My 2000 is overheating whenever the AC is on and the car isnt moving very fast. turn the AC off and no overheating. Keep the car moving and no overheating either. Coolant level is good, coolant is pretty new. I changed out the thermostat and it hasnt made a difference. I noticed that only one of the two radiator fans is coming on, at least only one was on when i checked, I dont know if they both come on all the time or not. What controls the second fan? The fan isnt blocked, Is there a fuse or switch to check? The fan i'm talking about is the one closest to the passenger side of the vehicle.
Thanks for any input you have.

 

I'm not sure when the second fan comes but I think it is supposed to come on when the AC is turned on even if it's parked. More than likely you need to replace that one fan motor, you can unplug the connector and test it straight from the battery with some wires.

 

Do this because i had a problem very similar to this, and i had to replace my motors, if you have a haynes repair manual it tells you how to check the fan motor. It might be the relay also.

 

very simple tshooting procedure.. eliminates all guesswork.

Drive the car locally under those conditions until you see the temp gauge start to rise. Pull over, and leave the car idling (which will actually increase the temp), you should be able to see if both fans are going.

Guessing sux!!

 

I just checked with the engine at temp, ac running, the passenger side fan is not spinning. So where is this relay to check?

 

Unplug the fan and use a volt-meter to see if you have 12-14 volts going to the fan. If you do, then you have a bad motor. If you don't, then you have a bad relay. I'll bet it's the motor.

 

I'll do that, where is the relay, so i can check that as well?

 

I am having the same problem with my car. It only happens more/less when the AC is on. I notice the gauge jump up when i come to a stop. The thing is that both my fans work, i checked. I thinking it might be the sensor or maybe the water pump. Does anyone know if the stock water pump comes with a plastic impeller or metal. I was thinking maybe something happend to the impeller, like it cracked or broke. If it is plastic there wouldn't be a noise like if it were medal. But who knows....I brought my car to nissan yesterday and they said today that they need to keep it for another day to diagnose..By the way this happend to me last summer too and replaced the thermastat and that didn't work....The guy at Nissan said it was normal for cars to run that hot....Ya..right!!!!!!!!

Ya this is normal operating temp's for a maxima....Ya.. find another job buddy!!!

 

Well i cant say what your problem is for sure, but i'm betting one of two things.

1. The fans only operate at slow speed (maxima fans have two speeds, controlled by relay)
2. bad water circulation. Which could be from water pump, clogged radiator, or other reasons.

Ha ha, nope that's danger area on the temp guage for sure, in my opinion, any time the guage gets above half you have a problem. When mine gets up there the AC kicks off and i start to bake. Silly techs, that's a totally unacceptable range.


As for me I dug in and hot tested both fans directly to the battery, the driver one difinately works, and the passenger one definately does not. so now i have to figure out where to find a motor. Any ideas? cost?

 

I would def recommend going with a nissan part. The aftermarket ones from autozone and the like don't fit well in my experience and seem cheap. You can go to http://www.courtesyparts.com or call Dave B (512-444-1400 ask for Dave Brunette in parts) he is a good guy to deal with and will give you the lowest price he can get, definately mention the org.

 

could also be a clogged radiator. my 00 was overheating and the dealership checked everything. ended up being the radiator. got one new online for about $120.
leason learned - flush radiator once a year to prevent clogging.

 

replace the fan motor.... the sensor to go bad... hummm... maybe but there is a bigger chance that the motor is bad....as for Sooner comment... do a radiator flush after replacing the motor.......

 

Well...Nissan replaced my temp switch thinking that was the problem, but it didn't work. On the way home from Nissan I noticed the temp shoot up so I had my friend hook up his Snap-On Modus scanner to my car and it said my ECT was 261 fahrenheit, which is pretty damn hot...Fans both work, thermastat was replaced...what the heck else could it be...i mentioned the water pump to the service writer and he said he couldn't check it because it was encased in the engine...He was kind of a pain in the *** about it. But I assured him that I could give a S*** about if the engine blows because for one, i have it documented that the car was brought in twice for the high engine temp and two, the car has an extended warranty, so nothing would come out of my pocket if it blew. I just wish they could figure out wtf is wrong with it....

 

the only thing left to check is the radiator

 

Is there a way of testing the radiator to see if its bad...or do u just replace it?

 

check the hoses coming to and leaving the radiator. "in" should be firm and hot (so to speak) and the "out" firm and cooler.

 

I cant believe the replaced the temp switch, maybe if the fans werent coming on at all! I hope you didnt have to pay for that. Are there a lot of insects in your area? My uncle lives in a rural area and has to spray out his radiator fins from bug guts every year or he overheats.

 

Can a faulty rad. cap cause overheating? Did u ck/replace that? Just a thought...

 

Yes, if the cap has too high a pressure, the system can overheat. However, the function of the cap itself is to "release" when a certain pressure is met to prevent overheating.

 

My 2k1 with 58k on it is overheating, had the t-stat, lower and upper hose, and belts replaced. It's still overheating. Their is no leakage from what I can tell and the fans are working. What should I do next? How can you tell if it's the water pump or radiator. Also, should I replace the radiator cap first?

