I'm having some serious overheating issues that are really starting to get to me. When the temperature is over 75 or its humid, my car starts to overheat. It only happens when I drive over 3000 RPM for a continual period of time, like on the highway, and especially when the car is under minimal stress like going up a small incline. When going up, the temperature needle slowly starts to climb and if I have some music playing the needle will jump everytime I hit some bass, something it normally doesnt do. Once I put the heater on full blast, it slowly goes back to normal temperature.

As far as troubleshooting, I've done the following: I just got a new water pump a few months ago and its flowing just fine. I also drained the coolant and filled it up with a 50/50 mix, as well as replaced the radiator cap. And I also changed the thermostat. Now I'm totally stumped because it continues with this problem. The hoses have pressure when they are hot and I'm not blowing any white smoke.

I'm totally stumped... I'm going to go buy a new radiator as thats the only thing I havent done yet. Has anyone had this problem or anyone know a solution that I havent tried yet?

 

i did some research, i feel your pain, my old honda was plagued with these problems, is air properly getting to the radiator? becuse at highway speeds it should theoretically be cooler, but maybe you dont have a plastic guard on the bottom or osmething, and its bypassing the radiator? just a theory

 

There is one thing you didn't change, the radiator. Maybe there is a lot of corrosion inside hindering the flow of fliud which will also make the car overheat. Once you change the radiator, you'll have a mostly new cooling system. Your heater core is the last part.

 

If it is the radiator don't waste a boatload on a Nissan unit. I just picked up a new one from Koyo for $127. I walked into a local radiator repair shop and they had it there in 20 minutes. I dropped out my old one and there was a bunch of dirt and hair on it. So to save money you could pull it out and make sure there is no **** over the front. I was in an accident last year and I got a new radiator. So after one year and 11K I accumulated about 20% blockage. So if yours is original it could be filthy.

The nasty old one...


Here is the new unit. Install was a breeze. More details on page 8 of my homepage if that is the problem. BTW, no, thats not me.

 

yeah, dam i thought i read that he changed that as well, goto a shop and get it boiled out might be a cheaper alternative to replacing it, when i had the honda, it was costing $250 from a local shop, i purchased mienf rom 1888 radiators or somethign, got it for $100 2nd day air shipped for free, you might not need to change it, there may be tons of deposits inside that are restricting flow

 

Or the other obvious is a head gasket leaking. Autozone sells little kits to check if there is exhaust gasses in the coolant. Exhaust gasses leaking into coolant is typical of overheating at highway speeds.

There won't necessarily be white smoke pluming from your exhaust, or coolant in oil, if your head gasket is leaking.

 

For the summer put in a 70/30 water to coolant in the rad. You might also have air pockets in the system somewhere.

 

THanks everyone for your replies... I'm gonna go with a new radiator... thats whats great about having worked at an auto parts store... I'll let you guys know what the outcome is. But like deezo and broaner said... most likely its all clogged up, I've accumulated about 40,000 miles in the past year and a half..


This is very interesting, I was wondering that but I didnt think so since I wasnt burning any coolant... I'll see what I can do with that.

 

One more thing you might want to do before you replace or repair your radiator is make sure there isn't an air pocket in the coolant system. Air in the system will cause the tempature to raise & drop, raise & drop. Just open the cap (when it's cool, not hot) start the car & let it run for alittle while. Any air trapt in the system will be able to bleed out. If there is a significant amount of air in the system you will be able to tell because the liquid in the radiator will be lower. Then all you have to do is top it off, put the cap back on, let the system pressurize & check you gauge to see if it is still getting hot. If the problem continues, then replace the radiator.

 

You should also check the operation of the electric cooling fans. If you turn the A/C on, both cooling fans should turn on. With the A/C off, the fans will turn on when the engine reaches operating temperature.

If they don't turn on, it could be a sensor problem, wiring problem, or fan issue

 

on what nostrixoxide about bleeding any air out of the system... I know I read another old thread sometime ago about someone with similar symptoms - and they ended up finding out that the radiator was clogged, so the coolant was just not flowing through the system... by doing the test that nostrixoxide suggested, when your thermostat opens, you should notice the collant in the radaitor bubbling/turbulent... as opposed to just still/not moving when the car is initially started and cool.... also make sure the fans are kicking in - as d_hammer suggested.

 

1) check the fans
2) air bubbles
3) inspect the thermostat by putting it in boiling water and verify it's operation

I have a very hard time believing that your radiator is bad. If it's clogged with debris then remove it and spray it out and get a fin repair tool.


