Engine oil changes: hot or cold?

I will ask and look into this

Thanks for your insight


Edwin

Changing cold oil leaves much of the dirt in the oil pan and passages. I've seen oil pans that only held 1/3 of the oil because of particle buildup. The owner was oblivious.
I have a centrifuge and plumbed my engines to drain via a gear pump. Occasionally I drain the engine oil after running and centrifuge it. My plan is to greatly extend the engine life. When I have the oil tested, it comes back as almost new oil. I haven't actually changed oil in 5 years.

edwmama said:

I will ask and look into this

Thanks for your insight


Edwin

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Take it to a shop and have them clean it and pressure test it.

Change over to single viscosity oil if you now use multi weight.

If the oil burn expense is still too high a Viscosity thickner like Howes (at a truck stop) might help.

My guess would be the low power operation in the past may have stuck the oil scraper ring. If so lots of high power use with an immediate hot oil change might help.

It takes both heat and time for the detergents you paid for in the oil to work, so give the engine both.

The most modern oils have far better detergents to make up for the built in inefficiencies for the Air Police so a higher grade of detergent oil might help.

A bunch of oil changes back to back (25hours) might cost as much as just dumping in a quart every so often?

If the past light loading burnished the cylinder bores a compression check will show it.

Lepke said:

Changing cold oil leaves much of the dirt in the oil pan and passages. I've seen oil pans that only held 1/3 of the oil because of particle buildup. The owner was oblivious.
I have a centrifuge and plumbed my engines to drain via a gear pump. Occasionally I drain the engine oil after running and centrifuge it. My plan is to greatly extend the engine life. When I have the oil tested, it comes back as almost new oil. I haven't actually changed oil in 5 years.

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I read some posts on RV forums by guys running big diesels tons of miles that take the same approach. They do an oil test every 5k-7.5k miles, and only change oil when the test indicates it's required. Some engines take 40+qts of oil, and if you run a lot of miles (hours for us) that expense can add up quickly.

Depending on installation level engines may use oil until they get to the proper level for the installation angle. Dip sticks are not always calibrated properly for the install and factory capacity is for a flat install. You may want to try letting the oil go down a bit and see if it continues to go lower or stops using at that level.

OIL does not wear out , but the additive package does get consumed.

It is there for a reason.

SeaFoam may unstick the rings.

I don't see how anybody can justify changing oil cold. Just lazy perhaps. Like Al Johnson says .. Hot Hot Hot.

Eric try wrestling a 1 quart big hot oil filter from the outside of an engine and you may reconsider.

I pump mine out hot after an extended cruise as I feel it's more likely to have any particulate suspend in the oil and it's easier on the pump. Change the filter the next day when it's cool and pour in the new oil.

Ted

bayview said:

Depending on installation level engines may use oil until they get to the proper level for the installation angle. Dip sticks are not always calibrated properly for the install and factory capacity is for a flat install. You may want to try letting the oil go down a bit and see if it continues to go lower or stops using at that level.

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Bingo!!! I would try this. I even have an old aircooled Porsche 911 that does this. If I keep trying to fill it to the FULL mark it will keep burning the oil. But if I leave it about a quart low, it will stay there. My starboard Cummins does the same thing. It has the factory dipstick. My port engine has a remote calibrated dipstick.

I pump out my engine oil into two war surplus gas cans and tote it off to our yacht club maintenance yard where they have a 55 gallon used oil collection drum. They will also collect the used filters and will exchange used oil absorbent pads for new ones.

bayview said:

Eric try wrestling a 1 quart big hot oil filter from the outside of an engine and you may reconsider.

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O C Diver said:

I pump mine out hot after an extended cruise as I feel it's more likely to have any particulate suspend in the oil and it's easier on the pump. Change the filter the next day when it's cool and pour in the new oil.

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Yep, me too. As I said in post #9, I pump out oil while hot, then do filter changes and refills the next day. No way I'm wrestling with a big oil filter -- our port side filter is already awkward to remove, anyway -- while it's hot.

