add some synthetic or synthetic blend to the mix.

The durability and cleaning agents in Shell Rotella Triple Protection Dino and the powerful add pack in Formula Shell with all of the Moly seems to be the key. IMO....they might use very similar base oils in both products.

Before I even contemplate mixing any oils, in the same family, I call the Oil Company....Shell, Castrol, Valvoline, Kendall, Mobil and ask if there is any issue with my proposed mix. Their response to my suggestion of 15W-40 oils are usually.....that is heavier than you need for your application. Then I explain that I want some of the properties of the Diesel mixed with PCMO to thin out the mix....and I offer my proposed mix. I have never been warned that I would damage my, or others vehicle, and have had great results on cleaning and durability. So there you have it....Thanks.



Originally Posted By: ARCOgraphite
Originally Posted By: mongo161
...
I'm currently running Shell Rotella, Triple Protection, Dino in 10W-30 HD oil with Formula Shell, Dino, 5W-30 in SM, with fine results so far with over 5K on the blended mix. The oil is still Golden Orange and the only dirt I see is some minute specks....only when I wipe off the dip stick.

.....
That is one of the lucky mixtures that "seems" to work well - I did that on my older forester to quell engine noise.
- Engine teardowns done when developing oil formulations for low saps products show that subtle misbalancing of EP and AW agents showed moderate to severe wear increases in API sequence testing. There is NO arguing with this hard data! All you guys have here is unsubstantiated opinion. Read some Patent applications available on the web and educate yourselves. The oft repeated "I've been doing this mixing for 20 years ..." doesn't apply to current formulations.