Weird overheating
 

I just got a 95 Toyota pickup and have been driving it a bit. After I start and it warms up it goes past the 3/4 mark for the temperature and then slowly drops down to normal temp and stays there for the rest of the drive. Any ideas on what might be causing this?

It's the way the cooling system is designed. The "cold" water from the heater core in the cab is returned to the system right at the thermostat. It tends to hold the thermo closed longer than you would think it would stay shut. Thus, the gauge goes up high, then drops down as the thermostat opens and allows the hot water in the main part of the system to flow through the radiator.

Toyota came up with a 2 stage thermostat that will stop this effect. The first stage opens at a much lower temperature than the main portion, allowing SOME water to flow through. The main system still warms up and pops the main part of the thermostat normally.

As long as the gauge doesn't go to, or above, the upper red mark, you're in good shape. You might also, BTW, check to ensure the system is properly flushed, and burped. Air in the system can make it SEEM to be running hot. It won't appear to cool down properly though.

Does that help any?
Pat☺

thanks that makes a lot of sense I’m glad to know that what it is doing is normal for the vehicle.

2ToyGuy does have a point, make sure there's no air in your cooling system.

Yeah, but if I wear a hat, noone can see it. The point, that is....
:D
Pat☺