What oil should i use?

[ballena]

I will be changing the engine oil on the good ship Ballena this weekend.

CanI use a regular car multigrade from halford as long as use the right viscosity?



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[hlb]

Nearly all oils the same these days. Is it petrol or diesel. All the new oils do everything..

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Haydn

 

[ballena]

The engine is Volvo 5.0 Gi Petrol, V8

<hr width=100% size=1>V8's rule!

 

[hlb]

Just get a petrol engine oil. There all ok.

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Haydn

 

[BarryH]

The GM V8 smallblock design is about 40 years old. Oils have improved quite a bit over the years. Most people seem to run them on 15/40.

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[ballena]

Volvo Prices

Went to Volvo dealer today, Offered me fully synthetic oil fo £67 inc

I will use something like GTX or Duckhams at a sensible price from ASDA or Halfords

Thanks for the advice guys

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[sailorman]

Re: Volvo Prices

go to your "local motor factor" or little independent guy / chap
i get simi synthetic for about £11 per 5lts ( branded -Vauxhall )

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[Talbot]

Re: Volvo Prices

my recommendation would be to go to semi-synthetic, rather than the normal oil from halfords. The engine will definitely last longer.

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[hlb]

Re: Volvo Prices

I used to have synthetic oil in my engines. Mechanic was not impressed and said conventional oil is much better for older engines.

Out in the middle east years ago where oil was difficult to find in the desert. I put GTX in my 56 ton truck on the grounds that any oil is better than no oil!! It was still going 250,000 miles later.../forums/images/icons/laugh.gif

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Haydn

 

[BarryH]

Re: Volvo Prices

What a lot of people don't realise is that the cheaper "semi synthetics" are actually reclaimed oil. I don't use them cos generally thry're crap.

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[Andrew_Fanner]

Re: Volvo Prices

Halfords 15W-40 (whatever that means) £11.99/5 litres for the diesel spec. Engone manual says 15W-40 CD spec. Allegedly for non turbo diesel cars, is this going to be an issue for a turbo diesel boat? Means that the oil change will be sub £30 in oil plus the cost of the filter, which I hope a local factor can match.

Need to do an oil change some time soon and Halfords prices are attractive compared to local swindlery and indeed local motor factor unless I buy >50l. Halfords easy to drop into on way home too.

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[sailorman]

Re: Volvo Prices

diesel spec CC is generarly the lowest spec
the higher the second letter the better the oil
CC CD CF CF4 CG
done buy expensive "Brands" just read the spec. on the can

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[Cymraeg]

Re: Volvo Prices

Engine oils have generally got thinner as the tolerances in modern engines have got finer. The flip side to this is that they are generally too thin for an older engine, and may result in slight weepage or indeed consumption in the combustion chamber. As for longevity, the golden rule is that the more oil changes the longer the engine is likely to last. Castrol GTX is certainly sufficient for most applications, but I believe contains less detergents than modern semi- or fully synthetics, and therefore a mid-season oil change is likely to do more good than harm, without risking leakage which *may* occur using a thinner lubricant.

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[BarryH]

Re: Volvo Prices

Agree with that. Oils have got thinner over the years. For older engines I tend to go up a couple of grades. My old Volvo is 'sposed to be run on 15-40. Running on that is fine until you have higher revs for a prolonged period. The oil thins out even more and the oil temp rises and the pressure drops.....which it would. I now run on 20-50 which has solved the prob. Going up a couple of grades has brought down the temp at higer reves for long periods and the oil stays cooler with sustained oil pressure.
The engine never really consumed any oil and theres no "extra wear". But it does give me peace of mind.

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[Andrew_Fanner]

Re: Volvo Prices

Now that's interesting. So 20W-50 for diesels may be just the thing to stop the oil pressure whimpering on tickover after any sort of run at higher revs.

Noticed that at the start of May after a good blast from Ramsgate to London, levels fine and at >=1500 rpm nary a squeak but take it below 1000 and it, well "grizzles like a small child that's dropped its ice cream" was the simile I used last Sunday. First river trip after getting my BSS chitty and licence.

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[PaulF]

Re: Volvo Prices

Another 'consideration' for any engine run wide open for a while is NEVER to shut down from max rpm direct to a tickover. It takes a couple of minutes for the heat to dissipate into the cooling water, and if the flow rate drops like a brick the temperature can rise immediately after closing the throttle. Far better to reduce load by 50% and cut revs by 25% ( propeller load law) for a minute or two prior to dropping to tickover. This may help reduce pressure drop.

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[adarcy]

Re: Olis

<< Oils have got thinner over the years>>

Not entirely true, the oils are rated the same as far as viscosity but they have extra wear and detergent properties eg the CC to CF in earlier post. The variation in viscosity is based on newer engine design requirements not the oils changing.

15W-40 relates to a 15 grade oil when tested under the specified Winter conditions and 40 in hot "summer" conditions so it is multigrade whereas old engines (like our mower Briggs + Stratton) wants straight 30.

I used to use Mobil SHC when it came out in the car and that was a 5W-60 so I don't think it right to say oils have got thinner.

However, much more important than all this talk about viscosity and what happens to oil pressure at tickover when hot is that one should be more concerned with oil flow. If an old/used engine which has a bit of wear drops its oil pressure when hot then a lower viscosity oil will flow, if you put a thicker one in to get a higher pressure reading that does not necessarily mean you are getting a faster flow through the bearings, the pump may reduce its flow rate providing the higher pressure.

IMHO one ought to use the same viscosity spec oil the engine was designed for but up the spec Eg CD CF and disregard the pressure unless you can actually hear a bearing rattle ( in which case fix it or put sawdust in it and sell it) rather than use thicker oil

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[chippie]

Re: Olis

Re winter and summer conditions; 15w40 I was under the impression that the lower number indicated the viscosity at startup and the higher one indicated it at running temp. Am I wrong?

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[TrueBlue]

Oil grades

Beware if changing the specification (CD etc), higher spec: oils are more 'slippery' and tend to 'glaze the bores' if the engine is lightly loaded. This results in loads of blue smoke when running on rivers. Stick to CD and change the oil more often if you're bothered.

Modern synthetic oils (5W, 0W etc) are designed for long service interval, high performance petrol engines; fine if you don't mind throwing money at your boat, but in any even I would stick to two oil changes a year (or more) in an oli burner, certainly if the unit has pretententions of being 'marine' (not 'marinised').

For what it's worth.

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ICOS X: Stop what you're doing and wait my signal

 

[adarcy]

Re: Nearly

I "think" I specified the W as "specified winter conditions" but skipped over the "summer" situation for brevity - sorry.

There are various set conditions (mainly temperature but I think ambient pressure and humidity) under which oils are tested to compare their viscosity. So under W conditions a 15W-40 oil will have the characteristics of a "straight" 15 oil but under non-mentioned ( ie hot/summer/ "normal" running) it behaves as a "straight" 40 oil would. In effect you are mostly right at startup ie stone cold you are interested in the W rating and while you're thrashing it the 40 rating. However, a landlocked car in the Arctic doing short-medium runs may never get to our idea of running temperature in its oil and a car in the tropics never gets stone cold in our sense.

therefore the oils are tested under specific conditions but your shorthand is all that matters in temperate zones

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