When it gets hot, coolant expands, that's what the tank is for. As it cools, the coolant contracts, and gets sucked back in to the radiator.... Top off your coolant, also, might wanna try and figger out where it all went.

 

Coolant alters the boiling pioint of water from 212 degrees to something higher - depending on amount of coolant added. But letting one run at 260 degrees is too high, and although the water may not boil, bad stuff is already happening.

Wafrican, you gotta find out why it gets hot enough to fill the overflow, and then draws it back in, but radiator should be full. There is a way to see if there is oil or exhasut by products in the coolant, which can determine such things as head or head gasket issue.

The water pump impeller can wear, making the efficient movement of coolant throughout the system impossible, which can impair cooling. If the pump has not been changed, this and a new stat may be good places to start. And I agree on the timeing set as well due to the fact that most of the work to get to it is alaready done when pump is pulled.

How do spark plugs look? In most cases, if ther e is coolant in the combustion chamber, there will be indications on the plugs.

 

Hey guys so I decided to try to replace the thermostat today and I really wish I had just left it alone because I can't get the damn thing to seal now. What could be the cause for this? I did use rtv and a new gasket but still cant get it to not leak.

 

gasket surfaces have to be squeaky clean. The old paper gaskets like to stick... and can be a bear to get off. Especially on the intake behind all that crap.

 

Were you towing or something? Also some people will disagree but I know this from experience. Ethylene glycol (antifreeze) helps your engine cool better than just plain water would. However eg will lose its effectiveness after about 2 years under moderate driving conditions. I know that we are towing with our half ton truck today at 100 f actual outdoor temperature under 10 tons of a load, and it was able to stay under 240 without tow package, so it is not like these trucks cannot cool.

 

Just for giggles and grins....check the condition of radiator cap. If it is not sealing well, it will allow coolant to blow out while driving and run low...

 

Ok so I finally got the damn thing to seal and the truck is running as should. The reason I would lose so much coolant was because the truck would heat up so hot that the coolant would expand and overflow the reservoir and when cooled the reservoir would be empty.