This is a weird one.

Coolant gauge started going LOWER while driving at 65mph for 30 min. Pulled over to check it out, by then gauge was like it was a cold engine.

-GW expansion tank is full.
-One of the 2 hoses from engine to radiator is cold.
-Radiator is cold.
-No coolant leaking.
-Oil looks good
-I opened bleed screw on radiator and no air, just coolant.

After stopping 10 minutes I started van and temp came up to normal and radiator got hot. Then a get running a few minutes the temp gauge went back down.

I recently had the entire cooling system renewed, new everything.

I have the rear heater core out and both hoses are plugged 

Ideas?

-Mark
87 Westy

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