well this is the story:
one day i had my car parked and after like 30 min the temp went up(almost to the top) and i went out side and looked under the hood and my resevoir coolant was full...like there was no coolant going thru my engine. so i thought that this my be the thermostat or someting in my radiator. i got a new thermostat and hoses and replaced it myself.
i started the car without the raditor cap on so they air comes out. but at first the temp would not go up and than like 5 min later it jumps to normal, however the hoses were not hot so the coolant was not going thru. the finally the temp started to go up and coolant came out of the radiator cause of the air bubbles. i added some more coolant and no more air came out. i closed the radiator and drove it. the temp was normal wheni was driving but when i stoped for like 5 min the temp went up until the fans turned on and than it went down. than i drove it again and parked it and the temp went up again almost to the top but it didnt go down until i started to drive. Does the thermostat has to adjust or did i do something wrong when installing it? please help. Thanks

 

Kinda sounds like a water pump. How clean is your coolant? If its pretty clean, then more then likely water pump.

 

hope you didnt install the thermostat backwards. if its backwards it will take longer for it to open since the bypass on it is on the wrong side and it will take more heat to allow the thermostat to expand open.

 

I would have said the same thing, but I've found out that Nissan sells the T-stat and housing as an assembly. The T-stat is screwed into the housing with torx screws. Basically isn't fool prof, unless a fool at Nissan assembled it wrong.

Water pumps usually don't stop pumping, they tend to just leak from the shaft seal. There are no moving parts to ware down as far as the pump impeller goes.

Are the cooling fans coming on when your inside temp gauge indicates your to hot? You mentioned the fans did come on at one point, so are they cycling correctly?

You might want to check that the temp gauge in your car isn't malfunctioning. Check the connection to the gauge temp sensor. Make sure it's clean and secure. The sensor for your inside gauge may also be at fault here as well.

 

yes my coolant is clean and i looked for a leak or anything from the water pump, but nothing. i checked the car today to see if it overheats but it didnt. I had the AC on full and it was parked for like 10min and the temp didnt go up. The fans did kick in when i had the AC on but they would not kick in when parked and the AC off. When are the fans suppose to kick in? I have a feeling it is something with my fans like u said and maybe the water pump.

 

I think the fans are controlled by the ECU. You may need an engine coolant temp sensor. It may not be reporting the correct coolant temp to the ECU to turn on your fans.

When the A/C is on, your fans run and you stated your car stayed cool. Thus your cooling system is definately working correctly. Your problem is the cooling fans are not turning on as your coolant temp rises. (A/C off) Do you have hard starts when the car is warm also? Thats a sure sign the engine coolant temp sensor isn't reporting the correct temperature to the ECU. The Haynes manual has a table of values for that sensor. You can check it with an Ohm meter to see if it's within specs.

 

do the fans turn on as soon as u turn on the car? and when do the fans kick in without the AC? maybe the temp hasnt been reached for the fans to kick in.

 

It could still be a pump, depending on what the impellar and the shaft are made of. I replaced the pump in my CSVT because the impellar was some type of plastic, and the rivets holding it on were metal. The two materials heated and cooled at dissimilar rates, causing hairline fractures down the middle of the plastic impellar. Eventually, they would break in half...and there goes your engine (at least in the 2.5L Ford DOHC HO V6, it failed very quickly after pump failure while you were underway). It could also be some kind of air leak that doesn't leak much (if any) fluid, and this might go unnoticed otherwise...

Or maybe it's nothing but your fans running incorrectly.

 

I say it's something to do with the fans, but not the fans themselves. Leave the AC off and watch when (if?) the fans kick in when sitting idle. The fact that the fans kick in OK when your AC is on means that they are OK. The problem will lie somewhere in the ECU and or temp gage. Somehting is not telling the fan to kick in when the car is hot. The sequence goes like this;

Engine gets hot, the temp sensor sends a signal to the ECU saying "I'm hot" the ECU then tells the fans "TURN ON" So, check/replace the temp sensor (for the ECU), then check the connection to the ECU.

Keep in mind, there are usually 2 temp sensors, one for the ECU, and one for you, for the temp gage in the instriuments.

DW

 

but when should the fans kick in? like asap or what. Does it have to get really hot before they do turn on. i dunno what to do. I guess i will check the fans when the weather gets better.( tornados and crap)

 

When your car was acting normally, the temp gage never went above half way, right? So as soon as you see the gage above halfway, with the AC off, check to see if the fans are working.

DW

 

well the temp does not go above half now..it hasnt yet. so i cant really check it. But once the temp does go up i make sure to check if the fans are working. When the thermostat was not working ,as soon as i installed it, the fans did kick in when the temp was high and then the temp dropped once the thermostat started to work, cause u could see the fluid mixing in the radiator when i had the cap off.

 

Hopefully you replaced/fixed the thermostat issue, cause that's not right The thermostat should fully open before the car has a chance to overheat.

DW

 

well i checked it when the temp went up. The car was running for like 20 min and then the temp started to go up. I checked the fans and they were not working and the coolant resevoir was getting more full of coolant. I had the same problem with this before i changed the thermostat and so does my friend in his 95 civic. However his fans do work and mine do not, unless i turn on the AC. You mentioned that it could be a sensor or an ECU. Well, I already had a problem with the ECU long time ago-it fried and the mechanic said that something fried the fuel system part in the ECU. BTW, the ECU is from an auto and my car is stick. Once again thank u for the help.

 

it was a dirty sensor.

 

Which one was it, did you replace it or clean it?

 

YEah, what was dirty? I'm curious as well.

DW