Is there really a problem to go from mineral to synthetic, or 15w40 to 10w30?

[freedomlives]

I went to an oil store today to get 10w30 oil for my Iseki TS3510, as its been over a year since I've had it, and the hour meter is broke, but guessing I've used it for 100 hours, which is the oil change interval in the manual.
The manual (from the 1980s) calls for 10w30. The guy at the store said he can only get it in 20liter containers, when I need 7. I asked if 5w30 would work, and he said its not good to go from semi-synth to synth, and then asked what's in there now.

It has 15w40 in there now, that the Poles who imported it put in, along with 80w90 gear oil that turns out to be too thin. The guy at the store said that if its got 15w40, its fine, and better not to go then to 10w30 because any deposits will get loosened up or something. Honestly, I was a bit tired, and just went with his advice, so I've got Shell Rimula 15w40, as well as the proper 85w140 gear oil for the transmission.

Now I'm just rethinking it though. Obviously, the oil will be thicker 40 weight when it gets up to operating temperature instead of 30 weight, and perhaps the last year of 15w40 has been wearing on the engine?

The engine is an Isuzu 3ab1.

Or am I putting too much worry into this?

 

[CalG]

I went to an oil store today to get 10w30 oil for my Iseki TS3510, as its been over a year since I've had it, and the hour meter is broke, but guessing I've used it for 100 hours, which is the oil change interval in the manual.
The manual (from the 1980s) calls for 10w30. The guy at the store said he can only get it in 20liter containers, when I need 7. I asked if 5w30 would work, and he said its not good to go from semi-synth to synth, and then asked what's in there now.

It has 15w40 in there now, that the Poles who imported it put in, along with 80w90 gear oil that turns out to be too thin. The guy at the store said that if its got 15w40, its fine, and better not to go then to 10w30 because any deposits will get loosened up or something. Honestly, I was a bit tired, and just went with his advice, so I've got Shell Rimula 15w40, as well as the proper 85w140 gear oil for the transmission.

Now I'm just rethinking it though. Obviously, the oil will be thicker 40 weight when it gets up to operating temperature instead of 30 weight, and perhaps the last year of 15w40 has been wearing on the engine?

The engine is an Isuzu 3ab1.

Or am I putting too much worry into this?

Yes, too much worry.

Mix and match all you want. just keep the oil clean.

Your ambient temperature determines what weight oil to use, and there is a LOT of overlap.

 

[freedomlives]

Thanks! Well, looking at a chart of temperatures, 15W40 looks fine for most of the year, except severe winters. Not planning on using the tractor during the dead of this coming winter, so will pour in that 15w40.

 

[Ortimber]

I think the parts guy was confused.

There is such a thing as non detergent oil, something like SAE 30. If your tractor had a non detergent oil in it for 30-40 years, there’s a chance some sludge could be present inside your engine. Adding a modern detergent based oil (which I think most are) could theoretically start breaking loose old sludge/deposits. Would I be concerned? Not really.

 

[freedomlives]

I think the parts guy was confused.

If only he were just a parts guy. But instead, it was at a shop selling just lubricants! Anyway, reminds me again why I normally prefer to just buy things online, but I'd kept forgetting to go eshoping in the evenings, so was in town and dropped by there.

 

[RalphVa]

I worked in the lube oil industry for 31 years. Lots of ignorant people out there about oil. I've switched from conventional oil to synthetic on all kinds of engines and have switched from xw40 to xw30 oil in a diesel. No problems whatsoever. On an old Gravely that had been using oil, it plain quit using oil after about the 2nd or 3rd change using synthetic oil. Never ever had problems with engines suddenly start using oil when switching to synthetic.

You can use a 0w30 or 5w30, for instance, in a diesel tractor engine anywhere in the US all year round. Those upper charts showing oil grade by temperature just don't make sense for water cooled engines. I suspect they were done for air cooled engines. The upper temp in a water cooled engine is set by your thermostat, which is typically 180-190 F. The oil temperature would be slightly above this. This is why engine oils are rated for 212 F or 100 C.

You can even use a gasoline engine rated oil in a diesel engine, too. You just need to change it more frequently. Main difference is a bit different or more detergent to hold the blowby soot in suspension in a diesel engine oil. So, if you find your diesel engine needs oil and all you have is a quart/liter of gas engine oil, use it.

I'd never use a 15w40 oil. Just does not make sense. Why? It will not get picked up by the oil pump as quick as a 0w or 5w or 10w oil on startup. You valve train will just starve for oil in the meantime.

By comparison, gear oils are rated for 100 F because this is about their typical maximum operating temperature.

Ralph

 

[ericm979]

Some early synthetic oils did not mix well with conventional oils. That was many decades ago but the idea persists.

 

[California]

I worked in the lube oil industry for 31 years. ...

You can use a 0w30 or 5w30, for instance, in a diesel tractor engine anywhere in the US all year round.

You can even use a gasoline engine rated oil in a diesel engine, too. You just need to change it more frequently. Main difference is a bit different or more detergent to hold the blowby soot in suspension in a diesel engine oil. So, if you find your diesel engine needs oil and all you have is a quart/liter of gas engine oil, use it.

That makes sense.



Here's a question on the inverse: per this Deere publication on Hy-Gard UTF
PMB Product: ,

"Hy-Gard oil can be used in most applications calling for 10W-30 or 5W-30 engine oil for transmission and hydraulic oils. Note: Hy-Gard should be used in all applications calling for JDM J20C."

After reading that, I wonder if 5w30 gas oil or 15w40 diesel oil are suitable to top-up the hydraulic reservoir on my 40 year old backhoe (that is only operated in mild climate). The backhoe manual says J20C oil should be used. J20C-equivalent UTF is what I've always put in it but I'm more likely to have engine oil on hand when I notice it needs topping up. Any comments?

 

[CalG]

Engine motor oils don't handle moister the way hydraulic fluid does. It's all in the additive package for each.

 

[California]

... I wonder if 5w30 gas oil or 15w40 diesel oil are suitable to top-up my 40 year old backhoe (that is only operated in mild climate). The backhoe manual says J20C oil should be used. J20C-equivalent UTF is what I've always put in it but I'm more likely to have engine oil on hand when I notice it needs topping up. Any comments?

Update! I found a Operation Manual for a near-identical backhoe made by the same company (ARPS).

"Fill with SAE 10w40 engine oil with API "SD" classification in Northern climates.
Fill with SAE 40 engine oil with API "SD" classification in Southern climates.
Change oil every 200 hours or more often if necessary."

Hmmm. Seems like the only significant question is if motor oil and UTF will blend ok if mixed. While either, separately, seems sufficient.