Oil Cooler

I have a 2015 R25SC with the D3-150 engine. My question is, does the oil cooler use raw water to cool the oil or circulating engine coolant?
Trying to plan long term maintenance and looking at servicing the after cooler and engine cooler.
The boat is operated in sea water and not kept on a trailer.

Ralph

The oil cooler is part of the freshwater cooling system. It is a plate cooler. Draining and flushing the engine antifreeze every other year for the preventative maintenance of the D3.

LMRanger said:

I have a 2015 R25SC with the D3-150 engine. My question is, does the oil cooler use raw water to cool the oil or circulating engine coolant?
Trying to plan long term maintenance and looking at servicing the after cooler and engine cooler.
The boat is operated in sea water and not kept on a trailer.

Ralph

Click to expand...

You don’t mention what oil. The transmission oil is cooled via raw water (sea water in your case). In your boat the transmission oil cooler is the first cooler after the raw water strainer and actually serves as a better filter than the sea strainer. It is a good idea to annually check for sea grass build up at the input of the transmission oil cooler. It is a simple check by pulling one raw water hose.

You also mention the aftercooler (aka charge air cooler). Servicing this cooler can be a challenge with the tight space in your boat as access is very difficult even when the turbo is removed. Your shop may suggest the engine has to be pulled to service. It is possible to remove and service the aftercooler by removing the turbo first without pulling the engine but you may have to check to several shops.

Different boat C26. I did remove the after cooler leaving the engine in the boat. Yes it is tight. The Turbo was removed first. I was actually replacing the Turbo because of a failed oil seal. The reason for removing and servicing the after cooler was it was completely oil soaked from the oil seal failure. There are photos of the removal in my albums. There is also a photo of the engine oil cooler hose that was rubbing on the engine stringer. Had I not seen this when I serviced the after cooler it probably would have failed.






When I finished the job I replaced the turbo hose clamps with better clamp for silicone hoses.

BB marine said:

Different boat C26. I did remove the after cooler leaving the engine in the boat. Yes it is tight. The Turbo was removed first. I was actually replacing the Turbo because of a failed oil seal. The reason for removing and servicing the after cooler was it was completely oil soaked from the oil seal failure. There are photos of the removal in my albums. There is also a photo of the engine oil cooler hose that was rubbing on the engine stringer. Had I not seen this when I serviced the after cooler it probably would have failed.

IMG_2170

• BB marine
• Sep 7, 2019

IMG_2163

• BB marine
• Sep 6, 2019

aftercooler contaminated with oil

IMG_2175

• BB marine
• Sep 7, 2019

fullsizeoutput_200

• BB marine
• Sep 7, 2019

hose wore thin from rubbing on the stringer.

fullsizeoutput_1ff

• BB marine
• Sep 7, 2019

oil cooler

IMG_2166

• BB marine
• Sep 6, 2019

Damaged Volvo silicone hose

IMG_2317

• BB marine
• Nov 1, 2019

When I finished the job I replaced the turbo hose clamps with better clamp for silicone hoses.

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Yep. Same experience here with the failed turbo oil seal. As you may recall I previously described here in Tugnuts having a slow rise in engine temperature and loss of horsepower over the years we’ve had the boat. The power loss even led me to re-pitch the prop. After checking everything else possible I finally zero’d in on the aftercooler and asked the shop to clean it. They initially said they’d have to pull the engine. I asked that they pull the turbo first with the engine in place and then see if they could see any issue with the cooler from there. Then we could decide what to do. The next day their tech had the cooler on the bench. I guess nobody told him the engine would have to be pulled! Ha! The cooler was completely sludged up. I don’t know yet if this is cause of my temp rise and power loss because I’m still waiting for a new turbo from Sweden. I hopeful was but the worked needed to be done in any case. Interestingly, my turbo never exhibited any sign of problems and I had no noticeable indication of the oil leak.