Hey everyone,

Just swapped a d15 for a d16. I'm only having one issue. The temp gauge as well as cabin heat tell me something is up. The temp gauge will go up to normal operating temp, then drops down to the "C" again, again raises to normal, and drops again etc, etc. Also, the cabin heat doesn't get above lukewarm even at normal running temp.

As a note, I've bled all the air out of the coolant lines.

Anyone have any suggestions?

 

Thermostat in the engine housing perhaps. Sounds as if it's stuck open or missing.

 

Yup, I'd replace the thermostat.