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Using the wrong oil

I have a question and a comment. First the comment. I know first hand that a store (jiffy)had run out of almost all their bulk oil and was still changing oil but they were refilling the cars, and I mean regular passenger cars with 76 Fleet Supreme EC 15/40 oil, you know the kind for diesel engines. Now the question. What kind of damage can that cause to the motor, from older cars to new ones?

Far Less Damage Than Draining The Old Oil And Then Not Refilling At All!

Diesel oils generally just have a lot more detergent in the them to keep the soot in suspension so it will get flushed out with the old oil. Assuming the 15/40 part is OK for your car you should be fine. In fact many oils are good for both diesel and gasoline. When you look at a can of the stuff you will see SAE ratings. The S ratings are for spark ignition (like gasoline) and the C ratings are for compression ignition like diesels.

The only question is does that oil meet the requirements of your car and for that you need to check your car's owner's manual and then the oil.

The above advice is good - but I would just add that this is much to heavy for most any passenger car/light truck engine, most of which will be designed to run on 5/30 or 10/30 or so. I would never leave such an oil in my car in the winter (and would even be happier to get it out in the summer) as its thickness will be under lubricating some crucial areas at times - especially at start up.

totallyh agree, and the additive pkg for oil is not there in the right level. Drain and refill properly at first opportunity

Many Newer Little Cars Now Call For 5w20. That’s A Big Stretch From 15w40.

One time oil change if only kept in there for 3-5k miles AND in a tempered climate…probably nothing. If they keep it in there too much longer or if the temps drop below 20…a LOT of damage could occur.

I’d drain and fill, this is the incorrect (too heavy) oil for your car, and I’d demand a refund from JL.

Yes, I would only recommend 15W40 in the summer or for heavy towing. Starting a car with 15W40 in cold weather without a block heater will starve the valve gear and other critical areas of lubricant for up to a minute, causing very rapid engine wear. A good reason why truckers leave their diesel engines running in cold weather.

And with all the sensors on today’s cars the wrong type of oil, not the wrong grade would not cause any bad codes or sensor malfunctions. Would the computer just compensate.

The computer can’t compensate for too-high oil viscosity, and it might not trip any code.

15-40 is universal fleet oil, rated for gasoline and diesel engines. It’s safe to use in everything from lawn mowers to turbocharged diesels. You are trying to make an issue out of something where there really is no issue. No “engine damage” will result from using this oil in virtually ANY automobile engine. Yes, the viscosity is a little high for small rice motors, but they will all survive non-the-less…

What is the motivation for all the oil questions (not just this one) when the variable is so minute?

People asking if a 5w difference in recommended oil weight and what is in the car will destroy their engine.

The very first answer to the thread (from CSA) sums it up exactly.

Come-on people there is some tolerence in these oil issues.

I always try to get the correct oil (in every way) but using a different viscosity is better than running a quart low. Full and clean is a great start

OP asked a blanket (old to new) question, and, while many cars can handle 15/40 fine, I would immediately change the oil for the correct grade for a new car built to run on 5/20, and JL should pay.

but I would just add that this is much to heavy for most any passenger car/light truck

I totally agree. I tried to convey that idea, but I guess I should have stated it a bit stronger.

I agree that it won’t hurt anything but it is a very good indicator of why one should not trust them.
If they will do this then what other things are they altering/skipping over/modifying or even flat not doing.

My Lincolns don’t have “small rice motors” (they’re V8s), but they do require 5W-20 oil. Use of 15W-40 would quickly result in valve train damage and no telling what else. Warranty would be void too. Times change, and so have engines and engine design.

No “engine damage” will result from using this oil in virtually ANY automobile engine.

Obviously you live in a Southern Climate. That oil could easily DESTROY an engine if it was used in ANY car here in NH this past week. Temps Tuesday and Wednesday morning here were -2. At -2 15w isn’t oil any more…it’s thicker then molasses.

My 4.6 V8 Crown Vic LOVES 15w-40. Ford recommends 5w-20 to get maximum mileage but 15/40 while not ideal, will cause no damage…

Oh,No! another Jiffy lube story.

Who Knows what is best for your vehicle,Jiffy Lube,or the manufacture??
If your car is still under warranty and something happens to the engine for any number of reasons,and the manufacture finds out that you used the wrong oil kiss any warranty repairs good bye.