BMW 3 series E30

Since 1983-1994 of release

Repair and car operation

14.7. A rule 35

THE GENERAL DATA

Engine oil can be changed by the winter. And whether it is necessary? Certainly, yes, if now in картере your car oil summer laps: морозец will strike and to lap it will cease, will freeze. There will be problems. But if you use all-weather oil to change it only because winter is at hand, not so necessarily. The main thing not to go by one oil refuelling of longer put. It is told in the service book of the car to change oil through N thousand in km of run – change through N.

Cheap but good or expensively yes it is lovely?

Immemorial question: mineral water or synthetics? Synthetic – фторуглеродные, диэфирные, silicone, полиалкиленгликолевые – on the properties it is, of course, better some oil mineral (oil). First, at synthetic much more low hardening temperature. Secondly, with change of temperature at them viscosity less varies, and that is very important, they are not diluted at very strong heating. Thirdly, they evaporate less and burn out. Fourthly, form less adjournment polluting the engine: deposits, varnishes and шламов (ointments). Fifthly, their resource of times in five above, than mineral. Sixthly, at synthetics use less mechanical losses in the engine and deterioration of details. The list of advantages can be continued still points on ten. One only a lack – the price. Synthetic is more expensive mineral in three-five times. Serious blow on a purse. If synthetics is heavy for a pocket, and mineral water you essentially do not recognise, buy semisynthetics is quite reasonable compromise.

In a consolation house-keepers should notice that mineral oils in itself are not so bad. If synthetics it is expensive yes lovely, mineral water – cheap but good. A century went by mineral water and, probably, even a century will go. By the way, in the old car guzzling oil to fill in synthetics it is not meaningful: oil and money take off for an exhaust pipe; on доливке it is possible to be ruined. Remember that to mix mineral oils with synthetic it is impossible. To change mineral water for synthetics (and on the contrary) it is possible without problems, it is necessary only between them minutes twenty to send on errands the engine on special промывочном oil.

Subtract from 35

Oils classify on two nominations: on viscosity and on quality. Viscosity. The international scale SAE provides 11 classes of viscosity. Six winter: 0W, 5W, 10W, 15W, 20W and 25W (W – winter, winter). And five summer: 20, 30, 40, 50 and 60. All-weather grades designate double marks, for example, 15W-40 or 10W-30, etc.

Not to make the wrong choice oils by the winter, it is useful to remember a so-called rule 35. It is necessary to subtract a winter index of viscosity from number 35 – receive limiting temperature прокачиваемости oils. For example, oil 10W-40 (the summer index of 40 roles does not play) keeps fluidity to-25 degrees on Celsius (35 – 10 = 25).

The rule 35 is ideally applicable to mineral water, but, unfortunately, approaches for a synthetics estimation – at it absolutely special vjazkostno-temperature characteristics a little. So, for example, class synthetics 10W-40 can be calculated and on-50. In general, synthetics is always colder some mineral water of the same class of viscosity, therefore with it to be mistaken (and to freeze) it is almost impossible. Quality. In our market it often specify on the American scale API. Oils share on a category: S – for petrol engines and C – for diesel engines. If oil universal (suits both that, and another) it is designated by a fractional index where in numerator – preferable type of the engine. Following for S or C the letter (or the letter with figure) means actually quality of oil. For today the best on API are petrol oils of degree of quality SH and SJ; diesel – CG4 and CH4.

Europe now even more often uses a new scale of quality – ACEA. On it petrol oils are designated by letter A (the higher on quality – A3), and oils for automobile diesel engines – letter B (the higher – B3).

Some councils. In the worn out engine where in a finger through which in картер fuel gets, oil viscosity on a class above the recommended is better to pour backlashes. Similarly – if the engine is inclined to overheating. The class of quality of oil for any motors new and old, should be not below stipulated in the service book. Above – it is possible (therefore we and have specified only the higher classes).

And the main thing. Buy oil only in shops with good reputation. Our wild market abounds баландой in the beautiful jars, made it is not known where also whom. Do not peck on the cheap is tempting. Free cheese, as it is known, happens only in mousetraps

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