Semi synthetic diesel engine oil

[msimms]

Anybody see a problem using semi synthetic oil in an AD31?


OPTIMA VIMAX DIESEL 10W/40 (SEMI SYNTHETIC)
Semi synthetic fuel efficient multi grade engine oil for use in latest technology turbo charged and naturally aspirated diesel and petrol engines requiring the latest A.C.E.A. and A.P.I. specifications. Also recommended for use in LPG powered systems A.C.E.A. A3, B3, B4. A.P.I. CH4/SL. MB 229.1

Cheers

Mark

 

[Wiggo]

maybe. I don't know how this works, but I'm told you should not mix oil types. I think it may be more of an issue if you top up with a different type, though. I think teh standard Volvo stuff is semi synthetic, however. Col knows more about this, I think...

 

[Talbot]

No problem mixing semi syn with normal as after all that is what was in the mix to start with. But may be a problem mixining fully syn with non-syn oil.

 

[Wiggo]

Indeed. Just found this...

When switching to a synthetic motor oil, it is important to keep several things in mind regarding oil consumption. Keep extra quarts of synthetic handy. Although many synthetic oil manufacturers tout the compatibility of their oils with mineral-based oils, adding mineral oil to synthetic oil will drastically reduce the level of engine protection that was initially designed into the synthetic oil as well as the mileage to your next oil change. Also, as the mineral oil breaks down it will contaminate the rest of the oil, leaving sludge and varnish deposits in the engine (this is because mineral oil is made up of many chemically dissimilar hydrocarbons, including waxes, all of which react differently under different operating conditions). By adding a mineral oil to synthetic oil you will also see a reduction in engine efficiency. depending on how much, and when, the mineral-based oil was introduced.

And this:

There can be several circumstances associated with an increase in oil consumption and a variety of reasons for them. Probably the most common reason is a failure of valve stem seals which permits oil to be drawn down the clearance between the valve stem and the valve guide. There is usually an increase in consumption after changing oil brands. In this scenario, it is usually only for a short period of time and then returns to its previous low level. The change occurs because motor oils differ in additive packages, which make up about 20% of the product. This change in the detergent/dispersant chemistry tends to remove previously deposited material that is helping to seal. Once this deposit is removed, the new chemistry will produce a deposit that regains full sealing benefits and controls oil consumption to the original lower level. Any increased oil consumption not related to these circumstances is generally due to a mechanical problem.

 

[Wiggo]

Well, a bunch of digging would lead me to conclude that as long as it is a diesel oil, and has the right viscosity, it should be OK. However, it seems that you would be well advised to drain the engine, run flushing oil through, then refill with your chosen oil and then stick to it. You may see higher oil consumption for a while, but this should settle down, as long as you do not keep topping up with whatever comes to hand.

I have been guilty of this last sin, and my oil consumption has been quite high, so guess what my New Year Resolution is going to be...

 

[BarryH]

[ QUOTE ]
I have been guilty of this last sin, and my oil consumption has been quite high, so guess what my New Year Resolution is going to be...

[/ QUOTE ]




..........drink more? Things always look better after a drink??

FWIW I'd stick with the mineral stuff if the engine has been fed on that for most of its life. Unless the oil has been kept clean. ie, regular changes etc, then the synthetic stuff will as you say, break down deposits. I've seen these deposits do damage to main and big end bearings in the past. Useing the flushing oil doesn't do much to clear the years of build up. Filters don't always stop it!
I doubt you'll see much of an improvement anyhoo. The engine is quite an old design and tolerances now that its run a few hundred hours ain't what they used to be.....if you know what I mean?
I'd be inclined to run the mineral stuff and get into the habit of good oil housekeeping. I change mine 3 times a year if the boats in commision for the whole year or twice if I have a period of layup.
On that point never let and engine sit idle for the winter without changing the oil. Specially with diesels. Theres quite a build up of acids in the oil from the combustion process. These with kill the white metal of the bearings

All IMHO of course and if it all goes tits up don't blame me!

 

[BarryH]

Just re read the post. SEMI SYNTHETIC.....treat it as mineral. The semi bit is a grey area. Detrgents and all that. Read the label carefully. I got hold of some semi at a good price. On the label in small print it said "contains 30% reclaimed oil" Bloody cheek second hand stuff mixed with fairy liquid!!