How Often Do You Change Your Oil ?

[Troubadour52993]

I have heard every 100 hours or annually, but on the diesel for my generator that's about every 6 weeks or so. Is this the equivalent to every 3000 miles on a car, and it's best to do it religiously, or do people just change it every 3 months or so if running daily?

[SoonerSailor]

100 hours is probably roughly equivalent to 3000 miles in a car. I've never had a diesel car, so don't know what oil change intervals they recommend.

Diesel engines put a lot of soot into the oil, which a normal oil filter does not remove. That means that even though the base oil and additives would still be fine without the soot load, you still need to change it out because the soot is a source of wear. Some industrial diesel engines, and some truck engines will use a very fine bypass (as opposed to a full flow) oil filter to remove this soot and achieve very long drain intervals.

Hopefully your oil is easy to change. Its pretty cheap compared to wear on the engine. If you really want to lengthen your drain intervals (and perhaps extend the life or your engine), consider an aftermarket bypass filtration system. You might find that changing the bypass filter is as much of a hassle and expense as just changing the oil frequently.

[capt_douglas]

I don't know what make of generator you have or its capacity but the quart or two it takes to do the change should be cheap to the potential problems worn out oil can produce. You might consider synthetic oil as it seems to have a much longer run until change life (2-3x isn't uncommon) but at a higher cost. If changing the oil is a pain, this might be the way to go.

I change oil on my genset according to the mfgr guidelines. It sounds like the genset runs fairly regularly (~15hr/wk) but if it's used only on the weekends (100 hrs in 6 weeks) then it may spend more time sitting than running and that operation style can reduce reliability. Every mechanic I've talked to say changing the oil is the cheapest way to keep the engine healthy.

[Therapy]

I don't have a generator but my diesel gets it more often than the 100 hrs recommended.

Cheap insurnace.

[S/V Illusion]

We've all seen recommended intervals between oil changes but it is only a general guide. It really depends upon how and how often you use the engine - short-term low rpm use creates more soot; longer high temperature runs are more forgiving. It also depends on how old the engine is, integrity of the piston rings, proper timing, etc...

There is no such thing as one correct answer so simply follow the engine mfgs recommended intervals as a minimum depending on the above.

[Troubadour52993]

Thanks for the responses. Changing the oil is not a terrible procedure, so I was just wondering if this was the right interval. So far I've been keeping the 100 hour schedule; once when I started using it and once at 100 hours.

The manual for the Perkins 4-236 main engine says every 200 hours, but I don't have the manual for the Perkins 103-7/Perama M20 on the generator so I'm not sure what the manufacturer recommended interval was.

I was told to change at 100 hours, but have also had that scoffed at by people who say that some power boats run the generators 24 hours a day to run air-conditioning, etc. and they probably only change the oil every few months so thousands of hours between oil changes. Just curious to see what others do, since I couldn't find any other threads.

[JiffyLube]

I change the oil and filter on our sailboat's diesel engine every 100 hours, or three months...what ever comes first.

[klem]

The only way that you will know for sure is to get an oil analysis. There are several places including Blackstone Labs where you can send an oil sample to and how long you have run it and they will give you a full report on the condition of your oil and how much life it has left in it. So next time when you change it, pay the couple of bucks to get an oil analysis and know for sure.

If you don't like the results from your analysis, you can attempt to extend the intervals using synthetic oil and a bypass filtration system.

[KittiwakeCD28]

change the oil every 100-120 hr in Volvo MD7A, as per Volvo manual...

[hummingway]

Originally Posted by JiffyLube

I change the oil and filter on our sailboat's diesel engine every 100 hours, or three months...what ever comes first.

This is the recomendation for my engine as well. Perkins points out that the three months is because condensation can occur whe the engine isn't being run.

[svcattales]

I just switched to synthetic oil on my last oil change. AMSOIL claims you can go 200 hours on a diesel between changes. I started a thread about this a few months ago with my rationale for switching.

On our last cruise we put 150 hrs on starboard engine and 170 hrs on port engine. The starboard oil is black, but not near as sooty as petroleum oil after 20 hrs. The port oil (170 hrs) is not black and looks like it is in good shape. I did change both filters at 100 hrs to remove any junk from oil.

I just sent oil samples from both engines off for testing, so I should know whether the oil is still in good shape. Stay tuned for results.

[svcattales]

See thread on Synthetic Oil Change Frequency for more info.

[JiffyLube]

Originally Posted by hummingway

This is the recomendation for my engine as well. Perkins points out that the three months is because condensation can occur whe the engine isn't being run.

It takes a long time to get 100 hours on most sailboat diesels, so changing the oil every three months is a good idea. Mainly it's a good idea to change more often, because the longer the contaminated oil sits in the engine the worse it is for the engine. An engine with new oil only has to be run once to contaminate the oil with diesel fuel, then the contaminated oil/fuel mix creates an acid that eats at the insides of the engine. Granted the acid is not that corrosive at three months, but the longer the engine is used or sits the more corrosive the mix gets.

[Charlie]

I have a Yanmar 4JH4E the recommended change time is 250 hours. I usually change somewhere between 100 and 200 or if the oil looks really black.

[Bash]

I change the oil once a year.

Religiously.