Dave

 

Anything can happen inside of a radiator over time and corrosion is the number one cause of radiator failure.

I went through all of this with my Toyota Pup.

 

As d_hammmer said, check the operation of your cooling fans as well, esp. when your a/c is on, if you don't hear the fans engage but the compressor kicking in, then the fans have kicked the bucket, if the fans are fine but you're still having overheat issues, then bye-bye radiator

this is also a good time to check your hoses for wear

 

[QUOTE=Ant96GLE]. if I have some music playing the needle will jump everytime I hit some bass, something it normally doesnt do.

Have you checked the gauge? Vibrations should not make it "jump"

 

Are you sure it's overheating? Have you measured the temperatures? Maybe your gauge cluster doesn't work. Or CTS (Coolant Temperature Sensor).

 

When I replaced the coolant with the new thermostat I made sure to try to bleed as much air out the system as I could. I ended up bleeding it twice when someone on the board here told me to try it.

My fans are working perfectly. When I turn the a/c on the fans come on as well as when I let it idle for a while and it gets warm.

Whats funny is I just bought a new cluster from a local org member to install. I know its funny but since my tachometer isnt working normally, I'm going to install the new cluster tomorrow and see what happens. I'm going on just a hunch.

As for the fan, the fins are open and it doesnt have bent or clogged up fins.

 

What about the temperature sensor itself? I know that it is located right on the engine coolant port on the engine near the upper radiator hose. Could this be causing you to "think" that your system is wacked up, but it really isn't?

 

See, this is an instance in which an OBD-II reader would help eliminate having to guess around. Yet another reader to invest in a diagnostic tool. Its a mod even though it doesn't make you look better, go faster, or turn quicker. You might be able to borrow one from a local store and see what your temps are reading.

 

Your right... thats probably the ONLY reason why I miss my 22 year old Toyota Corolla, if anythings wrong, you know right then and there....

I bought a new radiator, I'll be installing it tomorrow sometime and keep everyone posted. This week the temperature is going to be at around 90... the way it is now, it'll be overheating in no time...

 

Yeah, but I'm using an Auterra and it was 189 again today.




Actually here is an instance that I was running 196. In a parking lot it will sometimes rise to 200+. WTF? You guys think I should run a wire to the thermostat when I do my grounding kit? If so, I need to know where it is. I guess I could figure it out. I just haven't looked very hard yet.

 

how do you bleed the system?

 

Definitely could be the radiator, but worth looking at the fans too, as they'd be cheaper. I'm having an overheating problem too, but not quite like yours. There are three separate relays that run the cooling fans and if any one of them is sticking/bad, you could have trouble (although it is more prevalant at idle/stop). The fans have three settings, depending on coolant temp, vehicle speed, and whether or not the A/C is on. They can either be off, low speed or high speed. A relay failure could keep them from coming on during certain conditions.

 

stop driving around those fat huchies

 

Your girls not that fat ... by the way tell her she makes slamming burgers..


The fans work fine, they turn on when they're supposed to. I've pretty much narrowed it down to two things, the radiator which I picked up today and am installing tomorrow and the coolant sensor... we shall see... it sucks driving around in 80 degree weather with the heater on full blast and the windows wide open to keep the temparature level.

 

ant does the car actually overheat or does the needle just rise. cause i remember you showing me the needle bounce when you turned up the music. maybe it could be a bad meter or something.

 

yea it still does the bouncey thing. I actually replaced the entire guage cluster on Saturday because my tachometer wasnt working right... as I was driving around today.. it started overheating again. I actually do think its overheating because the needle slowly goes up and when I put the heater on it goes back down. I'm hoping that its the radiator thats getting clogged... kinda like when you have cholesterol... and the reason its overheating is that at high rpms the clogged lines dont let as much water pass through as they should... which would make sense as to why it doesnt overheat when its idle... unless the a/c is on. I'm going to install the radiator tomorrow and take it out for a ride at night. By the way check your PM's.

To the guy who asked how do you bleed the system: You start the car with the radiator cap off.. when its cold obviously and let it run and add fluid until it fills up and bubbles stop coming out.

 

my needle jumps up & down when i start the car but mine don't overheat someone told me is a bad temp sensor

 

I hope thats whats wrong in your case, thats a breeze to change. I have to take mine out.. supposedly theres like 3 different kinds, you have to read off the part # to see which one you have.

Mine jumps when its starting to overheat and I have my system on, when the bass hits hard, the needle starts jumping... even with the new guage cluster... my car has issues.