A few days ago I drained out some of the summer coolant from the TR3 and added antifreeze because the winters here are quite brutal and I do not have a heated garage. Went for a few drives and checked the antifreeze level and it was way down. I checked the oil level and it was way up!!! I've seen this before on older vehicles I've owned and I suspect I've got a blown gasket. Usually you can tell if there is antifreeze in the oil because you get a "chocolate milk" looking mixture in the oil. Hard to tell if this is the case because I run 20W50 in the oil and when STP is added it tends to make the oil look blacker than it should be. I guess the cylinder head will have to come off but are there any tests or advice before I do that?