Which oil?

Author
Discussion

Kinky

Original Poster:

39,800 posts

276 months

Tuesday 10th April 2007
quotequote all
I'm considering doing an oil and filter change in the coming days.

I'm not sure what oil is in there at the moment and I've no reference to any previous oil used (no engine bay stickers and no previous service paperwork).

I was in Halfords on Monday, just having a nose (and buying a soldering iron) and I was having a look at their 'guides', where it lists the manufacturers recommended oil and their own recommendation, and they both differed.

They also recommended a semi-synthetic,

I've shot an email off to Opie Oils - but no response as yet.

So, question to the floor - which oil is best?

Driving style is 50% motorway and 50% 'fun' roads.

Many thanks in advance,

K

I've also posted this on Moonrakers

DennisTheMenace

15,605 posts

275 months

Tuesday 10th April 2007
quotequote all
I had a nosey through the SH of the car , and its used magnatec 10w/40 for pretty much most of its life , so ive got a gallon of that to bung in it .

Kinky

Original Poster:

39,800 posts

276 months

Tuesday 10th April 2007
quotequote all
Just got a reply from Simon (Opie):

Cost = 10w-40 semi-synthetic
Quality = 5w-40 synthetic

K

thegreatsoprendo

5,286 posts

256 months

Wednesday 11th April 2007
quotequote all
Kinky said:
Just got a reply from Simon (Opie):

Cost = 10w-40 semi-synthetic
Quality = 5w-40 synthetic

K

Can't argue with that. Personally I've almost always used Halfords fully synthetic 5W-40.

nicecupoftea

25,313 posts

258 months

Monday 16th April 2007
quotequote all
Mark at Freelance Mazda in Chatham recommends semi synth as he said the fully synthetic was a bit too thin IIRC.

speedychrissie

2,994 posts

246 months

Tuesday 17th April 2007
quotequote all
this thread seems like a good place to ask this:

has anyone got any tips for removing the oil filter? i am planning on changing the oil soon on my car and the filter at the same time, but i dont think there is enough space for my chain filter removing tool.

have people found a tool that works well considering hte limted access?

franv8

2,212 posts

245 months

Tuesday 17th April 2007
quotequote all
Best tool is a dry ungloved hand.

Failing that get strap wrench (e.g. halfords) - which is a piece of 1" wide fabric/webbing in a loop attached to a 1/2" drive sicket. Alternatively you can make the same thing wrapping string around an extention bar and rotating to tighten round the filter.

But seriously, I'd be very surprised if you can't spin it off with your hand.

Also, apologies if telling you how to suck eggs, to fit the new just oil the sealing ring on the filter and spin on HAND TIGHT - it does not want to be done really really tightly, and you shouldn't crush it whil gripping it either!

thegreatsoprendo

5,286 posts

256 months

Tuesday 17th April 2007
quotequote all
nicecupoftea said:
Mark at Freelance Mazda in Chatham recommends semi synth as he said the fully synthetic was a bit too thin IIRC.

I'm a bit confused by that. Let's compare 5W/40 fully synth and 10W/40 semi synth for example. The first figure denotes the viscosity when cold and the second the viscosity when hot. The viscosity when hot is the same in both cases (as denoted by the "40" figure).

When cold, the fully synth will be less viscous (thinner) than the semi synth as denoted by the "5W" figure as compared to the "10W" figure. But we know that all engine oil is more viscous (thicker) when cold compared to when hot. We also know that engine oil doesn't give full protection until it's reached operating temperature (and has therefore "thinned" ), so the thinner the oil when cold the better. So at what point can fully synth possibly be "too thin" compared to semi synth?



Edited by thegreatsoprendo on Tuesday 17th April 23:23

speedychrissie

2,994 posts

246 months

Tuesday 17th April 2007
quotequote all
franv8 said:
Best tool is a dry ungloved hand.
But seriously, I'd be very surprised if you can't spin it off with your hand.


cheers for that. come to think of it i spent quite a few minutes trying to fit the tool in the space that i didnt even consider the fact that i might be able to remove it by hand!

nicecupoftea

25,313 posts

258 months

Tuesday 17th April 2007
quotequote all
thegreatsoprendo said:
nicecupoftea said:
Mark at Freelance Mazda in Chatham recommends semi synth as he said the fully synthetic was a bit too thin IIRC.

I'm a bit confused by that. Let's compare 5W/40 fully synth and 10W/40 semi synth for example. The first figure denotes the viscosity when cold and the second the viscosity when hot. The viscosity when hot is the same in both cases (as denoted by the "40" figure).

When cold, the fully synth will be less viscous (thinner) than the semi synth as denoted by the "5W" figure as compared to the "10W" figure. But we know that all engine oil is more viscous (thicker) when cold compared to when hot. We also know that engine oil doesn't give full protection until it's reached operating temperature (and has therefore "thinned" ), so the thinner the oil when cold the better. So at what point can fully synth possibly be "too thin" compared to semi synth?



Edited by thegreatsoprendo on Tuesday 17th April 23:23


Don't ask me, I think that's what he said. I may have misunderstood him.

mx-5 lazza

7,954 posts

226 months

Friday 20th April 2007
quotequote all
I always use Mobil 1 0-40 (I'd use 5-40 if I could find any).
I used to get my car serviced at Newbury Mazda who were MX-5 specialists and they wouldn't use anything else on MX-5 engines.
In other Mazda engines they used normal Mazda semi-synth but not MX-5's as they tend to live in the higher rev ranges.

Oh, and Purolator oil filters are much better than Mazda filters or those Halfords sells.

Edited by mx-5 lazza on Friday 20th April 20:27

t40ora

5,177 posts

226 months

Friday 20th April 2007
quotequote all
I use Magnatec. I was given the advice that the fully synthetic is too thin - although mine has done 140k miles.

Still going STRONG though.

cen

593 posts

242 months

Saturday 21st April 2007
quotequote all
Echoed go Magnatech its leaves a thiin film of protection. I once witnessed a test in Cardiff Bay whereupon they drained the oil from a Volvo and replaced with Magnatech. They then ran the engine up to operating temperature and drained. The car was then driven around the bay without any oil and returned ticking over sweetly. Obviously at this point they put the oil back in. The test was simply to demonstrate the thin layer it leaves offers protection.

franv8

2,212 posts

245 months

Saturday 21st April 2007
quotequote all
Chaps - these engines. They were based on the 323 Turbo, and now they're running in a relatively low state of tune (for a 1.6, about 75 bhp/litre for a 4 valve motor) - either the semi or the fully synthetic will have no issue in these engines. Just look at how many people are posting 'I just knocked the bearings out in my engine'

Me - I used to use Magnatec but now use the Halfords, or otherwise, synthtic. Oil pressure always good (unless level is low..........) and engine going strong - about 140000 km's.

Just use something half good and it won't be the thing that stops your 5.