OK to run 50/50 Full - Semi Synthetic

[Caveman]

Before I posted this and had someone send a cruise missile to NH I searched and went through 4 pages of old oil related posts and couldn't find the answer.

Here's the question - last oil change I went with 0W-40 Yamalube Full Synthetic after using 0w-30 Semi Synthetic for the first 2 oil changes (sled has 3500 miles on it). However, there were a couple times last winter in below 0F temps that it sounded like a "dry start or rough noise" when it first fires up, isn't there in warmer temps and I don't remember being there the previous season running semi-synthetic .

So - seeing that it seems half the riders use semi and the others full synthetic and having 2 quarts of each left over from changes on other sleds, I decided to dump them all in on this change and make a 50/50 Semi - Full Synthetic oil cocktail. It doesn't hurt a car engine so I figured why not. However, before I run it, the dealer said that's a no-no. One has Ester and the other Molly?..and they're not compatible and not a good idea. The Dealer's service mechanics are great..for the few times I've been there, but the Parts counter help I asked are goofy non-experts which is why I'm here. Sorry for the long post on such a silly subject but thought I'd ask for some opinions before I just run it.

 

[Sasquatch]

My answer is a question! When you change your oil there is a bit less then a liter still in the motor, about a liter if you don't change the filter! So if you change from semi to full or full to semi is there a problem and therefore a no no? Ask your dealer! I have never mixed oil half and half but really question what the problem is! He is basically saying the oils are not compatible! First I ever heard of that, if its a problem then Yami would have posted something about it and I can find nothing from them!

To the other part of the post 0-30 or 0-40 both have the same viscosity at cold temps the only difference more or less is when the motor is hot! Starting should be the same!

 

[Teamblue4]

spend $20 and get the correct oil!

 

[YammyRX1]

You can find articles that say there is no problem mixing, and then some say that it's not dangerous but you will lose the benefits of the synthetic, and others that say the additives may react with each other. Bottom line is that it probably won't hurt the motor but it will not improve performance and you may not get all the benefits of the additives.

http://www.valvoline.com/faqs/motor-oil/full-synthetic-motor-oil/

http://chemistry.about.com/od/geochemistry/f/What-Happens-If-You-Mix-Regular-And-Synthetic-Oil.htm

 

[Caveman]

Thanks for the links and suggestions. Can't take a chance with that motor, drained it, replaced with all synthetic and ran it. Kept the other oil for the kids jelopies.

 

[Irv]

Thanks for the links and suggestions. Can't take a chance with that motor, drained it, replaced with all synthetic and ran it. Kept the other oil for the kids jelopies.

There should be zero issues mixing the two oils, especially if both are Yamalube, and like someone already mentioned, how are you suppose to get "ALL" of the previous oil out during an oil change?

I won't give you my opinions on Yamalube, already mentioned numerous times what I think of it, lol

But I will say, after having used Mobil-1 OW-4O for around 5 yrs now, all my starts sound the same, whether it is freezing cold or a little on the warmer side.

 

[Mooseman]

All oils, synthetic, semi-synthetic or dino lube, must be compatible with each other as per API specs so no problems adding one to another. reason being that if you have to add oil, you might not know what's in there already. The only issue is that if you are using synthetic for its pourability/pumpability in cold weather, it may be affected by regular dino lube added to it. Likewise, if you are doing extended oil changes with synthetic, the longevity of the oil will be affected.

I also use Mobil1 0W40 European formula here, no issues.

 

[YammyRX1]

All oils, synthetic, semi-synthetic or dino lube, must be compatible with each other as per API specs so no problems adding one to another. reason being that if you have to add oil, you might not know what's in there already. The only issue is that if you are using synthetic for its pourability/pumpability in cold weather, it may be affected by regular dino lube added to it. Likewise, if you are doing extended oil changes with synthetic, the longevity of the oil will be affected.

I also use Mobil1 0W40 European formula here, no issues.

This will be my first season with the Mobil 1 0W40, I hope it's as good as what I have heard because Yamalube at -25C doesn't sound very good on start up.

 

[maim]

0w30 yamalube semi here and it still starts hard at -40c but it does start! best days to ride as all the other guys cannot get their stuff started. usually see 75% yammys on those days.

mixing motor oil should not hurt it at all. gear lube is another story. that does not mix well at all once over a certain % and i have seen the aftermath.