Changing from synthetic oil question

[Gerry P.]

I'm currently using Mobile 1 CJ-4 in my '57 and after reading the various discussions on oil in this forum and Duke's comments, it appears I'm not gaining much if any by using the more expensive oil. As a result, I'm inclined to go back to the cheaper non-synthetic oil. The clerk at the local auto parts store commented that to change back to regular oil, the engine should be flushed to rid it of any residual synthetic oil as the synthetic does not mix well with regular oil. Does anyone have any comments on this and if a flush is necessary, what is the procedure?
Regards,
Gerry

[Patrick H.]

Re: Changing from synthetic oil question

I'm currently using Mobile 1 CJ-4 in my '57 and after reading the various discussions on oil in this forum and Duke's comments, it appears I'm not gaining much if any by using the more expensive oil. As a result, I'm inclined to go back to the cheaper non-synthetic oil. The clerk at the local auto parts store commented that to change back to regular oil, the engine should be flushed to rid it of any residual synthetic oil as the synthetic does not mix well with regular oil. Does anyone have any comments on this and if a flush is necessary, what is the procedure?
Regards,
Gerry

You really believe the guy behind the counter?
Really?




Since the majority of synthetic oils are now made from the same base stock as dino oils, the difference between them is minimal. Even if there were I would not think twice about it.

Just do it.
Dump in your 5 quarts at your next oil change and forget about it.

Patrick

[Larry M.]

Re: Changing from synthetic oil question

Agree with Pat. Can't believe (well.....almost can't believe) someone would make that statement.

Drain the old oil, replace the filter, add your new oil, and go.

Larry

[Duke W.]

Re: Changing from synthetic oil question

I'm currently using Mobile 1 CJ-4 in my '57 and after reading the various discussions on oil in this forum and Duke's comments, it appears I'm not gaining much if any by using the more expensive oil. As a result, I'm inclined to go back to the cheaper non-synthetic oil. The clerk at the local auto parts store commented that to change back to regular oil, the engine should be flushed to rid it of any residual synthetic oil as the synthetic does not mix well with regular oil. Does anyone have any comments on this and if a flush is necessary, what is the procedure?
Regards,
Gerry

Your product description is incomplete, but assume you are refering to Mobil Delvac 1 ESP 5W-40 (CJ-4).

5W-40 "synthetics" offer no advantages over less expensive 15W-40 CJ-4s unless you cold start the car below 15 degrees F on a regular basis or run 10K miles between annual oil changes.

As far as the clerk is concerned, his comments are why he is a ten-buck-an-hour retail clerk rather than a $40/hour engineer in the auto or petroleum industries.

All conventional and "synthetic" oils are compatible.

Duke

[Gerry P.]

Re: Changing from synthetic oil question

Thanks all for the replies. Duke, I was using the Mobile 1 5W40 "Turbo Diesel Truck" CJ-4/CI-4Plus.
Gerry

[Duke W.]

Re: Changing from synthetic oil question

It's tough to keep up with all the brand variations. That's why I recommend oil selection on the basis of API service category and viscosity, only.

The brand is immaterial. Pay no attention to brand. Any 5W-40 C-category oil can be considered "synthetic", so my above arguments apply.

Any 15W-40 C-category oil is likely more than adequate for your needs. I just buy it on price - whatever 15W-40 C-category is least expensive when I shop for oil.

Right now the Walmart SuperTech house brand 15W-40 CI-4 appears to be the best everyday value, unless one of the national brands has a rebate offer going.

Duke