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Discussion Starter · #1 ·
I accidently bought Mobil 1 10W30 a couple of months ago and used two quarts because when I first did the change over, the car got hungry and began eating it. Seems like the car is not consuming any more and now I have 4 quarts of oil that is too thick ... so, can I just "thin it out" by adding 6-8 quarts of 0W30 to the mix? If anyone knows a ratio, that would great! Thanks!
 
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You can add it, but it's generally not a good idea. The two oils won't exactly mix. They'll just flow past each other. When I used to work at Autozone I had to call Mobil once for a similar situation and they told me you can mix organic and synthetic oils, but not different viscosities.
 

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Discussion Starter · #4 ·
Yes it can ... higher viscocity oils flow slower than lower viscosity oils, therefore, 5W30 will flow faster than 10W30 and 0W30 will flow faster than 5W30. So, if you engine is designed with very tight tolerances, like most modern engines, a lower viscosity oil is required to properly flow throught these tight areas. Otherwise, you run the risk of clogging and oil starvation ... unlikely, but possible. Someone correct me if I am wrong, but that is my understanding.
 
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Mixing those Mobil 1 grades will not harm your engine, but who knows what the actual rating will be.

Mobil 1 10w-30 is fine in the Cougar as a replacement for 5w-30, when used in the summer or the Southern states.



<< No, only 1999-2000 ... 2001's are a "new" engine with a slightly different displacement and tighter clearances = 5W20 >>



Ford did not change the engines for all vehicles in 2001. Shipped new from the factory, 5w-20 was used and is recommend as replacement. However, there is a TSB that makes the use of 5w-20 retroactive back to most 1996 model year cars. I've read it and is supposed to be to increase fuel economy.

Stick to 5w-20 or 5w-30 and you'll be fine in any of the newer Ford vehicles.
 

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99-00 Manufacturer recommends 5w30, 01 is 5w20. You don't necesarily have to run out and change your oil, but on your next oil change, use 5 w 30.
 
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Another factor that can effect the performance of your oil is under the hood and outside air tempratures. The manufacturer sets a general guideline as to what viscosity oil you should use; however, the climate you live in actually determines the type of oil you should use. For example: If you live in an area where the avg temp is about 90, then you should use 10w40 or 20w50, but if you live in an area where the average temp is about 40 or 50, then you would use 5w30. 0wX is for extremely low tempratures and has an operating range of about -54 to about 50 or 60 degrees fahrenheit so I wouldn't use it unless you live in sub zero climates.
 
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By the way the oil capacity on the cougar is 5 qts so adding that much oil is way overkill. Trying to add 6-8 qts of anything is gonna kill your car.
 

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Discussion Starter · #13 ·
Yes, I know the capacity, what I as getting at there was the proper ratio to bring the 10W30 down to 5W30 using 0W30 as the dilutant. I have 4 quarts of 10W30 left ... how many quarts of 0W30 would be required to bring it all down to 5W30 ... that was the question. If the ratio is 2:1, then I would need 8 quarts of 0W30 to dilute my 10W30 to 5W30 ... make sense? I ask because I saw this and it peaked my curiosity since I have 4 quarts of 10W30 collecting dust:

Engine - Mobil1/Motorcraft Oil Change Kit from ZX2Racing
 

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All the Ford and Mercury dealer I've been to in SoCal use 10w30 or 10w40. 5w30 is not good for 80+F temps which is almost year-round in LA.
 

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Discussion Starter · #17 ·
I think that FORD invented 5W20
Seriously though ... do the other big two use it? What about european makers? As far as I know, only FORD requires the stuff. I just think that it is another scare tactic to force new buyers and easily intimidated owners into getting their oil changed at the dealerships. Why??? Because if your engine fails and they can prove that you used 5W30, they would probably void your warranty and then inform you that your new 2001's replacement engine will cost about $4,000 parts/labor
 
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Well, I don't know what that place was selling, but I'm almost positive you can't mix different viscosities. Bottom line is, it's your car. If you want to try that's up to you, but I wouldn't recommend it.
 
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Trevor,

Just use whatever the dealer puts in when you get an oil change.


My dealer used 10w30, so that's what I use. I may use 5w30 in the winter, but in the summer 10w30 works a lot better.

That way if they try to void your warranty, you can just ask the service department what they use.
And show them your previous work order and shove it up their arse.


Paul
 
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