hey o and thanks for reading.

so it started getting cold here in Missouri. i just got back from a trip to CA and while i was gone it snowed here and dropped to 40's and 20's (night and day). i thought my car might be hard to start - its my first winter with a diesel. however it started fine and ran fine. no problems at all during the three hour trip from the KC airport. the next day i went to meet someone to rideshare to work. we took his car. no problems getting going that morning either.

When he dropped me at my car at the end of the day (in a supermarket parking lot) i started it and cranked the heat and then went inside the store. when i came out 15min later my temperature gauge was up to 110 and the cabin was still cold. i'd never seen it go this high. i was concerned about driving it, but considering that i had a little room left on the gauge and a short distance to travel i decided to take my chances.

within a half mile of leaving the store my temperature gauge dropped. rather suddenly, and simultaneously heat started pouring out of the vents. ah that moment felt good. but one other time within the next two miles to my house the temperature started climbing and the cabin air turned cold. then it would suddenly reverse to normal.

so what's going on? this just started yesterday. i drove a little today and the problem was still there, though possibly worse.

water pump? thermostat? not enough coolant in system vs water (summer mix).

any insight would help. thanks for your time and interest.

jeff

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1984 300D "Brown (and Blue) Betty" Over 200k but the odometer isn't counting