You can add one by using a few adapters and plumbing fittings to squeeze a Tee fitting off your existing port. Sunpro sells adapter kits through catalogs and retailers for about $5, and good hardware stores sell plumbing fittings. You can also adapt off the heater fitting in the head, which is probably pipe thread to start with and thus may need no adapters. Space is tight there next to the oil air separator, but it can be done. I used a Beede gauge from JC Whitney with a Stewart Warner sender. Based on my preliminary testing, the gauge appears to read 30 degrees hot. Most gauges are a bit off. You have to test them.

The Volvo gauge is next to useless because it has no gradation and has a compensating board fitted to it that makes it read in the middle from about 160 to 220 degrees, so the average driver does not worry. By the time it goes right of center, there are likely problems. I do not know whether it is possible to remove the compensator and use Dave Barton's graded gauge face kit.

Philip Bradley