overheating.

[breeaad]

My first question is, how do you know there is air in the hoses? Because they are hard? They will feel hard and expanded when the system is under pressure. This is probably a sympton of the temperature. But the radiator cap should control the pressure. Any parts store should be able to test your cap to be sure the spring loaded valve is working properly.

Replacing that thermostat is the first thing I would do!!! In order to control the temp of the coolant, you have to control how much and how quickly it circulates. If it is flowing too fast, it will blow through the radiator before it can cool enough to keep the engine cool. This would happen most at higher RPM's, like you suggested it is happening on the highway. Bonnewagon also had good points about the fan, shoud, and overflow. Be sure your fan clutch isn't bad, and that you have a proper shroud. But I would expect these items to cause overheating at slower speeds rather than highway speeds.

If thermo is replaced, fan and shroud are correct, coolant level is good, and flow seems to be good, I would start looking at timing.

 

[pontiacgp]

breeaad, if it's flowing too fast it also doesn't pick up heat from the engine causing the engine block to overheat but the temp of the coolant will register to be ok...it's overheating and you won't even know

 

[jmt455]

Bonnewagon, breeaad and pontiacgp are correct...it could run too cold OR too hot.

My brain fart...guess I'm too used to Michigan winter temperatures to think about warm weather today.

 

[-83MONTESS-]

I don't know why, but I've been seeing a LOT of bad thermostats, even brand new ones. That's why I test every one by heating it up in a pot of water with a candy thermometer. As the temps rise, you can see when it opens, and more importantly, when it closes. A LOT don't pass this test.

x2. I learned the hard way to buy them 2 or 3 at a time and test them.

 

[pontiacgp]

Bonnewagon, breeaad and pontiacgp are correct...it could run too cold OR too hot.

My brain fart...guess I'm too used to Michigan winter temperatures to think about warm weather today.

I'm north of you but my bicardi black and coke is warming me up just fine...

 

[breeaad]

breeaad, if it's flowing too fast it also doesn't pick up heat from the engine causing the engine block to overheat but the temp of the coolant will register to be ok...it's overheating and you won't even know

Good point.

 

[pontiacgp]

Another factor in controlling the coolant temp is the mixture of coolant and water. If too much coolant is used it can cause an overheating problem. Coolant is only good to keep the water from freezing and raises the boiling temp of water and it lubricates the system. Coolant does not disperse the engine heat efficiently, the water does. In the summer I fill the system with distilled water and water wetter. I only put in some coolant for the winter while the car is parked.

 

[rustyroger]

Another factor in controlling the coolant temp is the mixture of coolant and water. If too much coolant is used it can cause an overheating problem. Coolant is only good to keep the water from freezing and raises the boiling temp of water and it lubricates the system. Coolant does not disperse the engine heat efficiently, the water does. In the summer I fill the system with distilled water and water wetter. I only put in some coolant for the winter while the car is parked.

By coolant I guess you mean antifreeze. It also contains additives to inhibit electrolytic reaction, important if you have any disimilar metals in a conductive solution. Most makers recommend 40-50% solution.
Every water cooled engine on the market should run fine with an antifreeze solution at all times, they are designed to do so. They should also run fine with the correct thermostat.
If your car is overheating and the coolant level and thermostat are ok you have another problem, you need to find and fix it.
In this case it seems to be the cooling system is being pressurised, most likely a bad head gasket, testing for co in the cooling system will soon show it up if that's the case.

Taking the thermostat out or adding extra fans is doing a botch job, fixing it properly is the least expensive way to deal with cooling system or any other issues. Not just cars but any job IMO.


Roger

 

[chevyman454]

anti freeze DOES NOT increase the boiling point of water pressure does, water will boil at room temp under 30hg of vacuum
you may want to check the cap for its proper blow off pressure ( check your service manual for PSI)
also if there is a small crack in the head block or intake you will lose a certain amount of coolant if you are checking the flow of coolant feel the upper and lower hoses and see if the temp is about the same. and clean out that radiator no bugs allowed

 

[pontiacgp]

chevy I know pressure increase the boiling temp but antifreeze does raise the boiling point of the water it is added to...Prestone 50/50 Antifreeze/Coolant has a dual action formula that can provide protection from -86 F to 276 F....or prestone is falsely advertising it for years.