# What happens if you mix 10w-30 with 10w-40?



## bczoom

We have a beater car that burns about 1 qt every 500 miles.
I've been running 10w-30 but I ran out.  I'm looking at a shelf full of 10w-40 that has no use.
What would happen if I started topping off with 10w-40?
BTW - The full oil change is an option but a bit of a bugger on this car (and I would just go out and buy more 10w-30 before doing the change).


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## Spiffy1

I've done it; can't say I noticed any effects either positive or negative.

If it's burning that much, I would go to the 10-40 in the first place, unless cold weather starts are giving you trouble.


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## California

bczoom said:
			
		

> We have a beater car that burns about 1 qt every 500 miles.


That thing is a perfect candidate to use up all the miscellaneous oil you have around. Just pour in whatever you have. 

I wouldn't worry about increasing wear in the engine, it's already damaged to the extent that oil grade won't make any discernable difference. Quality oil will preserve an engine for the future but in this case the distant future is irrelevant.

And with that high consumption it is pointless to change the oil more than annually - it's already getting five quarts of fresh oil every 2500 miles!

Been there done that.


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## Junkman

When you start to run out of new oil, start to recycle the old stuff.  If it is burnign that much, you won't have to worry about any contaminants causing problems other than the enviormental ones.  I had a car like that back in the 1960's and put Gulf Saphire Oil in when I couldn't find the recycled stuff in the stations.  Recycled oil that had been re refined used to be a big business in the 1960's.  Then the cost of rerefining old oil got too expensive and it seems to have dried up.  Safety Kleen sell a rerefined oil still.  The product line is called America's Choice.....


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## thcri RIP

Back many moons ago I had a friend that had an old "egg beater" we called them.  He use to come into the gas station I worked at and go over to the used oil bin and fill up his car.  He would fill his gas tank up every other oil fill.  I just can't imagine what he put in there since just about everything was dumped in that bin.

I don't think you would hurt it all but may be even help it with the heavier oil as far as burning.

murph


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## DAP

Some might say you get 10W35.


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## humor_me

bczoom said:
			
		

> *What happens if you mix 10w-30 with 10w-40?*


 

MMMMMM, 10W-*35*


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## JimR

Yup, That was what I was going to say too. 10-35w it is. I always run 10-40 year round.


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## daedong

How can you still be allowed to drive this car. Here they would defect it and probably try and charge you for enviromental destruction


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## BoneheadNW

daedong said:
			
		

> How can you still be allowed to drive this car. Here they would defect it and probably try and charge you for enviromental destruction


Vin-This is the good ole US of A! Who gives a crap about the environment? If we don't destroy it, someone else (like the Chinese) will!
Bone


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## daedong

http://www.tceq.state.tx.us/implementation/air/mobilesource/vetech/smokingvehicles.html 

http://www.txdps.state.tx.us/director_staff/public_information/pr082301.htm   (HB2124)
http://www.dmvnv.com/emission_svor.htm#News 
  HA, it does happen


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