Dave,

When I was doing my rust repair, i don't recall seeing or removing an air duct that reaches as far back as the front door jamb. Perhaps this fell off or was removed by the PO. I'll have to check back in my pics log to see what it might've lookedl ike.

Re oil additives, thanks for your opinion/advice. I plan to flush the oil by the end of the month and seeing your advice gives me more urgency to do so.

Check list: that was one of the things that convinced me to buy a 87 300DT. I have your website bookmarked as well. This car is really growing on me. Thanks for all the info and help you provide to everyone over the years.