Alright, I really have no clue what is going on with my car. THe problem started last summer and continued over the winter... although the cold weather kept the over heating to a minimum. Now that its warmer, its a different story.

Last night, coming home at about 3am I was doing about 80 on the highway and I look down and holy crap! The temp needle was at 3/4 of the way up! After a run on the highway and stopping at a light, it will go up as well. BUt once the car moves out of a light or traffic it goes down a bit.

I have flushed the coolant, changed the radiator, new thermostat, new water pump, coolant temp sensor... what could be wrong????

 

Ant, when you turn on your DEF or A/C, does the needle go down?

 

If I turn the heater on it goes down. Not my A/C though... actually its not even working, it ran out of freon. (small leak)

 

That indicates to me that the main fan (there are two) is not functioning. Check the relay or fuse that controls the fan. If they are ok, check the wires that leads to it.

 

^I just went outside to test the DEF mode, it looks like it spins both so I would check a relay or fuse.

 

The fans work... both of them turn on if I let it idle for a good 15 minutes or after a quick drive...

 

hmmm...I'm out of idea's then...

So what you're saying is that eventually it'll cool itself down without any help?

 

I'll double check with the a/c on but I have no freon. The fans are supposed to turn on though... I remember reading that somewhere else.

I had a friend tell me to take out the a/c condensor and clean it, it gets dirty and doesnt let air flow into the radiator.

 

Yes sir... it will only over heat
1. If its pushed hard
2. Goes around 3k or about 80mph on the highway for over 10 minutes
3. City driving, if I stop at a light and accelerate, it will raise the needle and overheat and after about 5 minutes it will cool itself if I drive it and dont stop.

 

hey I had the same problem! , did almost the same as you except I never changed my radiator. so I flushed the coolant, changed the thermostat,water pump and temperature sensor and my car was doing the same thing!! finally one day I replaced my radiator cap and since that day I have no more problems with my car over heating, so I recomend you to change your radiator cap, it is around $22 bucks at the dealership.

-Joser

 

Something is blocking the flow of coolant, or of air across the radiator core. If you take the cap off the radiator when the car is just beginning to warm up, and you observe the coolant level when you throttle the engine rpm up, it may go down a bit. If you don't see much movement in the coolant level, you may have something blocking the flow of coolant. Could be a chunk of gasket, a pinched or kinked hose, who knows. Gotta go looking for something out of place.

 

Check the radiator hoses, mine sprung a leak and the hole you couldnt even see it if you tried.. leave the car running and see if it starts shooting coolant out anywhere..

 

^This is a good suggestion

 

are you serious..you replaced your raidator cap and it was fine?...ANT if this works..tell me plz...this would be one very sad story...of how someone payed and changed all this stuff...then he changed his radiator cap and it fixed it

 

10char

 

Since you changed the thermostat, coolant temp sens then I would lean twords an air bubble in the lines or blockage of the lines, like stated above. The radiator cap is a possibility.

When the car gets to operting temp and the thermostat opens you should be able to see the coolant rushing through the radiator with the cap off. At least that will tell you coolant is flowing throught the radiator like it should.

 

okay where do I start lol...

I forgot to mention the cap was changed with the new radiator...

When I had done the flush and added water and coolant, I saw the delay from when its cold to when it heats up and the thermostat opened and the coolant really started flowing.

As for hoses, they feel pressurized. I dont have any leaks that I can tell but the hoses have never been changed ever since I've owned the car.

 

Did you take the car back to the shop that performed the radiator work or did you do it yourself? If the latter, I would suggest you talk to a reputable radiator shop if you haven't figured the problem out by the weekend.

 

I did all the work myself...

I'm thinking of air in the system but how do I go about getting the air out if that is the case?

 

drain the system and then fill it back up with new liquid...had the same problem with my brake lines..so maybe if you drain it and put in new liquid it will work for you overheating problem (and im not talking about draining the brakes, i just used that as an example of what you could do for your situation...lol)

 

it's the thermostat. check the big hose from the radiator to see if it's hard or soft when the car/temp is hot. if it is hard/ then it's ur thermostat for sure.

 

flush the whole system a few times, bleed the system, see if that helps.

