Engine Oil - Any problem using a slightly different grade?

[MULLEY]

My TXD is due an oil change as its on 156k, i usually use mineral 15w40, but found some nice Castrol Diesel 10w40 in the garage today. Would there be any issue in using this instead bearing in mind the mileage & what i've been using before? When i originally got the car i was using 10w40 semi, but changed as it was cheaper.

[Kitch]

I predict you will notice no difference whatsoever.

[mat_fenwick]

It'll be the same viscosity once up to temperature (the 40 figure) but a little thinner when cold so theoretically easier cranking. Doubt you'd notice any difference though!

[MULLEY]

Sound, wasn't sure when high mileage might be an issue with using thinner oil.

[Way2go]

It'll be the same viscosity once up to temperature (the 40 figure) but a little thinner when cold so theoretically easier cranking. Doubt you'd notice any difference though!

Yes, some additional info on that....

The first number, which is always followed by the letter W, describes the low temperature behavior of the oil at start up while the second number describes the high temperature behavior of the oil after the engine has been running for some time. Lower SAE numbers describe oils that are meant to be used under lower temperatures. Oils with low SAE numbers are generally less viscous or runnier than oils with high SAE numbers, which tend to be thicker.

For example, 10W-40 oil would have a viscosity no greater than 7,000 mPa s in a cold engine crankcase even if its temperature should drop to -25 ? on a cold winter night and a viscosity no less than 2.9 mPa s in the high pressure parts of an engine very near the point of overheating (150 ?).

[mds141]

I stick Total Quartz 7000 10w/40 in the valver and the XM. It's £16 from the local motor factors.

[MULLEY]

I usually buy mineral 15w 40 Wilkinsons 5litres for £11, bargain But i bought this Total even cheaper off e-bay from someone who wasn't too far away, i think i paid £8.

[rutter123]

i always use castrol GTX or similar 10/40 good quality oil, but have found recently that the containers only contain 4 litres of oil not the 5 litres you would normally expect, dont get caught out and have to buy the extra litre like i had to, moreso if your changing the filter aswell. Cheap oil is cheap for a reason-less protection, and will prob burn more between changes. my tzd turbo has always had a good quality oil in it and never needs topping up between changes and now on 268k and sweet as...think its worth spending the few extra £s and know what your getting rather than chucking in any old recycled/reconstituted cheap crap that i wouldnt put in my lawnmower. if your budget is tight then the oil GSF keep is of reasonable quality and reasonably priced £14 ish 5 litre.

[MULLEY]

I've heard various views about oil quality, but these day's modern oils are so much better than they were 20yrs ago when my car 1st hit the road, they are overspecced for the design, so even cheap oil is better than it was all those years ago, so nothing to worry about. But whatever works for folks, fair do's. I checked mine, its deffo a 5litre one as it says 4litres plus one litre free on the side. Its annoying when you pick up some oil & then realise there is just 4 litres, totally useless in my book.

Never had a problem with Wilkinsons oil, the spec seems fine to me, & dare i say i regularly use non purflux oil filters, the shame of it all....

[Dollywobbler]

I'm with you Mulley. Unless you're running two engines side by side on different oil but otherwise identical use, it's hard to say whether expensive is worth it. Given how tough PSA engines are, 268,000 miles isn't much of an issue whatever oil you use. As long as you actually change it at least when stated by the manufacturer.

[Mothman]

I tend to put a different oil in the MK 1s. just tried Halfrauds and got a type meant for engines built before 1986 and stuck that in. Both Sophie and Gloria seem to run ok, havnt done Mollie yet as i havnt got her running as well as she should as yet.

Andy

[Way2go]

just tried Halfrauds and got a type meant for engines built before 1986 and stuck that in.

Shopping at Halfrauds is a wallet raping experience! For the price of 1 litre of LHM for instance you can buy 3x 1L at GSF. Other fluids like anti-freeze, oils etc (make for make) are also higher for the same price than MDC. The car battery I bought would have been twice the price at Halfrauds.

Presumably "a type meant for engines built before 1986" is just a mineral multi-grade rather than a semi-synthetic or fully-synthetic multi-grade?

It seems their brand loyalty still draws customers in but for how much longer when other big names like Comet are falling by the wayside?

[mds141]

Halfrauds only makes financial sense if you've got a trade card. Batteries, wiper blades and tools attract a sizeable discount. Paints and oils slightly less so. I tend to vary between main dealer ( parts man gives a 20% discount ), Halfrauds and local motor factor.

[Mothman]

Probly true, dont get LHM from them but from the guys who i buy and service my chain saws, bloody cheap from them. They do the oil too now so thats where i will be getting it from as i get a 25% discount.

Andy

[Mothman]

And of course Trago Mills, cant get the stuff any cheaper than them anywhere in the country.

Andy