My engine keeps on overheating.

[HI NRG]

Hey guys I hope that you can help me out. My engine keeps on over heating, I replaced the water pump and removed my heater core and plugged up the lines that went to them. For some reason when I bleed the system all I see coming out is steam and no antifreeze (well not antifreeze but water). Funny thing is that the top radiator hose is hot and the bottom raiator hose is cold to the touch. OH and I also replaced the thermostat. I know that my thermostat is working cause I did a heat test in boiling water to see if it opens and it opens. When the car overheated I took the bleeder screw out and the temp went down to normal operating temp. Could it be that I am using straight tap water with no antifreeze.Please guys help me out.

[Structure240sx]

your should let the engine cool completely. jack up the front of the car, this will get that air to raise to the top of the radiator. fill with coolant/water combo. once its full start to squeeze the radiator hose to try and get any air in them to come out. continue to fill with coolant/water until its full and put the cap back on. start the car and let it run for a couple seconds. turn it off and start over to make sure all the air is out.

[bruinbear714]

If you installed the water pump and thermostat correctly, and bled the system and it's still overheating, it could be your headgasket. Do you see oil pebbles in your coolant system?

[MikeMurphy]

Could it be that I am using straight tap water

Use distilled water, NOT tap water.

How do you know your overheating?

[NateDogg]

I had the same problem and also put in a new thermostat. Prior to the problem I had replaced the water pump but didn't bleed the system properly. Follow Structure240sx's advice to the tee, that's how I fixed my car.

[574-240sx]

The bleader screw helps too. KA24DE are a pain to blead. It takes me a few times to blead out all the air in my system.

[HI NRG]

Thanks for the help guys....Drove the car around town and for some unknown reason the blow off valve hose fell off while I was punching on the gas and forgot to look at my boost gauge and to make a long story short I blew the headgasket. HA HA HA GRRRRRR.

[Sijonda]

well I'm having a similar problem. I have a 91 240sx. it's been overheating since i got it. I've replaced the thermostat and the radiator cap to see if this fixes the problem. One thing I'm wondering about is the fan shroud, since mine is missing.(cold start) The temp gage goes from cold to dead center and sits there, then after about a minute the gage tops out. I'm sure its correct since when I turn the engine off afterwards I can hear the coolant boil in the radiator and the reserve is full up to the overflow. I'm thinking the radiator isn't cooling the coolant fast enough "hence the missing shroud" I'm wondering if that shroud would make that difference.

[NateDogg]

A shroud will not prevent a car from overheating at idle. Sounds like you may need a new radiator. I tried everything under the sun but my 15 year old rad was just too tired.

[Florida240sx]

He said he plugged his heater core hoses.... Iwas under the understanding that you couldn't block them off.... you just run s small hose between the 2. Otherwise you won't have flow.... Do I have a misunderstanding??

[Sijonda]

so replacing your radiator fixed the problem??? if thats it I might as well let my 240 sit until I got the cash for an SR20.

[lrb_2000]

Thanks for the help guys....Drove the car around town and for some unknown reason the blow off valve hose fell off while I was punching on the gas and forgot to look at my boost gauge and to make a long story short I blew the headgasket. HA HA HA GRRRRRR.

How'd you blow a headgasket by the bov not being connected? Do you mean your wastegate?