Would you mix brands of oil?

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Originally Posted By: UltrafanUK


When you mix oils it does not improve things and the final result will depend on how poor the quality of the worst sinner in the collection of cans was.


Any basis for that? Seems rather a blanket statement for what will be a rather complex phenomenon.

Its probably true for, say, base oil stability, but the effect of additives (which are probably a significant quality differentiator) seems likely to be...well...additive.
 
STP is now the house brand for Advance Auto. I would use it with no qualms at all.
I mix oils all the time, as do millions of others that add whatever oil to what is in their engine when low.

I have mixed 4 qts before and no issues.
 
When mixing brands I prefer to stay within ones that have similar add packs. The MaxLife is high sodium and doesn't fit with the other 3. The STP is high on Boron. At least the QSUD and Havoline are fairly similar. I prefer not to mix Valvoline/Napa oils with anything else. For a short OCI not much to worry about though.
 
I try not to mix brands unless I got a good excuse. You might not get the entire benefit of a brand's additives. One brand's additives might dilute the other brand's additives.
 
Originally Posted By: Ducked
Originally Posted By: UltrafanUK


When you mix oils it does not improve things and the final result will depend on how poor the quality of the worst sinner in the collection of cans was.


Any basis for that? Seems rather a blanket statement for what will be a rather complex phenomenon.

Its probably true for, say, base oil stability, but the effect of additives (which are probably a significant quality differentiator) seems likely to be...well...additive.


Except they are all diluted across all of the other basestocks before being added.

To end up equal, they all have to behave linearly with concentration and cumulatively in effect to get back to "1" in every aspect of performance.

I think it's pretty safe to say that's a pretty big ask.
 
Originally Posted By: fdcg27

A '97 Tracer. eh?
That would have the engine known to drop valve seats IIRC.

How many miles on this little beast that you end up with extra oil, which means you apparently don't need to add any?


Yes, I stress about the valve seat issue with every start up. God Forbid it happens.

I'm the second owner, I've put more miles on it than the original owner did lol. He ordered it pretty rarely: a purple Mercury wagon, stick shift, with every option including 4 wheel disc and ABS. He gave me every receipt since day one. The ol' wagon's gonna flip 166K on the way to work in the morning God willing. Here's a pic when I was cleaning up my rear rotors that had gotten a little surface rust on the mounting surface:

 
Originally Posted By: wemay
Living south of the arctic circle, i wouldn't worry one bit.


Even north of the arctic circle, it doesn't matter that much.

As long as the weights have a decent winter rating or the engine is plugged in you can still mix whatever. Will it be ideal for the additive packs? Not on paper at least but in real world....you wouldn't notice a thing.
 
Red bottle oil in a Purple car... I dunno
laugh.gif
 
Originally Posted By: 4WD
Royal Purple ?


that's what I was thinking, but waited for somebody else to say it
laugh.gif


As far as mixing in a 20 year old car with mileage; you bet, any day all day, if that's all I had one hand
smile.gif
 
Right on - purple oil matters - mix one in - always laughed at the "compatibility" disclaimers on synthetic oil ... man, if those "selected" molecules don't set right with the "deplorable" molecules - then ensuing camshaft riots will be justified somehow ...
 
3k changes sure seems wasteful for a vehicle that drives almost exclusively at 65mph. 100 miles a day means changing every 1.5 months and spending $150 a year?

OP should consider a 10k or 15k oil and filter. And the extra quart in a 5 quart jug can be used for top ups. 2 to 3 oil changes a year and maybe $100 a year saved.
 
Originally Posted By: Shannow
Originally Posted By: Ducked
Originally Posted By: UltrafanUK


When you mix oils it does not improve things and the final result will depend on how poor the quality of the worst sinner in the collection of cans was.


Any basis for that? Seems rather a blanket statement for what will be a rather complex phenomenon.

Its probably true for, say, base oil stability, but the effect of additives (which are probably a significant quality differentiator) seems likely to be...well...additive.


Except they are all diluted across all of the other basestocks before being added.

To end up equal, they all have to behave linearly with concentration and cumulatively in effect to get back to "1" in every aspect of performance.

I think it's pretty safe to say that's a pretty big ask.


True (assuming there is no additive commonality). Its a big ask, and not very likely to happen, but it doesn't seem quite as arbitrary a set of assumptions as the statement above.

To take a limit case, if the final results "depend on how poor the quality of the worst sinner" is, if that "sinner" didn't have any additive, that would seem to require the other additives to disappear.

That's more like a conjuring trick than a simplifying assumption.
 
It's not ideal, but you'll be fine with a 3K OCI on a 97'. Personally I'd consider buying something on sale and going to 5K and using the other bottles as top off...
 
1.) Some oil is better than no oil - duh ...

2.) Some clean oil is better than dirty oil, as in real dirty ...

3.) All one oil is "maybe" better than mix-ola ...

Back in the day when I worked lube bays in gas stations, every owner kept a jug (or drum) to drain the last bits from any bottle/can for their own use. All had shop trucks that had been running on this who knows what mix for 100,000 miles at least. All ran fine, engines were smooth and quiet.

Just like being on a trip and having to top up with whatever is available. It always works fine
smile.gif


All these oils are more similar than they are different. MIGHT there be additive clash - maybe ... But it's never been proven or demonstrated to be a problem. And we know there are millions of car owners that pour whatever is at hand into the crankcase and drive on into the sunset
smile.gif
 
Originally Posted By: copcarguy
Would you mix brands of oil?

I certainly would, if the engine is not particularly picky about oil.
That means, not turbo, not DI, not a known sludger, and not of very recent design.
 
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