The Dodge Challenger Message Board

I have strange problem with my 318. With original radiator engine was overheating, i have installed 26 inch aluminium radiator and Derale 19 inch fan. The termostat is 180 deg, new one and also HD water pump.

Now the engine reaches teh desired temp at the idle but when i start to drive it temp drops to around 55-60 deg C (131 - 140 F) and stays at this level when i drive outside of city with steady speed, even in the city temp is going down as soon as i start to drive.

I am using very nice billet specialities waterneck (no leaks anymore) but i have found that termostat is moving inside it, when i take our the water hose i can lift it like 1-2 mm. Maybe thats the reason? I ma confused and do not know what to do. Mazbe i should switch to electric fans.

Any suggestion will be highly appreciable.

The idea of the thermostat is to hold the water in the engine block and only let it flow to the radiator at the operating temp. This hold the temp at the thermostat rating (180 degrees).

If water is allowed to circulate then it can be cooled too much.

So you were right to think that a loose thermostat is going to be the cause.

It must be the wrong size or there is something not right with that fancy water neck.

T-stat housing. That's my diagnosis.

Problem resolved. I installed higher thermostat opening 88 deg C. and now temp keeps steady around 80-90 deg C. Thanks for your advices.