It never did this last summer. It climbs way up and if I turn off the AC it goes back to close to normal. Whats going on here?

 

Well, you have a cooling problem. It could be several things. Coolant level, coolant mix, thermostat problem....

Use your Haynes manual.

 

check your coolant level. if it is full, your problem is your thermastat. those things have a tendency to go bad... and if you live in the SE like i do, this heat will make it harder for your engine to cool. i haven't done the repair on my Max yet, but it was a simple and cheap repair on my Supra and Jeep.

 

Is there a way to tell a thermostat is bad? I'm sure its never been replaced.

 

well, change it... see if your problem goes away.. i think its only like $15 for a new one. or i've heard that you can take out the thermo... heat up some h20 on the stove... put the thermo in it... and if it opens up all the way... it works... if it stays closed(cold position) its time for a new one.

 

I would disagree.. IF you have no problem when the A/C is off then I doubt your thermostat is causing it.. You need to make sure both fans are running when the car is on and hot.. As well I would take some engine cleaner and clean the radiator and the condensor..

 

Sounds as if you have a cooling capacity problem. You have a 1997 Max, have you ever flushed the radiator? If not I would plan on doing it. If it were my car and the cooling system had not been flushed, I would first flush it with the thermostat out. Replace the thermostat with a new one (preventive maintenance), add a 50% mix of a good non Silicate Antifreeze (Peak Extended Life Antifreeze is my 1st choice and it is available at Pep Boys), put in 6 ounces of Redline Water Wetter and fill radiator slowly. Put on radiator cap, I took my overflow tank off and thoroughly flushed it, then I filled it up to the Maximum Line on the over flow tank with a 50% mix. once you start the car and get it up to operational temp the air in the engine will be forced out so the extra coolant in the overflow will be pulled in when the engine cools. I would check the overtank level once the engine had cooled and fill it back to Maximum line. The next time you check the tank level it should be between Maximum and Minimum on the level indicators. That is where I keep my level.
You can get Redline WW from www.myoilshop.com use this discount code to get 10% off 675421 and they ship super fast. After doing all this you should be set for another 5 or so years. Hope this helps.
Be well!!!!

 

Thermostats are USUALLY not the cause of overheating. Thermostats are positioned in the flow so that they open outwards. When thermostats get weak, they make your engine run cold because it opens to early. The spring gets weak over time and the water flow pushes the t'stat open quicker.

Keep in mind I said USUALLY, there are cars out there with t'stats installed the wrong way - hance when they get weak, the spring can't open against water flow and you overheat.

I totally agree with Karguy with his suggestions. Have your system serviced by Nissan if you don't want to bother with collecting and recycling all the used fluids. I just had Nissa do my cooling system. It was 44 bucks. How can you beat that?? Took them just about 1 hour to do the job. Complete flush, refill and system test. Such a deal!!!!

 

Thanks, guys. It's most likely not the cooling system though because I've had the flush done probably 25k ago. It's only getting hot when the A/C is on. Otherwise, it runs normal.

 

Not sure how to answer this post. Hmmm...you say your water temp is "going thru the roof." Assuming the guage is correct, then your engine is running hotter than normal. If that is the case, you have a cooling system problem.

The advice given by the posts here is very useful. First make use the cooling fans are turning on when you switch on the AC. Then try a coolant flush and change the thermostat. Also have the radiator pressure tested. If those check out, then inspect the water pump for leakage.

 

If that is the case I would check that both fans run when the AC is on!

 

yes there is.

The way I do it is make sure when you pull it out to look at it to see if its open or closed.

Then you get a POT of BOILING water and put the thermostat in the boiling water and see if it moves close or open. if it stays the same,,, its locked and is no good. Go get one from your local auto part shop.. they should not cost more then 10 bucks

good luck!

 

your engine is a heat block

 

Its 90 bucks at my dealer, and thats with a coupon! You've got it too good njmax. I'm envious.

 

What he said!

 

How is this done? I know there isn't a dipstick right? Please advise.

 

If the thermostat is stuck closed you can not feel coolant moving thru the upper radiator hose when the engine is running and the engine is cold. You can grab the hose to see what I mean. Once the engine gets to operating temperature the thermostat opens and you can feel the vibration of the coolant passing through the hose.

If you have doubts, try this on another car without an overheating problem and you will see what I mean.

 

There is a radiator overflow tank on the front of the right side (passenger side) fenderwell. When the motor has fully warmed up the antifreeze should be at the full mark, when the engine is cold it should be down towards the minimum mark but not below it. That is all there is to it. If the level is too low add a 50% mix of antifreeze and water to the overtank until it is at the right level.
Be well!!!!