Oil change interval

[Newtrawlerowner]

I wanted to know what the oil change interval should be on a diesel engine. I have a Caterpillar 3126 and did change the oil and do a major service when I first purchased it. I've been doing some dockside upgrades and am ready to do a Loop trip. I have maybe 30 hours since the last change and wanted to know when I should do the next oil change. I previously owned a sailboat with a Yanmar and would change every 100 hours.

 

[mvweebles]

100 hours is, by far, the most common number I've seen. I've started to put quite a few hours on my engine so have around 200 hours over last few months and will change soon along with impellor change. Timing is good as I'm in a marina in Mazatlan. I probably won't change again for another 200 hours or so when we make Costa Rica in the spring. I think some of the change interval calculus is driven by how much you use your boat. While I also think it's a bit of a wives take that oil sitting in an engine causes acids, I also think that changing annually regardless of hours is a good idea.

Perkins 4.236 75hp.

Peter

 

[Larry M]

I think the “book” says 250 hours for the 3126 but that seems long.

We use to change ours at 150-200 hours based on location and how convenient.

 

[O C Diver]

I've shifted around from 100 to 200 hours, currently at 125. My approach would be to setup a Blackstone Lab oil analysis account. Then maybe adjust the interval in 25 hour increments with oil analysis, until you see the wear metals increase. Then back off 25 hours, do a few changes at that interval, and see if your happy with the analysis.

Lot to be said for repeatable numbers. 125, 250, 375, 500, 625, 750, 875, 1,000.........repeat.

Ted

 

[Jeff F]

I think the “book” says 250 hours for the 3126 but that seems long.

It seems long for older engines. But the 3126 was developed 25+ years after the Perkins and Ford engines. My observation is that manufacturers recommendations have changed over the years to recognize the improvements in manufacturing tolerances and oil technology.

My view is that for typical trawler use there is no reason to change more often than the book recommended interval. If you're concerned beyond that a testing regime like Ted suggests will provide assurance, and may lead to extending intervals beyond the manufacturers guidance.

 

[Jeff F]

I've shifted around from 100 to 200 hours, currently at 125.

I'm interested in your findings. I'm following the book recommendation of 375 hours for the same engine with a similar use pattern. No testing, but the oil coming out looks like it could have run 20 hours in older engines I've owned.

 

[Insequent]

For my Tier II John Deere's I change oil & filter at 250 hour intervals, which effectively is once per year. I get an oil analysis at every change. Could I go longer? Probably, but the book says 250 hours. The book also says evey six months, but given the analyses are always perfect I'm happy to go longer time-wise.

 

[fgarriso]

I would change it every 100 hours with a new CAT oil filter. That black stuff is carbon and junk you don't want in your oil and or engine. Oil is the cheapest thing you can do to extend your engine life.
If you're going to do the loop, you can do it every two weeks running 7 hours a day and be on schedule.

 

[DennisB1]

Cat recommends 250 hrs. Better is to have the oil tested and follow the analysis recomendations. I use a synthetic oil and have several seasons along with the analysis to determine when to change oil. The annual analysis also gives you info on engine potential problems.

 

[Jeff F]

...Could I go longer? Probably, but the book says 250 hours. The book also says evey six months, but given the analyses are always perfect I'm happy to go longer time-wise.

Are you sure the book says 250 hrs? My book says 250 hours everywhere, but then specifies in the details that this can be extended to 375 when using a JD filter and any approved oil.

Just FYI.

 

[O C Diver]

I'm interested in your findings. I'm following the book recommendation of 375 hours for the same engine with a similar use pattern. No testing, but the oil coming out looks like it could have run 20 hours in older engines I've owned.

My tier 2 Deere didn't like JD oil. Started getting some lead (bearings) in the analysis. Iron and aluminum were higher than I wanted. Cut back to 100 hours till I passed the 2 year warranty period.

Switched to Rotella T4 (15W/40 dinosaur oil) which I've used in the charter boat (Cummins 6CT) and my Dodge pickup (Cummins 6BT) for the last 20 years. Lead is now below 1+/- PPM, aluminum hovers around 2 PPM, iron is around 7 PPM. Went to 125 hours and then 150. At 175 hours I was approaching universal averages for Blackstone.

Every 125 hours is easier to remember as it repeats every 1,000. Think I did 8 changes this year. An oil change is $50, $75 with oil analysis. In the relative cost of cruising, it's below 1% for me, and a rounding error on the budget.

Ted

 

[Insequent]

Ted, with those prices I would do the same!

I bought oil test kits a few months ago. With postage to lab included they came to A$69 each. Then there is the oil. I stocked up 2.5 years ago when it was on special at one of my regular suppliers, and it was A$95 (20 litres). I have just used the last of that, and will wait for a special again - I was in the shop a few days ago and regular price is A$205 (20 litres). Inflation is in single digits they say - yeah, right!

I used the JD break -in oil for the first 100 hours and that was it. For the last 10 years I've been using Castrol RX Super, 15W40. Not planning to change to anything else.

 

[O C Diver]

Ted, with those prices I would do the same!

