If you run Mobil 1 5w40 TD,. with virtually no thermal breakdown do you actually need an oil cooler? The idea is to plug the lines at the oil filter instead of replacing the lines.

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1990 350 SDL
Currently: 180,000 miles
Factory rebuilt bottom end rods, bearings and head gasket @ 75,000 in 1997

oil coolers are not focused on increasing the longevity of oil. They improve the longevity of the engine.

By cooling the pistons (in this case), they reduce excessive wear.

removing the oil cooler permanently is not a wise decision if you plan to drive the car regularly and dependably.

It may not be a big issue if its a temporary removal and the driving is done very gently.

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And, if this is for that 'factory rebuilt bottom end' on the engine that is known for bending rods..... don't even think about it. ($.02)

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The oil cooler thermostat in my 78 300SD is not opening up for the oil cooler, and the engine runs hot in anything but cold weather. I agree that you need the oil cooler for the engines sake.

W.

I do not run the cooler on my race engine. However, it only runs for a mile at a time and so far the oil temp has always remained under 175 F or so. I'm NOT, however, recommending this for a street driven car.

BTW, neither would I recommend plugging the cooler lines even if just for a short time. Instead, loop the lines at the oil filter base from inlet to outlet so the flow path remains intact. (BTW, that's also where I installed my oil pressure sender). As well as I was able to trace the oil flow path it seemed like the oil might be circulating thru that path and maybe to critical engine bits - why find out the hard way!!??

Dan

The 350 is in excellent condition. No issues here. My post is related to reading other posting. Just information question

__________________
1990 350 SDL
Currently: 180,000 miles
Factory rebuilt bottom end rods, bearings and head gasket @ 75,000 in 1997

In general, diesels have three paths to shed heat: coolant, oil, exhaust. While your oil may not break down from the higher temp due to a lack of oil cooler, the engine will suffer. The pistons get a shot of oil directed at their underside to absorb & carry off heat from the crown. Keep the cooler, your engine will thank you.