Temp guage drops when passing on highway

[BrianinCleveland]

I replaced the thermostat on my 2016 connect with a gas engine.  I went through the process of starting, stopping, filing the resevior tankm to bleed the cooling system.  The heat works and the temp guage stys constant until I step on it to pass on the highway.  When I do this the temp guage drops then goes back to the correct temp.  If I plug in my diagnostic tool to the van, the collant temp goes form normal 180 something to 170 something when the guage drops.  There are no leaks that I can find in the cooling system.  It almost makes me think there is an air pocket in the system that has not worked out yet, has anyone seen or had a problem like this?

[Willygee]

Let the pundits chime in but your connect may have whats called "reverse cooling system". Bleeding procedure typically different. Does sound like an air pocket though.

[BrianinCleveland]

I double checked for leaks and found nothing.  I also have noticed the temp drop only happens when you floor it on the highway.  If you put the RPMs around 4K, nothing happens, if you put the RPMs around 5K the temp drops then recovers quickly when the RPMs drop.  Since the guage and my dianostic tool say the coolant temp is fine until its floored then only drops temorarily, I figure its ok to drive from Ohio to Florida in a few days, hopefully any air pockets will work themselves out on the trip.

[Willygee]

I have a 2016 TC. Neighbor has my scan tool but I will watch the temp gauge between four and five k and see what happens.

[Willygee]

Checked my temperature gauge for dropout but it remained steady throughout all RPMs. Couldn't post results because forum was down.