Oil advice anyone?

[nicky.mattsson]

Wow, having a new car is fun aint it?

My next issue is Oil, i have searched high and low for an answer on this but i just cant seem to find it.

I have a MX5 1.8, its got almost 100k on the clock and a FSH but i do not know what oil they used. Will it be ok for me to switch to Fully Sunthetic or shall i stick with Part Synthetic just in case.

Any ideas welcome, cheer.

Nick

[littleredrooster]

Just in case of what?

Part- or fully synthetic, the choice is yours, they can be mixed without problems. Just make sure you change it at the specified intervals (or sooner).

[nicky.mattsson]

Just in case anything really. Ive heard stories and stuff on how you shouldnt put Fully in if its an older car on high mileage or if its only had part/mineral in previously.

[ALawson]

Why not call the last garage on the service history you have, that assuming that you have some. Or failing that just contact Mazda or opioils who have a sticky at the top of Gassing Station

here.

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

[nicky.mattsson]

All i wanted to know if it is a good idea to suddenly switch to Fully Synthetic from whatever is in there now or if it wont make the slightest bit of difference.

[catman]

Although I don't believe that there would be a problem in switching oils normally, I believe that fully synthetic oil may be thinner, which may cause some issues on a higher mileage car with some wear on the engine.

Tim

[Ozzie Osmond]

Modern fully synthetics are very, very good.

The risk is you shove some of it in an old clunker engine and the new oil dislodges old sludgy deposits, leading to oilway blockages and engine destruction. This risk may be small but why take it? It's not as if MX5 engine is "highly stressed" so the best course is to stick with an oil that the engine knows and is happy with.

Good fully synthetic oil = cheap engine insurance. Most of my cars run on fully synthetic at huge expense and I've never had an engine problem, so the xpense causes me no worry at all. On the other hand my highest mileage car runs on mineral GTX Magnatec, has covered over 150,000 miles and keeps going strong....

[busta]

Won't make the slightest bit of difference. Just get the right grade (5w40 or whatever it takes, should say in the manual) but fully synth, part synth, agricultural, tescos value etc won't have any adverse side effects.

I have a 200,000 mile Volvo that gets an oil change every 5k, and has done since the warranty expired, with agricultural spec (cheap as chips, from a 40 gallon drum) oil and has never suffered because of it.

Regular oil changes are much more important than the type of oil used, especially on older simpler engines like the Mazdas.

[Oilchange]

All the cars I've bought have had a selection of oils, of the correct grade I might add, put in. All were fine, in fact the point of having fresh oil is the biggest benefit to the engine, they rev cleanly and run really well. I initially bought the cheapest Silkolene/Fuchs semi synth XTR 10w40 from Opie then went on to fully synthetics etc. All changed at 5,000 miles religously.

[davepoth]

As has been said, change oil often, is better than leaving good oil in for ages. This is especially true on an older engine where you will get more carbon in the oil due to blowby on the piston rings. If anything, consider using a slightly thicker oil than specified, as on older engines the moving parts will have worn a little leaving bigger gaps, for which you need thicker oil.

[s2art]

davepoth said:

As has been said, change oil often, is better than leaving good oil in for ages. This is especially true on an older engine where you will get more carbon in the oil due to blowby on the piston rings. If anything, consider using a slightly thicker oil than specified, as on older engines the moving parts will have worn a little leaving bigger gaps, for which you need thicker oil.

Not necessarily true. People who do oil analyses found that with an oil change there was increased leaching of various metals from the engine. Basically until a new equilibrium was reached. Probably best to use a good oil and change it every 10K or thereabouts, depending on your particular usage.

Edited by s2art on Monday 19th July 00:04

[HellDiver]

I changed from semi-synthetic to fully synthetic on my Mondeo (similar ex-Mazda engine), with no issues to report. Car has 60k on the clock, mostly town driving.

[opieoilman]

If the engine is in good shape then there is no issue swtiching from semi to full synthetic and back again. They will also mix just fine so you can top up one with the other.

Synthetics are not thinner then their mineral cousins, they come in all the same viscosities and more. For the OP's MX5 I would be tempted by a 5w-40 synthetic.

Cheers

Guy

[nicky.mattsson]

Thanks chaps, thats the kind of advice i was after. I beleive the engine to be in good shape, no knocks, noises leaks etc and it has a FSH.

I will probably switch to Semi then move on to Fully in a few changes if everything is ok.

Nick

[littleredrooster]

s2art said:

Not necessarily true. People who do oil analyses found that with an oil change there was increased leaching of various metals from the engine. Basically until a new equilibrium was reached.

Linky? Never heard of that one, even when writing my dissertation on lubrication......

[s2art]

littleredrooster said:

s2art said:

Not necessarily true. People who do oil analyses found that with an oil change there was increased leaching of various metals from the engine. Basically until a new equilibrium was reached.

Linky? Never heard of that one, even when writing my dissertation on lubrication......

Some people on the Rennlist Porsche site are very anal about their oil. They perform used oil analyses and found that there is significant wear initially after an oil change.

'Contrary to common perception, changing oil more often than recommended has been shown to be likely to increase engine wear. Ongoing SAE and University of Michigan studies appear to have shown that the greatest wear occurs in the first 3000km of an oil’s life in an engine!
There are many reasons for this which we cannot cover here but mostly they relate to the anti-wear chemicals used in the old oil’s additive package being stripped away and being replated by the new lubricant'

And;


http://www.swri.org/3pubs/IRD1999/03912699.htm


'Testing with partially stressed oil, which contained some wear debris, produced less wear than testing with clean oil. This finding was unexpected and initially confusing (further inquiry suggested that the result was not so surprising, as many oil chemistries require time and temperature to enhance their effectiveness).'

Edited by s2art on Monday 19th July 21:46