Pushing water out of overflow bottle

[install]

I have a 2000 500 magnum 4x4, The other day while out riding it started pushing steaming water out the overflow bottle. the fan or over heat lamp never came on. After looking at and deciding there was nothing I could do there I turned back. after a little while it stopped pushing water out and seemed to run fine. After about 10 to 15 mins of riding the fan finally kicked on flowed by the over heating lamp. Stopped to cool down and made it back safely. However it seemed to have pushed enough water out that it caused it to run low on water and over heat. What should I look at to fix my problems.

[blueline15]

You may have a clog in the cooling system, which meant it couldn't get the proper circulation, the coolant became to hot and expanded out of the overflow bottle, which didn't cause it to trip the fan or temp light because of the clog.

Just one scenario. I'd run it without the radiator cap on to see if you see the coolant flowing in the radiator. The other option is to try to do a flush to see if that helps.

Thats what came to my mind first.

[install]

Will I did not excatly flush the system but ran a bunch of water though it and then refilled it with antifreeze. went out and ran it and it seemed to do ten times better. Very little water at all came out of the overflow. It was letting steam out the radiator cap. think I could use a new cap. would a bad cap contribute to my problem I had.

[blueline15]

You bet. If the cap can't hold enough pressure, it's going to puke out the overflow bottle until the temp of the coolant comes down, or the system goes dry.

[install]

Will bad news after flied testing her she done better but when I took her out to the river the following day she overheated again. So now I digging deeper. The thermostat had been rigged. They cut out the thermostat and just put the seal back in. The water pump looks new but did not have a gasket, just gasket sealer. So I'm replacing those things and a radiator cap. I'm not going to buy the 25.00 dollar one, It seems I could get a 13p.s.i. from auto store that fits pretty good. I took out radiator and washed it in the sink really well this time and straighten out some fins. Cleaned all fan connections and lubed them with electrical goop. The fan switch looked good no build up or signing of scoring. Do you think there is anything else I should look at while I'm here. I will let you know how all that works when done.
What I was wanting to know is what kind of antifreeze and engine oil do you run?