Oil choice for towing with an old Mercedes N/A diesel

[OM605]

Just bought a 1995 Mercedes W202 C250 (2.5 inline 5, 20 valve) that is a beater to be honest but i frequently have to tow a trailer and from experience with other cars with similar engines, i'll have to drive with a lead foot and often drop a gear on the highway to keep up with traffic. The engine will probably run a little hotter and fuel consumption should increase by at least 30%. The usual choice is anything from a 5W40 to a 15W40 but should i up the viscosity to a xW50?

 

[turboseize]

It's an old Mercedes Diesel, make sure it has oil in the sump and it will last.
I'd put any xw-40 in it. If it has some MB cert (229.1, 229.3, or the commercial 228.1, 228.3), even better*.

Does the w202 still have the oil pressure gauge? As long as you have full oil pressure under load and at least 1 bar at idle when hot, no need for higher viscosities.

*You won't see 229.5 on any 15w-40 or 10w-40, because these viscosities cannot meet the fuel savings requirement. You nee 5w-40 or ow-40 for that.

 

[bullwinkle]

How many kg is the trailer, and how much frontal area? Think I would be more concerned with transmission temps myself.

 

[RooflessVW]

My Mercedes of the same vintage did ok on Rotella but if I had one now (in the US) I'd use Mystik 15W-50

 

[CleanSump]

No DPF so you're free to use any diesel oil of choice. I ran my '92 300D 2.5 Turbo to 348k miles on Amsoil 10W-30 Heavy Duty Diesel and Marine oil. 10k mile OCIs, which was twice the book. Didn't have to add a drop of oil between oil changes. Body was starting to rust and plastic stuff was cracking, but engine was primo.

 

[OM605]

Does the w202 still have the oil pressure gauge? As long as you have full oil pressure under load and at least 1 bar at idle when hot, no need for higher viscosities.

Unlike the W124 it doesn't have the oil pressure gauge.

How many kg is the trailer, and how much frontal area? Think I would be more concerned with transmission temps myself.

500kg total, i think. It has a manual transmission.

 

[Oro_O]

Mild maritime climate like Brittany, I'd think 15w-40 would do nicely.

 

[OM605]

Would you spend a little more on HDEO or a PCMO A3/B4 MB approved 15W40 would do just fine? The car is a beater but it drives very well and is reliable. With the prices of vehicles being what they are nowadays, i plan to keep it for a while as a tool.

 

[Bailes1992]

That's a tiny trailer! I'd just pick any *w40 or *w50 A3/B4 oil and be done with it. It really won't care.

I tow a 1500kg caravan with a tiny 1.5 3 cylinder diesel engine in a Vauxhall Insignia. I use a Dexos 2 oil (engine specifies a Dexos D oil). Engine oil pressures and temperatures are just fine. Hotter than usual, but nothing that alarms me.

 

[OM605]

Ok, i wont change anything then. The cheap A3/B4 15W40 will do just fine, maybe i'll cut the OCI a bit.