engine oil issue

[CMF_andy]

am told that synthetic oil must not be used on a old vehicle as it might remove the carbon deposites on the oil seals in the engine and will cause it to leak.
my micra 1.0 is 10 years old,done 180k.
previous servicing unknown.
is it advisable for me to go ahead with synthetic oil 5w40?
or should i stick to mineral oil 5w40?
what is the difference between the two when the grade is the same.

 

[CMF_Yom]

Just stick to a mineral oil. 5w40 is too thin for your evnironment as well (assuming you live in singapore).

10 or 15w40 will probably be cheaper than 5w40 and will be quite OK for your motor.

A fully synthetic oil will be just asking for problems. Its not so much oil leaks which are an issue - the major issue is with sludge being picked up and moved around and eventually blocking the oil channels and oil squirters for various areas of the motor, usually in the head where the cams can start to run dry and in more serious cases, the big end bearings. A problem with the oil flow down there and you may as well throw your engine out and buy another one!

Cheers

 

[CMF_andy]

recently got my engine flushed with a dupont engine flush machine.
do you think all the sluge had been removed?
or are there still some sticking around?

 

[CMF_Yom]

I wouldn't be counting on it. Better to be safe rather than sorry.

Besides the only reason you should be using synthetic oil to get your hands on that Grade 5 stuff which basically ensures there is no metal to metal contact with any lubricated parts within the motor.

Any other synthetic oil is a complete waste of time and money.

 

[CMF_discopotato03]

Yom what do you meany by grade 5 ?

I realise that some oils are "more" synthetic than others due to a rather large legal battle in the US a while back and a contradiction in defining synthetic .

I think you'll find high detergent oils will move "sludge" though from what I've seen in poorly maintained engines is a varnish like coating on rods cranks blocks etc .

If I wanted to clean an engine that was an unknown quantity I would give it several oil and filter changes in shorter distances ie 500 km .

Cheers DPO3 .

 

[CMF_Yom]

grade 5 is essentially the highest quality consumer synthetic oil available.

Motul, NEO, Royal Purple, etc are all grade 5 oils. And boy do you pay for it.

 

[CMF_Yom]

the castrol "edge" and "formular R" oils arent fully synthetic either. The 0w-** variations might be, but from what I found the rest of them arent worth the price.

 

[CMF_Snoopy]

Beware of Castrol engine oils. They are well known in the trade for sludging up engines. I can always tell when someone uses castrol in there car as sludge is always more than normal. This doesn't apply to any of there other products which are very good.