The right Penrite Oils for an 03 1.8 MX5

[sirbob]

SIN 5 is far too light IMO, i used to use Castrol Edge 5W-30 in my NB8A and it's used to turn black very quickly. I then upgraded to Mobil 1 10W-50, and had no issues...

Also Penrite Limslip90 for the diff? I dont know much about Penrite diff oils, but i know that most oils have very different specifications between LSD and open diff applications. I presume you only have a stock rear diff, which will be an open center for an 03 NB. It may well be the case that this is the right oil for you, but i would check the owners manual first to confirm.

In your owners manual you should see both a vicosity rating vs tempreture graph for both engine oil and diff oil, as well as a minimum API grade. This API grade is very important as it determines the actual stickiness/lubrication properties of the oil. The manual should also tell you whether you need a hypoid type oil or not...

In short, read the owners manual, then make your own decision... After all, noone knows the Mazda MX5 better than Mazda themselves...

[sirbob]

Also, on a side note...

Dont trust the Repco blokes... I was helping my brother in law service his BA XR8 and we needed to get some oil. The shop assistant wouldnt leave us alone so i asked him to find out what oil we needed for the car. (Mostly to get rid of him) He returned far to promptly and declared that we needed Castrol Edge 0W-Something...

I then looked up the owners manual for the car and found that the specified viscosities around 10W-20W for this low revving V8. Needless to say i went with what Ford suggested...

[JBT]

Further side note: a TorSen LSD uses normal diff oil, not LSD oil.

Check the owner's manual and get the Penrite oil that matches the specifications recommended by Mazda.