 

So I guess I'll try to go out and flush/refill it this weekend. I"ll see what I can do, its really peeing me off.

 

I would check the thermostat once more before I went to all that bother.

 

hmmm dunno ant...my temp gauage is slowly going up...but i need a new radiator...and a water pump and a fuel pump...hope everything goes well!

 

I have flushed the coolant, changed the radiator, new thermostat, new water pump, coolant temp sensor... what could be wrong????[/QUOTE]

The only possible problems left (as you well know) Ant are #1 air bubbles/blockage, (which seems kinds unlikely to me) #2 A failure to one of your recently changes components (water pump blade? non oem nissan thermostat) #3 ......GULP...... headgasket

I had a old plymouth reliant that did a similar thing as your maxima. I wired the fans to a switch in my car and I would run them almost 100% of the time, I know its not reccomended but it can allow you some insurance while you pinpoint this problem

Also I wonder if your ECU issue is somehow related to your overheat? did this begin to happen shortly after they found you has the wrong year ECU in your MAX? It may or may not be related

Good Luck

 

I'd check the waterpump blade, or bubbles in the radiator.

 

Last night, coming home at about 3am I was doing about 80 on the highway and I look down and holy crap! The temp needle was at 3/4 of the way up! After a run on the highway and stopping at a light, it will go up as well. BUt once the car moves out of a light or traffic it goes down a bit. - Ant96GLE

Are you loosing coolant at all? I'm sure you've checked for leaks, but what about testing your exhaust? How does your oil look?

I had a similar problem with my 95 Lumina, eventually it turned out to be a tiny crack in one of my heads.

Good luck.

 

No need to flush if the coolant is already clean. Just rebleed. But it's starting to look like a worn out waterpump. Not fun from what I read for the VQ. I hope the bleeding works. Make sure the heator is on full hot when bleeding

 

Start the car with the radiator cap off, let it warm up to operating temp, any air bubbles should rise and go away. Then shut the car off and put the cap back on.

 

yea if u changed all those parts u def have air in ur system....a good investment is a burping funnel....it seals the system like a cap but has a pluger that will burp out air..really quite handy.......or just leave ur radiator cap off until all the air bubbles rise and shut-off replace cap and start......it could take up to 45 min for all bubbles to go away...u will also want to turn ur heat on all the way once the car reaches operating temp.

 

http://www.harborfreight.com/cpi/cta...emnumber=92008

kind of lik that but has a plunger to seal and then the air pressure from an air bubble is enough to "BURP" it i used on all the time at midas

 

i think its the head gasket also. hopfully its not but it sounds like it to me...

 

Exactly what makes you think it's a head gasket based on the information given so far????

 

I thought fourth gens has some sort of self air purge of the coolant system...mine got air locked once and I was able to work it out by squeezing the lower radiator hose until most of the air was out. Even though you have changed your t-stat, I would say that would be the first suspect, mine started acting like this before it finally bit the dust. Then after that I would say coolant blockage, or water pump.

 

Alright lets answer some questions here.....

1. I dont have any coolant leaks.. I just got in from work and checked it out.
2. Coolant level is okay in the small resevior... I have to go later when it cools down and check it inside the radiator.
3. If its the water pump.... No, its not fun... by any means. It was already changed once. It is a motha fawker. However, the water pump was done by a shop, and now the timing cover is leaking. I have a friend at another shop who said he would re seal my timing cover, so I may even ask him to do the water pump since its only $35 new.

So basically my problems are coming down to
1. Thermostat
2. Air
3. Water pump..... which I really hope is not the case...

I have to take care of this now.. before it gets hot. If not it will overheat all the time

 

Well rebleeding and a new thermostat is a cheap way of checking. You can even take the exisiting one and put it on some boiling water and verify the opening temp.

 

had a car over heat after replacing everything and it turned out to be the head gasket. i changed the gasket and no more over heating. thats the only reason i said that because he has changed everything.

 

^ Headgasket would also mean burning coolant right? Ant, do u notice any sort of smoke when driving?

Drive without the thermostat in and see if it still overheats.

 

ya now that i think about it it might of been messed up but im not sure cuase i had flushed it so many times.