best oil for my 3.4l c2 at 92k should i go thicker and what brand is the best

[leamus_123]

what brand is the best what thickness ect and how much will i need for an oil chgange my car is a3.4 c2 and done 92 k cheers people .

 

[devans]

I also have a 3.4 c2 with 93k on the clock. Was still using 0w40 until a recent service where i was informed going to 5w40 would be better. The technocal experts will let you know the capacity

 

[steveoz32]

My cars lived on 5w40 until just over 100k and is now running on a Mobil 10w40 oil. I wasn't going to change, but after speaking to Hartech and and Autofarm following their advice and taking into consideration how well they know the inside of higher mileage engines it made sense. You won't find any 10w40 on the approved list though for 996's, so if you have a warantee you'll need to have an oil on the approved list put in at service time.

You'll need to purchase 2x 5 litres for an oil change.

 

[jetbox]

Using 5 or 10w40 oil is only increasing viscosity at start up when cold and is not giving you a thicker oil when the engine is hot, is this the desired effect on an older engine? I thought you needed a slightly thicker oil at working temp?

Confused.

Jetbox

 

[steveoz32]

This is in theory true yes.

Engine wear does occur when started from cold and the oil has drained down, there are two schools of thought here:

A) Having a thinner base oil to move quickly around the engine and circulate faster thus protecting components at a critical time

B) Having a thicker base oil to provide more protection when cold (I would not imagine a 10w40 oil would significantly decrease circulation time vs 5w40)

With something like a 10 weight oil you're only marginally increasing the thickness when cold. You should probably find 10w40 has a higher shear point though, as a multi-grade the viscosity between high and low temperatures does not vary as much as say a 0w 40 or 5w40 and will stay in grade better (and probably a little thicker).

I am far from an expert, but I've used 10w 40 in many cars both new and old, and never had any issues. The debate only cropped up when I saw that there are no 10w40's on the approved Porsche list and I wondered why. Inevitably though older higher mileage engines will have increased tolerances and wear - I would rather have a slightly thicker oil to help mitigate additional wear during critical times.

*edit* I just had a scary thought and was contemplating engine wear as a whole and the amount of time an engine runs. Using my car and my situation as an example, my average speed is 40mph, that comprises of around town and a run on a dual carriageway of 30 miles each way to and from work at about 75ish. Lets use 110k, if you took an average of 2000rpm (allowing for tickover, normal acceleration up to 2.5k, cruising @ 3k, enthusiastic driving and sat in traffic @ zero for one third of my journey) . At 120,000 revolutions per hour, and a running time of 2750 hours, thats 330m revolutions???