 

 

Keep it up and you will be in no time

 

My 02 overheats if I drive up a long uphill, especially with the AC on. It will overheat with the AC off also if I drive it hard enough, but is more prone to run hot with the AC on. Any reccomendations? Had the thermostat replaced, and a water outlet gasket. The dealer I took it to said there was an air bubble in the cooling system, so they flushed my cooling system. This fixed it for a short while, but I was driving really hard up a steep hill one day because I was in a hurry and it started doing it again. I was furious. Anyway, I'm not the type to drive my car hard very often, but if I'm running really late, and I'm in a hurry, of course I'm going to. Any reccomendations? I was thinking it had to be either the radiator or water pump. Fans are kicking on.

 

No rablack, I'm still working on it. I was on vacation throughout July, so I put off the repair. I suspect it's the water pump, but I'm too novice a mechanic to try replacing it myself. I'm trying to figure out what shop to take it to. My last experience with the Nissan dealership was not good, so I'll probably use a local place.

 

My vote is on the radiator....Just had mine replaced for overheating...they replaced everything before that except for the WP.

 

you can tell if your water pump is working or not by checking the radiator hose. if you feel liquid running through the hose at operating temp, the waterpump is working. try spraying the radiator with a hose and blast out all the garbage blocking the fins. i did that to my condenser and radiator and ac ran colder and car idle temperature went down back to normal

 

I had the same problem with uphill accleration under load, the temperature gauge started to move up, this was when we in CA had 110 degrees and when one drives under these temps, all bets are off..

Anyway, I immediately flushed my radiator and it really helped me to bring the temp lower under uphill and under load. My suggestion would be flush the cooling system, pl. note every time you flush it would have air in the closed system. Do bleed the air from the air relief valve, it is right next to the air filter housing.

Good luck!!!

 

??
if its unplugged, shouldn't you have ZERO volts?
unless something is shorted, or acting as a capacitor somehow, like cooling systems can do if you are that lucky


to all the guys that say its hotter with A/C ON, IT IS PERFECTLY NORMAL!!
that's because the condenser is in front of the radiator.. so a/c refrigerant gets cooled first, and all that hot air is used to cool the coolant in the radiator
no need to state it in every other post anymore

very true, but it does not measure current. if you have a partially clogged radiator this won't help
If you want to measure it, it'd take quite a bit of work, but take the whole radiator out, stick a water hose in it and wrap it up with a towel, and then let it run out the other end of the radiator hose. it should definitely be slower that the rate of the water hose because it's a thicker hose, but estimate amount of flow
or fill up a bucket with water hose only and count how long it took, and do it from the radiator to compare

 

No.

Open circuit (i.e. unplugged) = max voltage, zero current
Short circuit = low/zero volts, very high current

 

Car overheating while traveling fast on highway with fans working - clogged radiator or possibly water pump, but unlikely. Car overheating in traffic, with ac on - most likely fans are not engaging. Also check if you have enough coolant.

 

Turned out to be the radiator. Guess I got a new t-stat for the next 60k miles out of the deal also. So far the water pump is unfazed. Also, the mechanic suggested doing a chemical flush, but thought there was a 50/50 chance that would fix the problem. They charged me $265 for the new radiator and 2.5 hours of labor. I thought that was reasonable for professional repair. The dealership wanted about 40% more than that to do the work. Glad I didn't go there!

 

Well, I had it at the stealership for my small oil leak (which turned out to be a valve cover gasket that's covered under my warranty luckily). They didn't want to cover my clogged radiator though, because it wasn't a crack or hole, ect. I laughed when they wanted $500 to install the radiator, so I bought some Prestone Super Radiator Cleaner and I'm going to try that. Hopefully it gets rid of my blockage. My main question is, on the 02 Max, where is this "air relief valve" to bleed the system located? I looked in my Chilton's, but it has a pic for a 93-94 Max.

 

cooling fan motor.. join the club.

o

ps. i am selling 1 working motor

 

While you have the fans out, take the radiator out too. Clean the condensor. Sometimes air doesnt flow through and there's a good chance you have crap between the condensor and radiator that restricts air flow.

 

My maxima is again overheating on highways and uphill when speeds are greater than 70MPH. I replaced the upper and lower radiator hoses but then it hasn't helped. The fans work and the radiator was flushed recently and I am pretty certain the radiator is not clogged.

Any ideas what could be going wrong? Do I have to replace the thermostat , will that help.

 

haha im an idiot.. dunno what i was thinking that day.. u said going into the fan = the plug for power of course!

 

why are you certain the radiator is not clogged? Mine became clogged after I flushed it, because it dislodged all the rust and crap inside.

 

Thats messed up...I had a clogged radiator and the dealership near me covered it....i guess its up to each dealership whether or not they want to warranty something....

 

Everytime I flush (2yr/24Kmiles which ever comes first), it is clean, no particles. Only the overflow tank has some sediments. I bought the thermostat and gasket and will replace it over the weekend.