240sx with overheating problem. CAN ANYONE HELP!!

[mikefromtjs]

My 1990 240sx likes to overheat. I canged the thermostat and the coolant to no avail. Any suggestions?

[Morgs]

did you burp the radiator sufficiently when you replaced the coolant and stuff?

[480sx]

I think what this guy means is did you bleed the air out of your coolant system lol.

Jack up the front end and run the car with the air bleeder screw out, and the radiator cap open. This typicaly does the trick.

[Chukidori]

My 1990 240sx likes to overheat. I canged the thermostat and the coolant to no avail. Any suggestions?

What are the symptoms.

Does it over heat if you just let it idle??

Does it always overheat when you drive it a short distance from your house?

Try letting it idle for several minutes with the A/C on after it reaches normal temp, and see if it overheats.

If it does, feel both of your hoses the top one will likely be burning hot, but the bottom one should be warm as well, if its NOT you have a circulation problem.

This bould be cuz ur t-stat isnt opening due to 1. Its bad 2. an air pocket or something is locking it.

or ....your water pump is bad. You can also leave the cap off and see if the thermostat opens when the car reaches normal temp. a PROPERLY flowing cooling system will be very noticible. The water in the radiator will flow like a river, and shouldnt come out of the cap.

if water is coming out of the cap it just means the water is heating up, and being pushed out, not that its flowing.

So check those things.

More than likely you have an air pocket ^_^. These cars are notorious for developing them and you need to fill the cooling system properly.

Since you put in a new thermostat, you need to bleed the system because you let air in.

So yeah, jack the front of the car up, you want to get the radiator ABOVE the engine as much as possible (air always finds the highest point) Leave the cap off, and let the engine run and reach normal operating temp. Check to make sure water is flowing at this point IE thermostat is open, and then let it run like this for a few minutes to push air out of the system.

Recap it and try it out.

[90nissan240sx]

radiator... or water pump...

[Chukidori]

radiator... or water pump...

Dont be so quick to assume...he hasn't even told us the details. The thermostat he bought could be bad, he could have air pockets, he could have debris and rust deposits obstructing flow too.

We dont even know how severe the over heating is. :-/

To rule out the radiator as a catastrophic failure...you could undo both hoses from the engine, cap the radiator and shoot pressurized water or a hose through the top inlet, and see if a respectable amount comes out of the bottom hose.

[mikefromtjs]

aight guys here's the deali let it sit and idle for like 20 min. and nothingi drove it and let it sit and it got a little hotter but nothing happened.the fluid is not flowing through the radiator.when the car does overheat it reaches the "H". yeah. it gets really hot. umm... clearly not the radiators fault. the thermostat i bought through the dealer and they installed it. I don't think that's the problem. i'm thinking there's some crap or an air bubble or something before the thermostat causing it not to open. any thoughts?

[Morgs]

yeah lol thats what i meant, sorry was a little drunk when posted

Perhaps let it sit for longer then 20 minutes? I usually jack up the front end and let it sit for quite a while, just to be sure.

[Chukidori]

If water isnt flowing through the radiator

1. Your thermostat isnt opening2. Your radiator is clogged3. Your waterpump has failed. <==u can get duralast ones for like 23$ from autozone.

[mikefromtjs]

yeah after i let it sit i drove it for like 5 or so minuets then let it sit for another 10 min. Have any of you guys had this problem and if so how did you fix it?it doesn't look like my thermostat wants to open even when my car gets hot. i cant figure this one out.

[S13psi]

since you live in cali, you can get away with just removing the thermo altogether. if this fixes the problem, you're good, if not...

[youngun21a]

Have the same problem,bottom hose cold upper hot,change the thermostat same thing cold and hot hose,so I thought it was the thermostat,hear some termo are defective so I bought two different termo, tryied them both same thing,water pump work,no white smoke,run with out thermo does not overheat till and hour or so in stop and go traffic.and the water level sims low,but don't see water under car or heater core, Can't run it forever with out thermo. I notice something the heater core top hose is hot and the bottom warm,think there is a flow problem??

[180fan]

you have a blockage somewhere or your water pump is not moving the coolant.

[youngun21a]

water pump works,open radiator cap and the the river,flow with no Thermostat,put thermostat back on it over heats,I flush the radiator water flows right out.also notice something but maybe it's just me,when I don't have the termo,water seams to fill up the reservoir tank,but don't see the water on the tub,when I have the termo on tub filled with water and coolant.Fan clutch works,last thing to check is radiator cap,new thermo,the 2 hoses on the back of engine,the ones that go to the heater core.If the heater core works fine,then the two hose would be hot to the touch,right but seams to me the only one hot enough is the top one and the bottom just warm,seams to me i just might just answerd my on ?