Does a Turbo diesel engine NEED synthetic oil?

[Redhawk454]

I've heard this a lot, Turbo charged engines "need" synthetic oil to prevent coking of the oil on the bearings in the turbo after you turn the engine off. I always idle 3-4 minutes when I park after highway driving and maybe 2.5 minutes after stop and go driving. The idea is to let oil circulate and carry heat away from the bearings in the turbo and to cool it off.

Some say synthetic oil is necessary for this. idk. Most 15w40 oil is conventional or synthetic blend. There's not a lot of synthetic 15w40 out there, just Amsoil 15w40, Mobil 1 extreme 15w40, T6 15w40 etc. I'm currently running Orielly 15w40 in my Yanmar powered turbo diesel tractor (Deere) because the dealership didn't have any plus 50 II 15w40. Orielly 15w40 meets all the specs for it.

 

[BMWTurboDzl]

Depends on how many hours/miles the oil is in service and sump capacity. Obviously the consumer should trust the recommendations of the manufacturer as a baseline and adjust accordingly if the consumer wishes to operate outside that baseline.

 

[2005jettatdi]

If you look at the higher flash point of synthetic oil, you can see how it would do a better job of protecting your turbo from coking. Of course, you still want to cool the engine and exhaust gasses off after a hard run on the freeway, especially after coming up a long hill.

 

[JavierH19]

No. There are thousands of examples that have made it past 300k with just standard 15w40 as it's pretty stringent stuff. You'll never put enough use on that tractor engine for synthetic to matter. I've seen uoa's of cheap 15w40 being used in diesel ope for a year and it still shows a tbn of 6-8 which is very strong.

 

[k1xv]

IMO, turbocharged commercial diesel engines ran for years before synthetic oil.

But the difference is, these engines ran for long periods, and their operators knew enough to allow everything to cool down before shutting them off.

On the other hand, automotive light to medium duty diesels as used in pickup trucks and some cars/suvs are driven like pleasure cars. Often run fairly hard and suddenly shut down. Some have water cooling of the turbos that keeps flowing after the shut down, and some do not.

I think a good synthetic is a prudent choice, and may be required to keep the exhaust system from self destructing from use.

 

[kschachn]

Yanmar specifies a specification, not a base stock composition.

 

[Zee09]

My diesel tractor calls for 10w30 but I like Citgo 700 available in many flavors .. SS..blend.

https://www.citgolubes.com/products/citgard-700-synthetic-blend-engine-oils

 

[dogememe]

IMO, turbocharged commercial diesel engines ran for years before synthetic oil.

But the difference is, these engines ran for long periods, and their operators knew enough to allow everything to cool down before shutting them off.

On the other hand, automotive light to medium duty diesels as used in pickup trucks and some cars/suvs are driven like pleasure cars. Often run fairly hard and suddenly shut down. Some have water cooling of the turbos that keeps flowing after the shut down, and some do not.

I think a good synthetic is a prudent choice, and may be required to keep the exhaust system from self destructing from use.

Yeah, going along the highway at 55 for hours on end with an operator knowledgeable enough to idle it for a while after is way easier than a random person driving their diesel vehicle in stop and go traffic.

 

[Redhawk454]

Yanmar specifies a specification, not a base stock composition.

The Deere manual has a tiny, tiny section regarding motor oil and it’s based on a temperature chart and nothing more. The owners manuals in the larger john
Deere tractors with John Deere designed and built engines (5000 series and up) require break in oil for the first 100 hours. Those owners manual go more into depth about oil.


Yanmar doesn’t say much about conventional or synthetic. Their oil is either 15w40 or 10w30

 

[kschachn]

I was going by where you said:

I'm currently running Orielly 15w40 in my Yanmar powered turbo diesel tractor (Deere) because the dealership didn't have any plus 50 II 15w40. Orielly 15w40 meets all the specs for it.

 

[Foxtrot08]

Nope. Not needed. I have several fleets that exceed 75,000 mile drain intervals on synthetic blends. Some have pushed out to 90,000 mile drain intervals.