I bought oil test kits a few months ago. With postage to lab included they came to A$69 each. Then there is the oil. I stocked up 2.5 years ago when it was on special at one of my regular suppliers, and it was A$95 (20 litres). I have just used the last of that, and will wait for a special again - I was in the shop a few days ago and regular price is A$205 (20 litres). Inflation is in single digits they say - yeah, right!

I used the JD break -in oil for the first 100 hours and that was it. For the last 10 years I've been using Castrol RX Super, 15W40. Not planning to change to anything else.

20 liters of oil this year cost me about $85 US.

But then you can probably offset your oil prices with the inexpensive fuel. Over the road fuel is around $3.60 per gallon in SW Fl. All kidding aside, if I had to pay what you pay for fuel, I'd slow down so much I'd probably be going backwards.

Ted

 

[SteveK]

100 hours is, by far, the most common number I've seen. I've started to put quite a few hours on my engine so have around 200 hours over last few months and will change soon along with impellor change. Timing is good as I'm in a marina in Mazatlan. I probably won't change again for another 200 hours or so when we make Costa Rica in the spring. I think some of the change interval calculus is driven by how much you use your boat. While I also think it's a bit of a wives take that oil sitting in an engine causes acids, I also think that changing annually regardless of hours is a good idea.

Perkins 4.236 75hp.

Peter

Get a sample tested and share results. With mostly continuous hours it will be interesting to see those results. No way I will change every 100 hours since testing shows the oil can keep going. This of course is without intrusion of coolant or sea water or other intrusion into normal operations.

 

[kchace]

The manual for my Perkins engines (6.354 naturals) states 200hrs. Coming down from Newfoundland I actually exceeded that by about 20 hours. Testing by Blackstone confirmed that the Rotella 15-40 was still ok with only slightly elevated wear metals. So for my engines, it seems 200 as stated in the manual is ok, but probably not more.

Ken

 

[SteveK]

The manual for my Perkins engines (6.354 naturals) states 200hrs. Coming down from Newfoundland I actually exceeded that by about 20 hours. Testing by Blackstone confirmed that the Rotella 15-40 was still ok with only slightly elevated wear metals. So for my engines, it seems 200 as stated in the manual is ok, but probably not more.

Ken

sorry but if Blackstone said OK then you can keep going until it is not, cant you? Oil lasts longer than decades ago.

 

[kchace]

sorry but if Blackstone said OK then you can keep going until it is not, cant you? Oil lasts longer than decades ago.

Sure, but I need something I can plan on. I don’t want to keep testing until it’s time.

Ken

 

[klee wyck]

Are you sure the book says 250 hrs? My book says 250 hours everywhere, but then specifies in the details that this can be extended to 375 when using a JD filter and any approved oil.

Just FYI.

That is what I see for my 6081 AFM JD engines. I use the JD Plus oil so use 375 as upper limit. Because the calendar usually hits me first in terms of suggested intervals, I have never gotten to 375. Even with JD oil and 50% extension of time interval, they suggest no more than 9 months.

I really do not understand the time component of service intervals.....hours of use makes way more sense to me than calendar days.

 

[Irish Rambler]

mvweebles mentioned that he thought tales of acid in oil were not true.
Please may I explain.
When an engine is started and is driven to operating temperature its passes through a phase called the 'dew point'.
This 'dew point' is when acid is produced and is absorbed in the oil.
If you find an engine which is overdue its oil change, take a dab of fresh oil and put it on your tongue and taste it, now take a dab of old oil and taste it and you will feel the acidity.
Irrespective of hours I always change the oil at the end of the season so the engine is in clean fresh oil while it layed up over winter.
Oil is cheaper than metal.
I have never fitted bearings on any engine and our truck engines have over 650,000 miles and boat engines have never been lifted out.

 

[DennisB1]

The selected oil should have a high “total base number” or TBN to neutralize acids. Also this should be checked in the oil analysis as part of the determination to continue using or changing the oil.

 

[Don L]

I wonder what the difference would be between analysis of oil from the sump and oil after the oil filter. I bet even if you are in the extend oil hours between changes camp it is still worth changing the filter.

 

[rslifkin]

I wonder what the difference would be between analysis of oil from the sump and oil after the oil filter. I bet even if you are in the extend oil hours between changes camp it is still worth changing the filter.

It depends on how big the filter is on a given engine vs the particle loading the oil experiences. If you're loading up the filter enough to be going into filter bypass at times later in the oil change cycle, then yes, changing the filter would be a benefit. But if the filter isn't getting loaded up too much during the cycle, then changing it wouldn't help anything.

 

[Don L]

It depends on how big the filter is on a given engine vs the particle loading the oil experiences. If you're loading up the filter enough to be going into filter bypass at times later in the oil change cycle, then yes, changing the filter would be a benefit. But if the filter isn't getting loaded up too much during the cycle, then changing it wouldn't help anything.

And how would you know this?

I would think this really means you are way past time to change the oil if it is clogging up filters. I acturally think this probably means your engine is on its last hours if it has that much wear materials in the oil.

 

[rslifkin]

And how would you know this?

