Is Synthetic Oil Safe For All Motors?

[jimainiac]

I thought it was always an improvement to use synthetic oil in any motor, diesel or gas. My brother-in-law has a crane for loading and unloading log trucks, which he bought as a demonstrator a couple of years ago. He likes to take good care of his equipment, so he's been using synthetic motor oil. He just lost the camshaft in the motor, and he said the dealer told him he shouldn't have been using synthetic oil. That sure doesn't make any sense to me, so I thought I'd throw this question out there. Are there instances where it isn't appropriate to use synthetic oil?

 

[Heywood Jannockitov]

There may be situations where you have a combined engine sump/transmission that shares lubricating oil. My Bombardier Traxter XL500 ATV owner's manual does not recommend the use of fully synthetic oil in the engine/tranny sump. Probably affects ability to shift gears, which is done electro-hydraulicly (I think)

 

[RWEST]

A lubricant is a lubricant. As long as it's the proper weight and grade for the application, there's no reason a synthetic will not protect at least at the same level as a non-synthetic.

It's possible the oil he used wasn't rated for the application. Losing a cam has become more prevalent with the advent of oils with lower zinc/phosphorous levels, as has been discussed on just about every forum involving internal combustion.

 

[WTA]

My tractor dealer here tried to tell me I shouldn't be using red diesel too the first time my NEW tractor died. Some shops will try to use any excuse they can to cover up their own incompetence. Or known problems that they don't want getting out.

The only engine I am aware of that you will have a hard time finding the proper synthetic oil for is the Ford Powerstrokes. Mobil-1 did have one with the proper additives for a while but they don't now. Rotella did too but I sure can't find that one anymore either. I'm having to use regular rotella again. It's because of the anti foaming additive that most synthetic diesel oils do not have. I've spent a lot of time looking too. The engine oil using hydraulically activated fuel system on these engines has to have the proper oil if you want it to last very long. I've replaced a lot of high pressure oil pumps on them because the owners were using really good synthetic oil but it didn't have the right additive package. Navistar makes the additive you can add yourself to any oil but most people don't know about it.

 

[kenmac]

Are there instances where it isn't appropriate to use synthetic oil?

I don't think I would use it (or change over to) synthetic in a high mileage engine. You may notice oil leaks

 

[DieselPower]

Somehow I doubt the failure was caused by a difference in oil base stock. Unfortunately mechanics are often not the best informed when it comes to lubricants. They are prone to grape vine gossip and misinformation just like everyone else.

Are there any situations where a synthetic shouldn't be used. Yes, a couple come to mind but very few. Usually only where the oil is used in a common sump system and there is concern that the low coefficient of traction of a synthetic base stock may adversley effect friction material gripping performance in things like wet clutch disc systems. Unless a owners manual specifically states not to use a synthetic based oil don't worry about it.

 

[vsteel]

Somehow I doubt the failure was caused by a difference in oil base stock. Unfortunately mechanics are often not the best informed when it comes to lubricants. They are prone to grape vine gossip and misinformation just like everyone else.

Are there any situations where a synthetic shouldn't be used. Yes, a couple come to mind but very few. Usually only where the oil is used in a common sump system and there is concern that the low coefficient of traction of a synthetic base stock may adversley effect friction material gripping performance in things like wet clutch disc systems. Unless a owners manual specifically states not to use a synthetic based oil don't worry about it.

1. I think that the grapevine issue has a lot to do with how old the information is vs miss information. In my personal experience, a lot of the mechanics tout information that is 30 to 40 years old and hasn't applied for the last decade or so.

2. You came up with the only thing that I could think of for not using synthetic. Though all of the times that I could see you wouldn't use synthetic in those applications, you are not supposed to use regular motor oil either. Motorcycles come to mind, its the anti friction additives they have which can cause issues with a wet clutch, and those same anti friction additives would be found in both dino oil as well as synthetic. Though in reality I know of only one motorcycle that had issues and would burn out clutches because of using non motorcycle specific oil.

 

[thump186]

A lubricant is a lubricant. As long as it's the proper weight and grade for the application, there's no reason a synthetic will not protect at least at the same level as a non-synthetic.

This is not really true. Synthetic oils are generally thinner then organic oils but because of their additive packages they meet the requirements of goverment standards. Oils such as Mobil1 and syntec contain organic oil base stock. Oils such as Amsoil, Red line and royal purple are actually true synthetics which accounts for their higher prices. For more info Bob Is The Oil Guy is a great site with alot of interesting data.

 

[kenmac]

When did mobil 1 change ? Last time I checked they were PAO just like amsoil & some others

 

[RWEST]

A lubricant is a lubricant. As long as it's the proper weight and grade for the application, there's no reason a synthetic will not protect at least at the same level as a non-synthetic.

This is not really true.

Which part?