NEW DATA!!!
So to run the test that blackdawg suggested was not trivial for one major reason...I don't own any gasoline powered cars. Diesel is just fundamentally superior, no?
So after work today I hired someone with a gasoline powered car to come over and allow me to attach a sump pump hose via duct tape to their tailpipe (this is just minutes ago.) My coworker has a honda civic with a tailpipe that's around 3/8", so it worked very well.
So one final time we ran the test without the supplemental exhaust and there was absolutely no color change. Then added the exhaust and within a minute or so, sure enough, turned yellow!!!
While this is bringing me bad news, I'm actually really happy about it because it is confirmation that the diagnosis is correct. Now I get to go into work tomorrow and have everyone say "told ya so" but that's alright.
Now, the question remains is this because diesel exhaust is low on emissions or is it because I've got a dropped cylinder that's just pumping air and no exhaust into the cooling system. I meant to snag the IR thermometer from work today to run 79 Jasper's suggestion, but I forgot.
Any other ways to figure out WHICH head gasket to pull? Otherwise I'm going to default to it being cylinder #1 which had 30psi lower compression than all the others. Thoughts?
