Engine oil flushing

[Liam]

We try and change the engine oil once every 6 months if we can get round to it... and the time has come for the next one which will hopefully get done this weekend.

 

We have the filter and the oil but I am wondering whether there is any plus points about using flushing oil to try and flush it all out before putting the new stuff back in. I did a quick Google to see what people had to say about it and although lots of people said they wouldn't bother or have been told not to use it they don't give any reasons.

 

What do you think?

[alan_fincher]

I wouldn't even think of it unless you are draining through a sump plug, and are confident that just about all oil in the engine will drain through it.

 

If you have an arrangement like us of a brass pump to "suck" the oil oil, then it's very obvious that an awful lot gets left in, (our total oil capacity should very nearly use a whole 5 litre can, but on our last change I must have had at least half a litre remaining).

 

That means there was half a litre of old oil at the bottom that the pump doesn't get.

 

So if I put flushing oil in, I'd be left with around half a litre of that mixed with my new oil. That doesn't sound good to me.....

 

Alan

[Liam]

Hi Alan,

 

I was thinking about using the flushing oil because, like you, we have the brass pump arrangement and, also like what you found, some must be left in and as the lumpy stuff gets left at the bottom, it would sound like a good idea, but, now you mention the flushing stuff being left in it wouldn't make sense.

 

Ideally, like on my old Sabb, where you can remove the crank case door, and get in with an old rag to clean it out but the D3 lacks this (as far as I know, as I can't see them).

 

Just a simple oil change it is then... thanks for the info.

[NB Esk]

Hi Liam, one of the objections to flushing oil, is that in extreme cases it can lead to real problems.

 

If an engine has produced an excessive amount of sludge, the use of flushing oil can dislodge deposits, which in turn can partially block the oil pump pick-up pipe, in the sump.

 

I don't need to spell out what happens next.......so the use of flushing oil warrants consideration.

Personally, any doubt, I wouldn't bother with it...

[Liam]

Hi John,

 

The main reason why I thought of this was because I haven't seen inside the engine and thought, innocently, it would be best to try and clear it. Now, thinking about it, along with yours and Alens kind advice I have sensibly decided to opt against using flushing oil and look forward to a straight oil and filter change this weekend.

 

Now, next question... I did check the engine over last weekend to see whether the Perkins D3 did have crank case doors but couldn't see them. Does this engine have them?

 

Thanks again

[NB Esk]

Hi Liam, Don't know.....not familier with your engine.

 

"Crankcase doors" usually take the form of one large or a number of smaller cast iron plates, bolted on to the side of the crankcase. They may well be disguised with other components fastened to them, oil filler, dipstick, filter unit etc.

 

However, they will invariably be on the same line as the crankshaft.

 

Look at the big end caps on the con rods, on my avatar. They are the sort you can expect to find behind crankcase doors (angled to one side)...

[Proper Job]

I'm virtually sure that the Perkins D3 does not have crank case doors. Most of the ancillaries are bolted direct to the side of the block (fuel, oil filter etc).

 

As you can see from the picci below, Crankcase doors are fairly obvious if fitted:

 

 

My National has a seperate sump bolted below the bottom of the crankcase and a nice door to open, that a small child/SWMBO can get a hand in to remove all of the sludge. It's also why a non modern grade engine oil without detergents must be used (for my engine). Modern oils keep the muck in suspension rather than let it fall to the bottom of the sump to be wiped out as part of an oil change.

[Liam]

What a beast! A lovely looking engine... bet it gives off a wonderful exhaust note...

 

Crank case doors, like mentioned above, are very obvious but I couldn't see any so that must mean one thing... it doesn't have any!

 

When the piston shattered and the push rod broke in half, in my 10hp single Sabb, I took it out of the boat to sort it and took advantage of this and cleaned the whole engine from the outside in, when the crank case door was off.

[Proper Job]

What a beast! A lovely looking engine... bet it gives off a wonderful exhaust note...

 

Crank case doors, like mentioned above, are very obvious but I couldn't see any so that must mean one thing... it doesn't have any!

 

When the piston shattered and the push rod broke in half, in my 10hp single Sabb, I took it out of the boat to sort it and took advantage of this and cleaned the whole engine from the outside in, when the crank case door was off.

At the moment it doesn't give any exhaust note, but having heard Warrior Womans 3 lung National at the weekend, I know it will when its finished.

 

You can check progress by clicking on the link at the bottom of my signature - National 3D