15w or 10w?

[RugbyPete]

I'm going with castrol gtx next, after good feedback from bobs oil website forums on a good dino oil.

What weight should i get? I was going to go for 10w40 after getting bad economy on 5w-30 (why, i never found out)
but recently read that 15w-40 would be better, as the oil is less stretched between 15 and 40, opposed to 10 to 40 that has to work harder to hit each grade

What say you, 15w or 10w? bearing in mind the recommended is 10w-40 for my car

Also, castrol high milage is supposed to be 'thicker' whatever that means in real terms. now i've hit 100k should i look to this?

ta

[You See]

I run Castrol Magnetec (10W-40) in mine with no problems, I also add Pro-ma which is an additive to reduce friction and help improve your oils performance.

[I-S]

What weight should i get? I was going to go for 10w40 after getting bad economy on 5w-30 (why, i never found out)
but recently read that 15w-40 would be better, as the oil is less stretched between 15 and 40, opposed to 10 to 40 that has to work harder to hit each grade

It doesn't work that way. 10W40 or 5W40 are better choices for the galants, particularly given the behaviour of the tappets at cold start.

What say you, 15w or 10w? bearing in mind the recommended is 10w-40 for my car

Halfords are currently selling 10 litres of 5W40 "fully synthetic" for £31.99. I've been using this stuff to clean out my engine (ie at the moment I'm changing oil at less than 2k intervals to get large amounts of carbon build-up out - kieran will attest to what oil that had been in for 1500 miles looked like when I took it out yesterday) and for the money it's really very good. I put some in my old GLS too.

Also, castrol high milage is supposed to be 'thicker' whatever that means in real terms. now i've hit 100k should i look to this?

Don't bother. In the days of yore, a thicker oil in the later years of a car's life was beneficial. However, with modern engines there's really no need - 100k is not that big a deal to one of these engines.

[Nutter_John]

100k miles is just worn in , my vr4 has 169k and use the best oil AMSOIL

[Paul Beazer]

Im using Mobil 1 0w-40 in mine with no issues for a couple of years now.

[amsoil]

I think you will discover that GTX in the USA ia a very different beast to over here; the same applies to Mobil 1.

[Paul Beazer]

I think you will discover that GTX in the USA ia a very different beast to over here; the same applies to Mobil 1.

Elaborate please Don! You've got me worried now......

[amsoil]

Here's the official reply from Exxon Mobil:-

'All Mobil1 motor oil formulations are different, especially motor oils
that are in different countries.

--
Thank you for choosing ExxonMobil products.
If you need further assistance, please contact ExxonMobil at 1-800-ASK-MOBIL

-Matt Jacob '

Similarly Castrols GTX is I believe a far superior product in the USA than what is available here. Its not made easy for you is it?

I can however state that Amsoil in the UK is to exactly to the same high formula as in the States.

[Kieran]

Each to their own, but I don't understand why you're wanting to put a crappy Dino-oil in your Galant? Don't get me wrong, Amsoil's not your only choice, but castrol GTX? I'd consider it for my coupe with 1970's engineering tolerances, but for a 6A13?

Having just checked, Castrol themselves don't recommend GTX for a Galant V6.

[eclipse97526]

i been running mobile 1 high performance 5w-30 is that bad ? should i go to 10w-40 ?

[amsoil]

i been running mobile 1 high performance 5w-30 is that bad ? should i go to 10w-40 ?

No that sounds correct to me.

[RugbyPete]

Each to their own, but I don't understand why you're wanting to put a crappy Dino-oil in your Galant? Don't get me wrong, Amsoil's not your only choice, but castrol GTX? I'd consider it for my coupe with 1970's engineering tolerances, but for a 6A13?

Having just checked, Castrol themselves don't recommend GTX for a Galant V6.

After much research into oils, people can find themselves OVER compensating with their choice, changing high quality synthetics too soon, inefficiently. People run engines for years on dino, to the end of the cars life, you'll be hard pressed to find a car owners who was left by the roadside because oh damn they chose Shell over Havoline

With so much else on the car with such smaller tolerance and lifespan, the engine at the end of it, wont be the main reason my car fails. Our audi 80, with 360,000 on the one engine with no regard for a brand of oil and before synthetics existed, is testament to the fact oils do there job, a lot more than we think they do.

Changed often, cheap dino oil still has its place in the market, I just want to make sure I'm using the right grade for the application.

[I-S]

Not so sure I agree... modern engines run at higher internal temperatures than older engines do. This causes dino oil to break down into tar which stays in the engine - coating itself on the insides, known variously as sludge, varnish and the black death. Synth and refined base semi-synth can cope with higher temperatures.

