sblake01 said:

If you were not running a thermostat at all, then I could see a heat build up problem in the cooling system cause by too free a flow.

A 160 thermostat that stays open continously (once the motor is fully warmed up) is much the same a not running a thermostat at all. While the flow is restricted by the opening size as you stated earlier it is still flowing constantly which I think will lead to a heat problem especially in 100+ tempratures.

Believe me, Christopher, I'm not trying to fight with you. It's just that at 55 years old, a lot of this stuff is 'been there-done that' for me. I have run a 160 degree thermostat in California in the summer and have not encountered heating problems because of it. I don't run them now because in the winter they don't allow your heater to get as warm as a 180 degree 'stat does.

SBlake 01,I agree with what you said. I always put a 160 for the summer and a 180 for the cooler months and there is a big difference.

I didn't tell that the engine overheats and it is not the case. There is just a fluctuation of the remperature gauge that brings me to believe that the thermostat is starting to be defective.

I will defenitely replaced it.

The thermostat has been replaced today and the problem is fixed. It has been close to 100 degrees today and the gauge needle has stayed below the middle in heavy traffic and as always with the A/C on.

thanks to everybody who have exchanged on this tread.