-Chris

Older Perkins can be really fickle about their oil.

I have twin 6.354 na's. I was burning oil, about 1 qt per 8 hrs at 2400 rpm's on each engine, since brand new. The local yard suggested switching from single weight (30W) to multi weight (10 -30W) and the oil use actually went up.
I continued to run it on 10-30W for two seasons and nothing changed.

I switched back to single weight and was back to 1 qt per 8 hrs.

I did notice that if I ran a little slower, oil use went down. At 2250 RPM's oil use was nearly zero. Only explanation anyone could offer, was that is "the sweet spot for those engines in that boat."

So use a single weight oil and experiment with your engine speed and maybe you can find the "sweet spot" for your engines.

Larry: Try lower level. The crank may be bashing the oil. Sweet spot = baloney. Even if the install is flat some boats run at an angle at speed.

chris: I use a nail to punch a hole and drain the filters into a bucket. Some tape or a metal screw will plug the hole so you avoid drips. An empty big filter is much easier to deal with.

Only once did I try the plastic bag routine. Now I know what wrestling a greased pig must be like.

Edelweiss said:

Older Perkins can be really fickle about their oil.

I have twin 6.354 na's. I was burning oil, about 1 qt per 8 hrs at 2400 rpm's on each engine, since brand new. The local yard suggested switching from single weight (30W) to multi weight (10 -30W) and the oil use actually went up.
I continued to run it on 10-30W for two seasons and nothing changed.

I switched back to single weight and was back to 1 qt per 8 hrs.

I did notice that if I ran a little slower, oil use went down. At 2250 RPM's oil use was nearly zero. Only explanation anyone could offer, was that is "the sweet spot for those engines in that boat."

So use a single weight oil and experiment with your engine speed and maybe you can find the "sweet spot" for your engines.

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I would think running those engines at 2400rpm would be running them a bit hard...no???

bayview said:

Eric try wrestling a 1 quart big hot oil filter from the outside of an engine and you may reconsider.

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Bayview,
No. I'd leave the oil in the filter until it cooled but pump the hot oil out of the engine as soon as possible.
My pump is a built in affair and I pump into light plastic gallon containers like have distilled water in them at the store. I even keep the engine running while I lift the hatches. Usta wonder if the plastic would fail from the hot oil but hasn't happened. But once you get the oil out of the crankcase all the rest can wait till later.

I do not have this problem at the moment since we are in between boats now. I agree that it is best to pump out the oil while it is hot. I was wondering if anyone has an oil recovery tank on-board, that can be pumped out at a later time. If so, is there any places that will come to your boat and pump out your used oil? If one had a system that had two tanks, (one for new oil and one for used oil), and a pump system to pump out the old oil to the recovery tank, then pump in the new oil into the engines. this would sure be a labor saving setup.

FF said:

Detergent keeps the big crud in suspension so the oil filter can grab it.

The fine stuff that passes the filter still requires removal for longest engine life.

A long 5-8+ hour run allows the detergent to re grab the fine stuff stuck to the sides and bottom of the oil pan and get it back in circulation.

This happens with every long engine run , weather you are changing the oil or not.

"Best Practice" would seem to remove it every time the oil is changed.

Or use a centrifugal bypass filter system and catch it as its formed.

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I don't mean to drift the thread too much, but to your comments above, is that the reason why the Gulf Coast oil filters (long thread cellulose) are touted as being so advantageous? These passive filters seem more practical than a powered centrifugal unit on a typical small trawler.

Baker said:

I would think running those engines at 2400rpm would be running them a bit hard...no???

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No, per the manufacture recommendations, it depends on the setup.
The 6.354m "NA's" 130 hp, have a max rpm of 2800 rpm and cruise of 2400 rpm.

Many of the T6.354m "TA's", 185 hp, have a max rpm of 2400 rpm and cruise of 2250 rpm.