Where I can agree is that perhaps people change synthetic more often than necessary - but then it's a question of why it is being changed. It might still be fine as a lubricant, but it might also be carrying all sorts of gunk out of the engine when it's removed.

If you want decent, cheap oil then I'm going to stand by my recommendation of the halford's 5W40 "fully synthetic". For £16 for a 5 litre bottle, it will take some beating.

[Kieran]

People run engines for years on dino, to the end of the cars life, you'll be hard pressed to find a car owners who was left by the roadside because oh damn they chose Shell over Havoline...

I disagree. Let's take the Ford CVH engine as an example. That engine was notorious for sludging itself to death - unless a good quality oil was used and it was changed on the dot, it soon died on it's ass. And I use that as an example, there are many more contemporary units with the same sludging issues (see here: http://en.wikipedia.org/wiki/Oil_sludge)

The root cause is nearly always that the oil has been stretched beyond its capability - either by poor design, negligent servicing or whatever. Sure, all oils have a point where they break down, but it's well known that mineral based oils can't take as much stick as synthetics.

Our audi 80, with 360,000 on the one engine with no regard for a brand of oil and before synthetics existed, is testament to the fact oils do there job, a lot more than we think they do.

But the engine in your Audi is different to your V6, is an older design (correct me if I'm wrong on that, but most of the last Audi 80s carried the same engines from the 1987 'new' shape to the end of production?) and therefore has different requirements. Using your logic, Our Golf Diesel is just about to tick over to 100,000 miles with not a sniff of synthetic bar one change in sight, so by rights I could therefore put Duckhams 20/50 in the VR-4, no?

Of course not, that would be absurd. The engine in the Golf is a a crude, cast iron non-turbo donk that can trace its origins back to the early 80s MkII golf unit and probably earlier still. Same with our coupe; the engine in that has done 90,000 miles in 32 years. Synthetics didn't exist when it was built, But then, just like the golf, it's a crude, basic engine with tolerances to match and no real requirement for a synthetic. Granted to a lesser extreme, but that's the case with your Audi as well.

Changed often, cheap dino oil still has its place in the market, I just want to make sure I'm using the right grade for the application.

Then I suggest you bin the idea of using Castrol GTX - as I've already mentioned, Castrol themselves don't recommend it for the V6. Dino oils do have their place, I agree, but not in a 6A13. They suggest Castrol Edge 0w-30 as a preference or Magnatec 10w-40. See here:

http://www.ew2.lubesinfo.com/login.asp?sc=1156

If that doesn't appeal to your budget, then Isaac's suggestion above is also a good one.

[amsoil]

I must say that I never cease to amazed that anyone can spend a number of thousands of pounds on what may be their largest or second largest purchase to buy a car that is less than economic (but might be more than fun) just to cut corners on the oil which is the lifeblood of the car. If you need to save money on your money burner then use a long life oil from the likes of Amsoil, mobil or one of the other top companies. Forty years ago people used mineral oil because there was no alternative, engines where built accordingly and my mothers escort was worn out at 80,000 miles. Times have indeed changed, To waste the worlds natural resorces needlessly because of stuboness to accept new technology (and of course the Multi Nationals are pleased not to put you off of doing) is IMHO utter madness. When you then work out it costs you money too.....

[RugbyPete]

Not so sure I agree... modern engines run at higher internal temperatures than older engines do. This causes dino oil to break down into tar which stays in the engine - coating itself on the insides, known variously as sludge, varnish and the black death. Synth and refined base semi-synth can cope with higher temperatures.

Where I can agree is that perhaps people change synthetic more often than necessary - but then it's a question of why it is being changed. It might still be fine as a lubricant, but it might also be carrying all sorts of gunk out of the engine when it's removed.

If you want decent, cheap oil then I'm going to stand by my recommendation of the halford's 5W40 "fully synthetic". For £16 for a 5 litre bottle, it will take some beating.

good tip on the synth

And remember, some engines may run under different pressures and temperatures now, but the oil standards have also increased to a superior level - all relative.

[I-S]

It's a 2 for 1 deal, so it's £32 for two 5 litre bottles. I've one or two more left, to get my engine cleaned up and then it's getting amsoiled

[Rambaud]

It's a 2 for 1 deal, so it's £32 for two 5 litre bottles. I've one or two more left, to get my engine cleaned up and then it's getting amsoiled

Likewise - although I may use Amsoil in about 1,000 miles (making a total of 2000 miles since the last oil change), as the current oil does not look too bad at the moment.

[RugbyPete]

placing an order for Motul 6100 10w-40 semi-synth, as the synthetics added are quality. £17 is a steal