I would think this really means you are way past time to change the oil if it is clogging up filters. I acturally think this probably means your engine is on its last hours if it has that much wear materials in the oil.

Unless the engine has a particularly small filter, that's likely correct and means that an early filter change isn't worth worrying about. Although things like diesel soot in the oil will contribute to filter loading. You can cut a filter open after a change to get an idea of what's in it. But I don't know of an easy way to measure whether the filter bypass valve is opening or not.

 

[RickyD]

I think the “book” says 250 hours for the 3126 but that seems long.

We use to change ours at 150-200 hours based on location and how convenient.

I agree. I believe it is engine hours and time dependent. If you are like Peter and running regularly I'd extend the change period to the 250 hour book. For me and my 3208s, it takes me a long time to get to 100 hours so I use that as a standard.

 

[plittle2005]

Unless the engine has a particularly small filter, that's likely correct and means that an early filter change isn't worth worrying about. Although things like diesel soot in the oil will contribute to filter loading. You can cut a filter open after a change to get an idea of what's in it. But I don't know of an easy way to measure whether the filter bypass valve is opening or not.

rslfkin, what filters do you use on your 454's? I have been using Fram PH8's for convenience, but every change (at winter layup, avg 400m@8mph=50hrs) the drain oil is black, appears sludgy.


I use Rotella T4 15w40 for the Zn and have about 1200 hrs on them. Never had an analysis. Is there a more effective filter? Thanks.

 

[rslifkin]

rslfkin, what filters do you use on your 454's? I have been using Fram PH8's for convenience, but every change (at winter layup, avg 400m@8mph=50hrs) the drain oil is black, appears sludgy.


I use Rotella T4 15w40 for the Zn and have about 1200 hrs on them. Never had an analysis. Is there a more effective filter? Thanks.

I've never had oil come out of mine looking particularly bad and I usually have more hours on the oil than you do by change time. For filters, I usually use the Wix 51086, as they're a better built filter than the cheap Frams and have an anti drainback valve.

Mine ran on 15W-40 T4 for a while, lately they've been getting Delo 15W-40 semi-syn or the Rotella T5 15W-40 semi-syn. The change in oil didn't produce any noticeable change.

If you're running at low speeds all the time, what temperature thermostats do you have in the engines? And are they closed cooling? Do you periodically run on plane for a few minutes to get things good and hot?

 

[JackConnick]

On my Cummins 6BT 5.9s the manual says every 250 hours or _3 months_.
Its a new boat to me, but after 100 hours I had the oil (Delo 15-40) analyzed and it came back fine. I'll probably change it later this spring short of 200 hours before we leave on a longer trip.
But I'm wondering about the time interval on oil changes, particularly Cummins saying 3 months - which seem insanely short.


Jack

 

[plittle2005]

I've never had oil come out of mine looking particularly bad and I usually have more hours on the oil than you do by change time. For filters, I usually use the Wix 51086, as they're a better built filter than the cheap Frams and have an anti drainback valve.

Mine ran on 15W-40 T4 for a while, lately they've been getting Delo 15W-40 semi-syn or the Rotella T5 15W-40 semi-syn. The change in oil didn't produce any noticeable change.

If you're running at low speeds all the time, what temperature thermostats do you have in the engines? And are they closed cooling? Do you periodically run on plane for a few minutes to get things good and hot?

Thanks. I will switch to Wix and goose it periodically. I have Crusader FWC's and run 175 F (on the gages), 8-9 hours daily, continuously, and about 38 psi oil, very steady. On my first cruise, 600 miles, last year, they ran in the 140's. I found the PO had removed the t'stats! Replaced with nominal 160's, which now run in the 170's.

FWIW, I use a Walmart pump https://www.walmart.com/ip/Hyper-To...-36200WDI/861807696?athbdg=L1103&from=/search ($11.00) whose hose fits snugly on the dipstick tube OD, and a 5-gal bucket to change oil. Takes 30 minutes to drain and refill both engines. A $100+ oil change system is sorta overkill!

 

[rslifkin]

Thanks. I will switch to Wix and goose it periodically. I have Crusader FWC's and run 175 F (on the gages), 8-9 hours daily, continuously, and about 38 psi oil, very steady. On my first cruise, 600 miles, last year, they ran in the 140's. I found the PO had removed the t'stats! Replaced with nominal 160's, which now run in the 170's.

FWIW, I use a Walmart pump https://www.walmart.com/ip/Hyper-To...-36200WDI/861807696?athbdg=L1103&from=/search ($11.00) whose hose fits snugly on the dipstick tube OD, and a 5-gal bucket to change oil. Takes 30 minutes to drain and refill both engines. A $100+ oil change system is sorta overkill!

Those temperatures are fine, although there are likely no oil cooler thermostats. If you're running at low speed all the time the oil is likely running pretty cold and not cooking off moisture all that well. Consider adding thermostats to bypass the oil coolers until the oil gets hot enough. Running 5 - 10 minutes on plane periodically will also get the oil temps up and help the situation.



Check that the filter part number is the same for your engines. Mine are Mercs, so it's possible they used a different filter mount thread, etc.