Need help from a car tech ...... Car temp goes up when air is run.... ('93 Nissan 240sx) ***UPDATE***

[CorCentral]

This just started happening yesterday btw .

Was running the air conditioning for a bit & noticed (while sitting at a light) that the car temp gauge was rising slowly & the air coming out got warm . Turned the air off , & it would slowly go back down to normal . The air coming out is cold when run but after awhile , the above occurs if I'm a light & sit for too long .

Checked the radiator (it was close to full) , added about 1 QT of water , checked belts & fans & noticed nothing out of the ordinary . No wierd noises , & all sounds the same as it did before this started happening . Had the radiator flushed two years ago also .

Anyone have any ideas ?

 

[flot]

Er... welcome to "how air conditioning works" ... the heat goes somewhere, you know?

It sounds like the rest of your cooling system is just experiencing gradual failure... you might want to check on your fan clutch and/or electric fans if your car has them.

 

[ElFenix]

if you're sitting at a light the heat exchanger and intake for your AC aren't getting any fresh air

 

[Heisenberg]

Have the A/C system checked. Especially the condensor and evaporator.

 

[notfred]

That's normal.

 

[CorCentral]

Checked the fans & both work properly. The one turns on when AC is engaged , etc .
This is the first time this has ever happened .


So I'll just take it in & have it checked out I suppose .

 

[flot]

Are we talking about a drastic and fast movement of the engine temperature, or very slow temperature creeping up?

Your engine temp WILL increase when you are sitting still with the A/C on. That's just a fact of thermodynamics. Now, if it is increasing more than it should, it is not the fault of the A/C - it is the engine cooling system not working as well as it should. I'd still lean towards one or both of the fans being at fault. If the electric fan(s) are working, is there an engine driven fan? It could be that your fan clutch is slipping too much. The fan clutch is a viscous coupling, that allows for slippage at high speeds/low temps but should make the fan turn faster when temps are high and the engine is idling.

If the air coming out of your A/C vents "got warmer" vs "got warm" there are two things at work there 1) the system cannot work as efficiently, because your radiator is getting too hot and that heat is seeping fowards towards the A/C condsenor (see comments about fans not working properly) and/or 2) a lot of cars will try to "preserve" themselves and they will shut off the a/c compressor in an overheat situation.

 

[CorCentral]

FLOT ---- The engine Temp has never before gone up while sitting still . It always stayed below mid point when AC was on in ALL situations & it just started doing this yesterday . Temerature goes up slowly but very noticable .

There are two fans , the main & the one more towards the front of the car that works when the AC is switched on . I understand about a car preserving itself in an overheat situation but the car has never done this before but it seems as though this is what it's doing now . I checked again & both fans seem to be rotating at a fairly high speed when AC is on but the fan clutch will be the first thing I have them look at when I take it in .

I'm leaning more towards what you said about the Engine/System cooling . Either something to do with the fan &/or a coolant flow problem .

I just don't want to be charged an arm & a leg to have them replace parts that are'nt bad .................

 

[CorCentral]

Update : Well I went to GoodYear to check on what it would cost to replace the fan clutch & they wanted $180. installed !!#@*#*!!
Screw that ! ............. Called Autozone & they had one in stock & it was $40.00 .
I installed the fan clutch . It took me about 30-40 min.

I still notice that when running the AC the temp goes up slowly & then after awhile (while driving 55mph , not stopped) the AC gets warm . When I turn the AC off , the temp goes down slowly . It does seem that the temp doesn't rise as high as it did before new clutch but still goes up enough for the AC to get warm .
I was told by another tech that it could be the Thermostat & I should replace it anyway to narrow down problem without spending tons of cash .


Ideas ?

 

[LordMorpheus]

my car does it. GOt stuck cause the cops closed the highway last night, some train lit on fire, and the car next to the burning one was full of all sorts of HazMats . . . so I sat . . or my car sat and I walked around for about an hour. When we started moving (averageing 0.000000001 mph) i had my AC going and my motor got purty hot . . till I turned the AC off.

 

[elanarchist]

Somewhat related to this, my car's A/C system seems possessed or something. Even when I turn it completly off, when I accelerate hot air comes out of the two side vents and warm air comes out of the two middle vents. When its on, the hot air still comes out of the two side vents and somewhat cold air comes from the mid vents. Anyone have this type of problem before?

 

[blahblah99]

Hmmm.... did you check if the auxilary A/C fan comes on when you turn on the AC? Or if the air in the cooling system is bled out? The coolant bleeder valve is in the front of the engine, on intake manifold. Make sure all the air is out of the system, and that the A/C fan is ON when you have the AC on.


Edit: nevermind, just read through your posts and it looks like you've checked the fans... I guess other cheap alternatives would be to bleed the air out, change thermostat, check your water pump belt (which also drives the alternator) to make sure it's snug.

 

[Ladies Man]

I had to get a new radiator...

93 mustang... would get really hot with ac on.... now with new radiator all is well.... Cost me $130 at napa... modine radiator with a lifetime warrantee.

 

[thedarkwolf]

Originally posted by: Ladies Man
I had to get a new radiator...

93 mustang... would get really hot with ac on.... now with new radiator all is well.... Cost me $130 at napa... modine radiator with a lifetime warrantee.

Just got the a/c working again on my 89 5.0l mustang and its doing the samething. Apparently the radiator was barely adequate when new and now its just not cutting it. Mine isn't that bad yet but I'll probably replace mine with one of those fancy aluminum Summit radiators whenever I get around to it.

 

[Thegonagle]

Your car is old enough to need a new radiator.

"Gradual failure of the cooling system" usually means you need a new radiator. It gets clogged with sediment over time, which does two things: the sediment gradually closes off the narrow coolant passages through the cooling fins, reducing the volume of flow. The build-up of sediment also insulates the cooling fins from the hot water to a certain extent.

If something else in the cooling system fails, you would generally experience "sudden failure of the cooling system."

 

[CorCentral]

May I remind you all again , this happened all of a sudden . It's not the radiator .
(changing thermostat today)

Any techs out there ?

 

[chin311]

you could try the theromostat, but last i knew, it shouldnt be that if it only does it w/ the A/C on...usually if its the thermostat it will do it ALL the time...

hmmm, its been TWO years since you flushed/changed the fluid?? geez, i do it yearly at least...try that too, only cost about 5 bucks and an hour