I have a 1970 MGB which, like all North American models of this vintage, has a factory oil cooler. The oil in it now started out as Castrol GTX 20W-50, but in the past year has been topped up with VR-1 20W-50, Penzoil 20W-50, and even some convenient store 10W-40(when you're on the road and need oil, you take what you can get). I will be pulling the engine in the next few weeks, and after doing that will refill with VR1 20W-50. I've been told, although I don't know how true it is, that BMC/BL assumed that a lot of US cars would get 10W-30 and they wanted to be sure the oil pressure was sufficient. In any case, I've been concerned for a little while about my oil temperature reaching their optimum level. Since buying a IR thermometer, I've become a bit more concerned. I'm running a 195º thermostat and, with the exception of very hot days crawling in traffic, the temperature gauge stays put right in the center. I typically measure 200-205º right above the thermostat immediately after a drive. The oil, however, is a different story. I'm getting temperatures in the 160-165º range at the block right above the oil pump on the hose that goes to the cooler, and about 140º coming out of the cooler and into the oil filter. Sump temperatures seem to run in the 130-135º range. My most recent numbers are from last night after about 2h of "spirited" back road driving, but they were in line with these. It's been my understanding from reading here that optimum temperatures oil temperature are somewhere in the 200º range for the additives to be most effective. I'm wondering if I should be doing something to keep the temperature up. As I see it, it looks like I have a couple of options. The first, and least expensive, is to just wire some cardboard in front of the oil cooler. I did this most of last winter, although I never actually measured temperatures. I do know that it seemed to help the engine come up to temperature faster. If I wanted to be a bit neater on this, there is an aluminum blanking plate available that's designed to "snap" around the cooler(apparently a dealer option when new, although someone is making them now). The second would be to eliminate the cooler entirely. While the engine is out, it would be very simple to run a straight pipe from the oil pump to the bottom of the filter. I think the major parts dealers stock these, as many post '75 engines didn't have a cooler at all, nor did the UK market ever have them as standard. The third-and most expensive option-is to install an oil thermostat. These run $400 for the good ones(and I've heard bad reports of the less expensive ones). Any thoughts on any of the above?