 

[BHopkins]

This is an interesting question for me. I have recently entered the turbo diesel world with the purchase of my motor home. I realize that the use of synthetic motor oils was less common when the Cummins ISC 8.3 was designed and released, back in the late '90's. (In fact, the recommended API category in the engine manual is CE/SG.) But there is no mention of using a synthetic motor oil.

I understand that synthetic motor oils have a much higher burn point. But there is a lot of history of tractor/trailer rigs using dino 15w40. But I am very curious what will be shared on this thread, so I can decide if I need to be upgrading to something like Shell Rotella T6 or Mobil Delvac Extreme.

 

[Shel_B]

IMO, turbocharged commercial diesel engines ran for years before synthetic oil.

But the difference is, these engines ran for long periods, and their operators knew enough to allow everything to cool down before shutting them off.

On the other hand, automotive light to medium duty diesels as used in pickup trucks and some cars/suvs are driven like pleasure cars. Often run fairly hard and suddenly shut down. Some have water cooling of the turbos that keeps flowing after the shut down, and some do not.

I think a good synthetic is a prudent choice, and may be required to keep the exhaust system from self destructing from use.

The large sump capacity of commercial trucks also plays a role.

 

[53' Stude]

The Deere manual has a tiny, tiny section regarding motor oil and it’s based on a temperature chart and nothing more. The owners manuals in the larger john
Deere tractors with John Deere designed and built engines (5000 series and up) require break in oil for the first 100 hours. Those owners manual go more into depth about oil.


Yanmar doesn’t say much about conventional or synthetic. Their oil is either 15w40 or 10w30

 

[totegoat]

Used non-synthetic oil in turboed engines for a long time. Never experienced a turbo failure. They quit recommending extra idling years ago.

 

[dnewton3]

Does a Turbo diesel engine NEED synthetic oil?​

(When you ask a very broad question, you're in for a very broad series of answers.)


What engines "need" are lubes that meet or exceed the OEM specs.
That may or many not be indicative of a lube mandating certain characteristics which can only be met by certain base stocks.

 

[loneryder]

I've heard this a lot, Turbo charged engines "need" synthetic oil to prevent coking of the oil on the bearings in the turbo after you turn the engine off. I always idle 3-4 minutes when I park after highway driving and maybe 2.5 minutes after stop and go driving. The idea is to let oil circulate and carry heat away from the bearings in the turbo and to cool it off.

Some say synthetic oil is necessary for this. idk. Most 15w40 oil is conventional or synthetic blend. There's not a lot of synthetic 15w40 out there, just Amsoil 15w40, Mobil 1 extreme 15w40, T6 15w40 etc. I'm currently running Orielly 15w40 in my Yanmar powered turbo diesel tractor (Deere) because the dealership didn't have any plus 50 II 15w40. Orielly 15w40 meets all the specs for it.

I don’t know of any modern turbo that is not oil and/or water cooled.

 

[BHopkins]

The large sump capacity of commercial trucks also plays a role.

I've wondered if this is also a major factor, in considering how well the temperature of the motor oil is maintained in a large turbo-diesel engine. The oil capacity for the 8.3 ISC in my motorhome is 6.2 gallons. It seems that this has to be a factor.

 

[A_Harman]

Turbodiesels in general do not require synthetic oils because diesel exhaust is hundreds of degrees cooler than gasoline engine exhaust. Diesels run with a lot of excess air, with air-fuel ratios ranging from 70:1 at idle to 23:1 at full power. Consequently, hot shutdown heat soak is very much less of a concern in a diesel, where the EGT rarely exceeds 1250F. Gasoline engine exhaust ranges over 1650F, and modern stoichiometric engines are over 1800F.

 

[Bailes1992]

This is often something I've wondered.

We have a lot of small diesel's in passenger cars over here in the UK and I often pick up HDEO's in bulk. I always make sure to buy synthetic ACEA E9 oils but also look for API S* to they are truly universal.

I currently have 20 litres of Mobil Delvac ESP 15w40. It's advertised as 'synthetic technology'.