Volvo 4.3 oil

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I've been using Delvac 15w40 in my twin 4.3 EFI Volvo Pentas.

The oil pressures are always pegged at 80psi on plane, no matter the engine temperature.

I boat in Michigan, so my ambient boating temperatures range from 50f to 100f throughout the season.

Wouldn't the oil filters go into bypass mode at constant 80psi oil pressure and not filter much of anything? Or am I understanding bypass mode wrong?

This season Rotella T5 10w30 is price drop at Walmart for $16/gallon with a $5 mail in rebate. I bought 3 gallons to do both engines. Ive never used anything but 15w40 in these engines.

Has anybody else ran a HDEO 10w30 in their marine engines?

 

[The_Jeff]

The pressure in your bearings and on your gauge doesn't matter too much with the filter.

The filter bypass is for when the media gets clogged and it lets thick oil by.

However, you probably run in the 3-4500 RPM range and all this flow, even with warm oil, is going to bypass quite a bit, probably.

But they thought this over when engineering the filter, so they hope and expect it will still catch stuff running over the media, and not through.

 

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Originally Posted By: eljefino
The pressure in your bearings and on your gauge doesn't matter too much with the filter.

The filter bypass is for when the media gets clogged and it lets thick oil by.

However, you probably run in the 3-4500 RPM range and all this flow, even with warm oil, is going to bypass quite a bit, probably.

But they thought this over when engineering the filter, so they hope and expect it will still catch stuff running over the media, and not through.


Thanks for the reply.. the reason I ask is both engines have 170 hours. I bought the boat around 90 hours. The starboard engine is always at 80psi, whereas my port will go to 80 and then after a while of cruising rest around 60-70psi. The starboard oil is noticeably darker that the port engine. I just figured the oil filter was in bypass mode.

Again, I dont know much about bypass mode so I wasnt sure if that was the cause. Both engines are original, quiet, dont burn oil, same fuel burn, I dont use one more than the other, etc...

 

[The_Jeff]

Maybe one is running cooler than the other?

 

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Originally Posted By: eljefino
Maybe one is running cooler than the other?


The starboard might run a little cooler... but not much (5 degrees maybe?). The port side is connected to the hot water heater heat exchanger.

 

[car54]

oil bypassing the filter has nothing to do with overall oil pressure, but oil pressure differential across the filter media. If the oil is flowing thru the filter media, it will not bypass, regardless of the pressure. With oil pressure that high, it probably isnt flowing much thru the bearings and you probably don't have any bypassing the filter at all.

There is no good way to know if any oil is bypassing the filter. It's not even worth worrying about. boat and be happy, and do a used oil analysis on both engines to get a better idea of their overall health if you are truly worried about it.