Worth doing an oil change?

I mentioned earlier that I have no gauges ..

Horrors of horrors - but I don't have Rev Counter, don't have Temp gauge, don't have Oil pressure gauge. Terrible ... I think about it sometimes but then think - its been like that since mid 70's ....
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actually I have two.

One is dual battery gauge ... so I can see what each battery state is. Second is a Fuel Gauge that shows FULL all the time .... yes - I'm trying to fix that one ...

But I don't think really I need a temp gauge when I have a cooling system that pumps as if its part of local Fire Brigade ! I know I should close in the inlet seacock to reduce it (raw cooled) but at least I know I am not running risk of salt deposits from running too warm ... Perkins make specific mention for Raw system to run cooler than Heat Exchange systems.
 
I change the oil on my Perkins when the book says, my engine is running around 8 hours a day. I think I get all the old stuff out, but after a day it is black again, why is this?
Sorry to hijack
 
Because it is doing its job, the detergent cleans up the carbon sludge inside.

Do you drain with the sump plug and is it actually the bottom of the sump or are you sucking on the dipstick tube?
Filter changed at the same time?

There is nothing wrong with black oil. It works just as well as green, brown or red.
 
northcave said:
I changed the 10L of oil in my 25 year old Perkins 80HP at the end of summer last year before layup. We’ve since done a summer of cruising permanently since April but not a huge amount of motoring to be honest. Spent most of the time in the Scillies and tootling between anchorages. Not sure of the hours as my counter doesn’t work.

The oil is still clear and I’m about to lay up for 18 months.

Change or not worth it if it’s still clear?
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If clear and not dirty, I'd not change it. Remarkable to have clear oil in a diesel engine for very long so sounds like it is good to me.
 
38mess said:
I change the oil on my Perkins when the book says, my engine is running around 8 hours a day. I think I get all the old stuff out, but after a day it is black again, why is this?
Sorry to hijack
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Isn't there some expensive people that perform engine flushes to get all dirt out or am I thinking of something else? And is it worth the expense of a flush?
 
Boater Sam said:
Because it is doing its job, the detergent cleans up the carbon sludge inside.

Do you drain with the sump plug and is it actually the bottom of the sump or are you sucking on the dipstick tube?
Filter changed at the same time?

There is nothing wrong with black oil. It works just as well as green, brown or red.
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Do you have a magnet on your drain plug?
 
RichardS said:
The only realistic solution if your engine does have a build-up of sludge is to remove the sump and physically clean it out. I've done it with many car and bikes engines over the last 55 years although I appreciate that it is usually much harder with boat engines. Any other method used to remove sludge is as likely to do as much damage to the engine as it resolves. :(
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That's the main reason I do not like sucking used oil out of the dipstick hole: most of the sludge inevitably stays behind and accumulates.
 
Moodysailor said:
Studies done by several marine engine manufacturers showed that condensation can build up on the inside of the engine block (I was involved with one at Perkins Sabre, and I know Volvo Penta and Yanmar have done similar testing). This is due to the nature of the environment - damp & humid atmosphere and a large temperature range.
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In a laid-up engine?
 
Boater Sam said:
Because it is doing its job, the detergent cleans up the carbon sludge inside.

Do you drain with the sump plug and is it actually the bottom of the sump or are you sucking on the dipstick tube?
Filter changed at the same time?

There is nothing wrong with black oil. It works just as well as green, brown or red.
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I drain from the sump plug, I don't like the sucking up the dipstick tube idea. It's a good thing my engine is easy to service. New filter every time
 
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JumbleDuck said:
In a laid-up engine?
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Yes, and No.

Some condensation will always be generated simply due to the fact that there is air in the crankcase.

If the engine is properly laid-up - as in inhibited - with the correct inhibiting fluids used, raw water system drained & flushed, fuel system treated and orifices blocked then this is greatly reduced. This is not normally needed unless laying up for extended periods (longer than 12 months). If laying up for shorter periods (up to 6 months) then fresh oil, drain & flush raw water system, stuff rag up exhaust & cap off air intake is all that is needed to help.

The greatest risk to a laid-up engine is not from contamination in the oil/sump, it is actually upper-cylinder corrosion from damp air getting into a part of the engine which has no corrosion protection as standard, and damage to the fuel system. When I worked at Perkins Sabre, we had to provide engine to military which were inhibited for long-term storage. The process for that is actually quite onerous and detailed. The good news is that 80% of the work can be done easily, as mentioned above.
 
JumbleDuck said:
That's the main reason I do not like sucking used oil out of the dipstick hole: most of the sludge inevitably stays behind and accumulates.
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If the engine is fairly clean (i.e no heavy build up of deposits) and is run until warm before draining the oil then most particles will remain in suspension in the oil and will be sucked out. As mentioned in some earlier posts, modern oils are actually very clever, and contain (amongst other things) detergents and additives that break down deposits and hold them in suspension.

The main purpose of these is to keep the engines clean for maximum efficiency, and to transfer deposits to the oil filter where they can be trapped, but they also act to help during servicing.

It's one reason I will never suck out oil if it has been left standing as the deposits will settle out. It's also another good reason to buy good quality oil (not necessarily branded, just good quality) and to change oil regularly.

But it is OK to use the vacuum extraction method. Quite a number of manufacturers of marine engines provide oil extraction tubes or pumps on the engines.
 
CFG98 said:
If clear and not dirty, I'd not change it. Remarkable to have clear oil in a diesel engine for very long so sounds like it is good to me.
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A little background my help. So when I bought the boat in 2014 it was in the Rustler yard and they were asked to recommission the boat and put new oil in prior to the sea trial. I checked the oil prior to the trial and it was full but fairly black. I purchased the boat and a day later sailed it back to Bristol. However, on arriving in Newlyn I realised there was no oil on the dip stick. It had mostly come out into the bilge. I refilled it and bought another 10L to get me back. A little motoring later and it had emptied out again into the bilge. Another 10L went in.

When I eventually got back to Bristol I relised the oil filter had been cross threaded onto the engine so it was an easy fix. However the result was that the engine got about 20L of new oil flushed through it. Ever since, and that was 6 years ago, it has been clear even after a year of heavy use.

Note: the oil was not pumped out. It was collected in Bristol and disposed of. Horrible job.
 
RichardS said:
Good grief ..... first time I've heard of that although it proves that if it's possible to cock up a simple job, someone will manage to do it. :(

Richard
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Hard to believe, it must have taken considerable mental shortcomings to manage to cross thread a spin on canister and not check, as advised, for leaks with the engine running.
We did have a spate of Ford Transit oil filters bursting but it turned out to be defective pressure release valves.
 
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