Jibberish18

Hello Everyone. My apologies if this was asked before. I did some searching but couldn't really come upon a definitive answer.

To give you a brief history, the radiator, thermostat and radiator cap are all very new (Radiator was rotting into dust literally). Even added a bottle of water wetter. The car has no problems keeping cool (gauge is always in the correct area) and warms up quick enough. My problem is this, when the car finally warms up to the point that the fan needs to kick on to cool off the coolant, the fans kick in to high gear like they would with the air conditioning on. Problem is the air conditioning is not on. Once the fan is on I wait and wait for it to turn back off but it does not.

The fan is sucking up so much energy from the alternator that turning on my fog lights for example dims all the lights on the car. I can slightly hit the gas in Park and watch my lights bright up as the RPM's go up. I'm not sure what is causing this. I half suspected the coolant temperature sensor but I'm getting no OBDII codes. Although it is easy enough to change and cheap. The other possibility was a possible water pump going bad but this doesn't sound likely as the cars ability to stay cool seems just fine, even in hotter weather.

Thanks for looking.

00Lightsout

if its showing the right temp on your gauge, then I doubt it's the coolant temp sensor that is newer. what is the lb's on your radiator cap? it could be your FAN2 relay by the battery, or your new thermostat may stay too far open...btw there are 2 thermostats.

Jibberish18

The cap pressure is 13 psi. 2 Thermostats you say? Where would this 2nd thermostat be? The thermostat only opens a maximum amount doesn't it? I'd understand if it stayed stuck open but then it would take a while for my car to heat up no? Especially in cold weather, which is not the case.

00Lightsout

u said it "warms up quick enough"... too quick?

the second therm is between the OEM intake and the 'front' head... it's a small pita to replace... but my best guess would be the connector to the temp sensor(directly behind the 2nd therm) simply needs to be cleaned and scuffed

is there any moisture around the alternator? Yet the problem seems electrical... I'm not sure if the ECU controls the fan, or if the temp sensor triggers the fan.

DennisMik

iTrader: (2)

If you have a 3.0 liter engine, you have 2 temperature gauges. One is for the gauge in the dash and the other is for the ECU to use. If the ECU temperature gauge is bad, sending out too high of a temperature reading, the radiator fans would be on and the temperature gauge would show normal because it is run by another sensor.

Get a quality OBD code reader (not one of those cheap azz $30 pieces of crapola) hooked up and it will tell you the temperature of the engine coolant as reported by the ECU temperature sensor. Best time to do this is with a cold engine that has not been started yet. That way the reading should be the outside air temperature.

There are more things to consider but without knowing what year/engine you have, I'm not going to get into them. All the year models of the Maxima have differences from each other, they are not identical.

Jibberish18

I have the 3.5L Engine. When ordering my thermostat from Rockauto I only saw one option. It takes about 2 or 3 blocks to warm up on a 50-60 degree day. Seems normal.

Driving it and paying attention these past few days, I realized that it takes a bit of time for the fans to kick on (normal) but once on they take quite a while to shut back off. They DO shut off but it just seems to take a while. Sometimes even when coming off of the highway it seemed like they were still on. I'm not absolutely positive of that. You know it could be acting normal but I haven't compared it to another Maxima to know and I just started driving the car on a regular basis a few months back (It was my wifes before).

To me, if the fans are drawing enough power to dim all the lights of my car then something isn't right.

dwapenyi

iTrader: (3)

Yes, and I would also look into the condition of the alternator and wire grounds. You mentioned rust before so perhaps your ground connections need cleaning. Also, unplugging and plugging in the alternator connections may dislodge rust, freeing up the alternator with a clean path to deliver electricity to the rest of the vehicle.

quick-e

is your defrost on by chance?

DennisMik

iTrader: (2)

Since you have the 3.5 engine, there is only one temperature sensor, not 2 like the 3.0. So if the dash gauge shows that you are not over heating, then you probably aren't.

In your 1st post, you said that the fans are running at high speed. How did you determine this? With the a/c turned off, the fans aren't supposed to run until the engine temp reaches 212º F (100º C). In regular city driving, the water temperature goes up and down between 180º and 200º F (82º and 95º C), which means the fans should not run at high speed.

What I think is that your thermostat is the problem. I think your thermostat is not opening up enough to allow full full water circulation. Maxima.org has many, many threads where people put non-Nissan thermostats in and the car did not cool properly.

But I still think you should get an OBD reader to see what the coolant temperature is running at.

Jibberish18

No sir.

Rockauto and other car part sites show two sensors. One for the reading of the gauge and the other for the fans.

I honestly think I will change the Temperature Sensor. It may be a waste of money BUT it is only $20 and it is very easy to change. Worst comes to worst I was suppose to change the transmission pan soon (Is rusting just like every other underbody component of this car) so while I'm there I could ask them to take a closer look. I'll report back once the temperature sensor has been changed.

My Ford Focus allowed me to see this info on my dashboard digital readout (reserved for Odometer Readings) once some trickery was applied. Does the Maxima have this?

NmexMAX

iTrader: (22)

IIR, this pic also holds true for the 02/3, this is from the 95 FSM.




Correct me if I'm wrong Dennis.

DennisMik

iTrader: (2)

Rock Auto has their listing screwed up then. There is only one water temperature sensor in the 3.5 engine. If you follow the upper radiator hose back to where it attaches to the engine, you will see a sensor with 2 wires mounted in the pipe after the hose ends. If you look at a 3.0 engine, you will see 2 sensors, a sensor with 1 wire for the dash gauge and right behind it the ECTS with 2 wires on it.


I still maintain that you should get an OBD reader and look at the temperature being reported by the sensor. Do it before you start the car while the engine is cold and again when you have driven the car for a while. Five minutes of your time will tell you what you need to do.

I've never heard of that capability in the Maxima, so I'll go with no.

DennisMik

iTrader: (2)

You are correct. It is the same.

I've never looked, but I bet it also applies to the 6th and 7th gens, too.

Jibberish18

Thank you for the information guys.

Jibberish18

Oh and I guess you guys were right about it having one temperature sensor.


http://parts.nissanusa.com/nissanpar...partcode=22630

I have to ask, how difficult is it to change the thermostat I thought it was a simple 3 bolts until I had my radiator, thermostat and hoses changed out. The mechanic said he had to take out the alternator for some reason.

NmexMAX

iTrader: (22)

You don't have to, just be intuitive.

DennisMik

iTrader: (2)

Would we lie to you? Of course not, not with the reputation of Maxima.org on the line.

As others have said, It can be done without removing the alternator.

Jibberish18

Well I've decided to buy a Bluetooth enabled OBDII scanner and connect it to my Android phone. This should give me a way of looking at any perimeters I'd like in real time, including coolant temperatures. Plus it's cool! I'll report back with findings.