I recently purchased a 95 F150 with a 302 auto, the thermostate houseing was leaking so I replaced the gasket and got an air pocket in the process, I fixed that, but I noticed after this all happened (might have been happening before too I don't know) when I cold start the engine in the morning, the temperature climbs slowly like U would expect but it keeps climbing to the end of the L in normal, then back down to the N, and then settles between the R and M. Is this normal or is it telling me something is gonna happen soon
besides the mediocre power it is running great

 

Did u replace the thermostat when u did the housing? My truck has the same problem some times the thermostat sticks.

 

I did not replace the thermostate, I wish I had though now. But if it was a sticking thermostate wouldn't it do it sometimes and not every time after a cold start up??

 

I think this is normal. It's just your t-stat opening up when the coolant gets to the temp your t-stat is rated at. This is how the engine builds heat into it on cold starts.

 

the t-stat is sticking

 

This is most definitely NOT normal.

I would guess that your t-stat is sticking as well. While you have it open, this is a good time to flush the cooling system out and think about replacing the water pump - cheap insurance, and better than having it fail while you're trying to get someplace.

 

not normal.

something is going to happen soon...

i see a new thermostat in your life.

 

Sorry, I didn't see that he said the temp rose up to the L mark. It shouldn't go that high and then settle into the middle.