PS: If you open the pan inspection port on a 6.354m engine, the rotation of the crankshaft counter weights and rod journals are well above the pan oil level. And running the engine a quart low didn't work either, it would continue right off the end of the dipstick.

QUOTE from edwmama`s post about his excess oil consumption:
"After a 4 hrs trip to Catalina island, (from Marina del Rey ) a mere 28 nautical
Miles away, my engine oil is LOW and requires a top off 1 to 1.5 quarts of oil!
ITS BURNING OIL at much higher rpm
The engine runs smoothly, no overheating no black or blue smoke, good sound..."
I do see a slight white fog coming out of the exhaust but that may Be from the coldness of the water and the fact the exhaust spends 1/3 of time Underwater while cruising..."

FF and others, the absence of burnt oil smoke led me thinking oil was being lost not burnt. Coupled with the fact his HX was in bad shape, I homed in on the oil cooler. Can you burn that much oil that fast, with no smoke?

I agree Bruce but he dosn't have a bilge full of oid black oil. It seems if he did he'd probably have noticed it. But oil leaking into the salt water part of the cooling system would just go on out the exhaust. Perhaps he should check the oil cooler. Engine oil cooler if it is fed sea water.

I would think engine oil escaping through the cooler would leave a pretty good sheen on shutdown out the exhaust.

Motor oil sheen usually is noticeably different than a diesel sheen.

My boatyard doesn't allow its mechanics to work around hot engines. I'd suggest "warm" if you're doing it.

So mechs can't work on a running engine?

psneeld said:

So mechs can't work on a running engine?

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Don't think I could either. Unless I've had 3 double espressos, after that and I could thread a sewing machine while it's running.

bayview said:

chris: I use a nail to punch a hole and drain the filters into a bucket. Some tape or a metal screw will plug the hole so you avoid drips. An empty big filter is much easier to deal with.

Only once did I try the plastic bag routine. Now I know what wrestling a greased pig must be like.

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Yeah, I meant to try the drain hole thing... but worked out that a big zip loc bag works well enough on our port filter. "Greased pig" is what happens if there's a slip-up, but mostly the big-a$$ bags are big enough so it's all manageable. And I'd probably need to use a bag anyway, even if the filter were mostly drained in advance.

I use a bag on the starboard filter, too, but that's very straightforward.

Usually the result is that the bag/filter goes into the bucket, and the bucket itself never even gets oily.

-Chris

ranger42c said:

Yeah, I meant to try the drain hole thing... but worked out that a big zip loc bag works well enough on our port filter. "Greased pig" is what happens if there's a slip-up, but mostly the big-a$$ bags are big enough so it's all manageable. And I'd probably need to use a bag anyway, even if the filter were mostly drained in advance.

I use a bag on the starboard filter, too, but that's very straightforward.

Usually the result is that the bag/filter goes into the bucket, and the bucket itself never even gets oily.

-Chris

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Luckily, I have remote fuel and oil filters so I am not having to go to the outside of my engines to change filters.

Baker,
I had a remote filter w the new engine install but was plauged w leaks so reverted to the OEM screw on (horizontal) filter. It's at least half the size of the remote so now I change the filter every oil change instead of every third change. Thinking back I remember that bit drove Marin crazy.

All,
About my horizontal ... Once it came off dry but the last time it dumped a considerable amount of oil that I was not prepared for. If I punch a hole in the top of the filter a few minutes before will the oil drain out? Speaking of Marin he did that as I recall.

"If I punch a hole in the top of the filter a few minutes before will the oil drain out?"


I have always drained the oil when hot. I punch a hole in the bottom of the filter with a center punch where I have positioned a funnel and collecting bucket below. I have two funnels and two buckets so I get both going before I begin to pump the oil out of the crankcase into a 5 gallon bucket. By the time I have both engines and genset crankcase pumped and the containers removed I am ready to pull the filters. Adding a cheap #10 metal screw to the mostly dry oil filter hole prevents a drip - I have also used duck tape there with good results. Drop the now mostly empty and not so hot filter into a large zip lock bag.