[Michael9]

I'm about to change my 93CSE fpt oil for the first time since purchasing the car. Is there any way of telling what type of oil is already in there?
I will be using a synthetic but if it was a mineral oil previously I'm told there's a chance the synthetic may cause any coking from mineral oils to break up and move. The only information I can see is that at it's last service it had 4.5 litres of "F5000" as the service part number. Can you smell/feel/see if the existing oil is mineral? It seems in good condition, not too dirty or burnt with good viscosity.

 

[Superaero]

I switched my 86 to full synthetic a couple of years ago after many miles on Castrol conventional oil. The armchair quarterback version is that switching to fully synthetic may cause old deposits to be cleaned out of the engine so change the oil and filter at the usual interval for conventional oil the first time you use synthetic as any such extra crud will end up in the oil filter.


I now change the oil every 16,000 km or 12 months on both my 86 and my 97 Aero. The 86 has 290,000 km on it and the Aero has 184,000 km. The 86 uses about the same oil as it always did, a liter or so between semi annual changes (now maybe 2 liters over the year since I don't do the Fall change any more) and my 97 uses no oil, none, nada, between changes.

I use 5W 50 Castrol Syntec which is good from minus 35 C to plus 40 C.

 

[Michael9]

Thanks for that. Turns out that "F5000" is semi-synthetic so I can go to a full synthetic without a problem. Cheers, Michael

 

[Basre]

Ohhhh.. and in seeming contradiction to Poular Lore (internet at least) DO change the filter at the usual 3,000 mile interval.. just cuz the oil can endure longer, in no way implies that the Filter itself can.
It gets dirty early.. Change it between oil changes.. yr motor ..will ..live longer as result.

 

[Superaero]

Yes, many do claim that the filter needs changing at the halfway point. However, the synthetic oils don't degrade as fast as conventional oils so you actually don't need to change the filter any more often than once per year or 16,500 km (10,000 miles).


The main problem with oil is not dirt but degradation and contamination. The modern oil filter is more than man enough to last for a year using fully synthetic oil.

Remember the old days when we changed the oil at 3,000 miles and oil and filter at 6,000 miles? Engines were really dirty then with conventional oil low in detergents and low in additives, leaded fuel and often open crankcase breathers (not all the air burned in the engine passed through the air filter then) but the oil filters were OK to go for two oil changes (kind of like putting dirty socks on after a shower though). Then the manufacturers switched to detergent oils with additional additives to reduce degradation and we could skip the 3,000 mile change altogether.

Then the turbo came in and the oil wouldn't last 6,000 miles so we went back to 3,000 mile oil changes but had to change the filter at 3,000 too.

I believe the synthetic oil and filter change once per year or 10,000 miles works for any car built after about 1980.