I know that when the coolant in the overflow tank rises it means there is air in the system right? That is what is going on right now. as soon as the coolant rises if I try boosting my water temperature needle will rise but when i release the throttle pedal my neddle slowing returns to normal. I bleed the system by removing the radiator cap and adding coolant as the air bubbled out.
I do this until I dont anymore bubbles. Yet my coolant in the Overflow tank still rises. I never have to refill my cooling sytem the amount stays constant.
I have a red top Sr, Koyo radiator, stock altima electric fan, I replaced the thermostat, and water pump already.
I have a HKS FMIC, Blitz BOV, walboro fuel pump 3 inch catback connected to stock KA catback. this is on a 1990 240sx
what is wrong? any ideas?
i think I got all the info in, Please help.:help :help
Air in Cooling System?
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SpeedRacer1
- Posts: 3144
- Joined: Fri Jul 26, 2002 7:44 pm
- Car: 1990 240SX, G35
Sorry to jack your thread but this is sort of related. I just changed my thermostat, water pump and rad cap and filled up my new rad with coolant. Problem I am having is it doesn't seem like my thermostat is opening. The lower rad. hose is always cold no matter how warm i let the engine get while the upper hose is boiling hot. Also when everything is nice and hot the top part of the rad is burning hot but the lower is ice cold. I bled the air out and still have this problem. I had it with my old thermostat and same thing after I changed it. Anyone have any ideas?
very common problem.ASSUMING you put the stat in the right way also with a bleeder to the top.
Any air in the system the pump wont work correctly.cavitates.
the hot water has to be pumped passed the thermostat to get it open.On RB engines the water circulates across the block,not the head.with the hot water rising to the top.so when the engine is warmed up the temp would be almost boiling.
front drive N14 had a good bleeder in the heater pipe droped on later models.if the water circulated through the heater ok it was working.you could put a 8 mm hose and pressure feed it.
Any air in the system the pump wont work correctly.cavitates.
the hot water has to be pumped passed the thermostat to get it open.On RB engines the water circulates across the block,not the head.with the hot water rising to the top.so when the engine is warmed up the temp would be almost boiling.
front drive N14 had a good bleeder in the heater pipe droped on later models.if the water circulated through the heater ok it was working.you could put a 8 mm hose and pressure feed it.
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yellow_jacket
- Posts: 1355
- Joined: Mon Jan 13, 2003 4:43 pm
- Car: 95 240sx
There is either air in your system, you got a bad thermostat, or the head gasket is blown.
It sounds like you did not bleed the system correctly. With stubborn air pockets it is best to Open the bleeder, fill the system, close the bleeder, run the motor until the thermostat opens, add any neccesary coolant, then install the radiator cap. DO NOT put it on until the very end. Also, sometime when the car is warmed up, make sure the heater is blowing hot.
It sounds like you did not bleed the system correctly. With stubborn air pockets it is best to Open the bleeder, fill the system, close the bleeder, run the motor until the thermostat opens, add any neccesary coolant, then install the radiator cap. DO NOT put it on until the very end. Also, sometime when the car is warmed up, make sure the heater is blowing hot.
these engine dont like running with out the radiator cap.as the thermostat is on the suction side of the radiator when its close water will be forced out the cap giving the impression that its full.a special TOOL is a radiator cap extender[a pressure test adaptor will do].this allows the air to rise up the pipe.and to see if its working.parking in a steep grade helps.extending the radiator cap up to 14-18 feet will give full pressure.
attatch [clear] pipe to over flow outlet[8 mm] and fit radiator cap with the lower pressure seal removed.throw hose over rafters in shed.watch water pressure changes.
attatch [clear] pipe to over flow outlet[8 mm] and fit radiator cap with the lower pressure seal removed.throw hose over rafters in shed.watch water pressure changes.
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yellow_jacket
- Posts: 1355
- Joined: Mon Jan 13, 2003 4:43 pm
- Car: 95 240sx
All cars will push antifreeze out of the radiator with the cap off. It is nothing out of the ordinary. You don't need any special kit or tools. Just let it flow out and when the thermostat opens the fluid level will suddenly drop, add some til it is full, put the cap back on, and go for a drive.
BTW: It doesn't matter if the thermostat is on the suction side, that is not why the fluid comes flowing out as the car heats up.
BTW: It doesn't matter if the thermostat is on the suction side, that is not why the fluid comes flowing out as the car heats up.
late model cars are not the same as as the tried and proven convection systems.I havnt had loads of experience with 200-240 sx but frontdrive SR and KA and read drive CA,RB/RD can be a worry. but easy to deal with when you do it often.
as the thermostat is on the low pressure side of the water pump the radiator is extra presurised it should be full even when the head is empty. the old common systems,the pump presurises against the thermostat helping with cavitation etc and the radiator is at a lower pressure than the engine.Just notice the Shrinking lower hose when reving.
An rb engine the water is circulated across the block and through the heater.untill the thermostat opens the head and radiator are almost stagnet.so you would have little idea what the true water level is.
very common on europe style cars with bypass surge tanks etc.when the thermostat opens air enters the pump and water thats there boils.
as the thermostat is on the low pressure side of the water pump the radiator is extra presurised it should be full even when the head is empty. the old common systems,the pump presurises against the thermostat helping with cavitation etc and the radiator is at a lower pressure than the engine.Just notice the Shrinking lower hose when reving.
An rb engine the water is circulated across the block and through the heater.untill the thermostat opens the head and radiator are almost stagnet.so you would have little idea what the true water level is.
very common on europe style cars with bypass surge tanks etc.when the thermostat opens air enters the pump and water thats there boils.
robbbby wrote:Sorry to jack your thread but this is sort of related. I just changed my thermostat, water pump and rad cap and filled up my new rad with coolant. Problem I am having is it doesn't seem like my thermostat is opening. The lower rad. hose is always cold no matter how warm i let the engine get while the upper hose is boiling hot. Also when everything is nice and hot the top part of the rad is burning hot but the lower is ice cold. I bled the air out and still have this problem. I had it with my old thermostat and same thing after I changed it. Anyone have any ideas?
hey was this your problem robbbby? because I have the same problem, let me know, asap!