Aircooled VW South Africa

Tony Z wrote:do you have an oil temp gauge? That oil might run warm with a stock style cooler.
I am still running that oil in my 2332 but I think it is too thick. I'll be switching to something thinner soon.

I don't have an oil temp gauge. Why do you say it might run warm? While the viscosity is higher than SAE40 or 20W50 at the operating temps these VW engines commonly experience I don't think is enough to interfere with the operation of the oil pressure relief valve to the extent that it would cause less oil to flow through the cooler. As it is this is a single relief case and we switched from the grooved oil pressure relief piston to the earlier solid one to improve the oil pressure right accross the range. I've driven the car pretty hard this morning on a round trip between PTA & Joburg and there was none of the usual signs of elevated operating temps.

For info:
Viscosity in cSt for Castrol oils at given temperatures (Calculated using ASTM D341)
SAE40 20W50 10W60
80°C 24.3 30.1 38.8
100°C 13.5 17.1 23.1



Regards,

You do argue a valid point but you do miss the method by which the oil cooler works in the VW engine.
The oil cooler allows oil to flow through it via pressure relief valves.
i.e. it is pressure regulated, not temperature regulated. This is the reason I ditched the entire stock cooler idea on my 2332 and went with an externally mounted temperature regulated cooler.
The cooler gets oil flow when the pressure drops (warm oil). If you run a thicker oil (60) the pressure remains higher, thus the cooler gets less oil flow. Heck, even running a thinner oil with a bigger pump and/or at higher revs will increase the pressure enough to bypass the cooler.
I will be changing to edge 0W40 or Mobil 15W50 if I can find it.

Tony Z wrote:You do argue a valid point but you do miss the method by which the oil cooler works in the VW engine.
The oil cooler allows oil to flow through it via pressure relief valves.
i.e. it is pressure regulated, not temperature regulated. This is the reason I ditched the entire stock cooler idea on my 2332 and went with an externally mounted temperature regulated cooler.
The cooler gets oil flow when the pressure drops (warm oil). If you run a thicker oil (60) the pressure remains higher, thus the cooler gets less oil flow. Heck, even running a thinner oil with a bigger pump and/or at higher revs will increase the pressure enough to bypass the cooler.
I will be changing to edge 0W40 or Mobil 15W50 if I can find it.

I do understand that. On a 2332cc with a monster oil pump that might very well be an issue but I haven't experienced this on a standard motor...yet... Thanks for the heads-up - I'll watch out since we have upgraded to a 26mm oil pump during the rebuild.