ice cold ac but car temp is hot

[rspro]

ok guys i've been doing research on this for about a week now everynight. Here is my problem when I 'm using the ac the car temperature goes up and almost pass 3/4 of the gauge. But here is the tricky part it will only do it if I drive hard and speed excess of 50+mph for continuous periods. Here is what I have done replace thermostat, flush and burped the radiator. I'm tempted in purchasing a new radiator, but if that doesn't help I just blew $150+ and still having the same problem. And also if I turn the ac off or stop and idle for long period of time the temp will go down even it idles with ac on. I am really stumped here and help would be great.

 

[VtecvrsTurbo]

When you have the a/c on, check the condenser (next to the radiator) And see how hot it is. It should be warm, but not hot. Is the a/c fan coming on? Check the wires to your fans and make sure there not loose(causing the fans to turn on/off while driving) Flush your whole colaint system too.

 

[rspro]

When you have the a/c on, check the condenser (next to the radiator) And see how hot it is. It should be warm, but not hot. Is the a/c fan coming on? Check the wires to your fans and make sure there not loose(causing the fans to turn on/off while driving) Flush your whole colaint system too.

I have flushed and checked the fans, and they are good. So if the condenser is hot what does that mean? Does it need to be replaced is it clogged? And I have heard that if your refridgerent level is low that it could cause the overheating.

 

[rspro]

Can you run straight h2o during the hot summer months?

 

[ChicksDigBoost]

Check your radiator cap. You can run straight H20, but I would still run coolant just run a mixture with more water. Go to a place that free A/c checks and they'll be able to tell you if you have low refrigriant or have a clog.

 

[rspro]

Do you have to have coolant? Will it cause any problems with straight h2o? My radiator cap is new also.

 

[rspro]

Do you have to have coolant? Will it cause any problems with straight h2o? My radiator cap is new also.

 

[joe]

yes water boils at a lower temperature

 

[toybreaker]

Straight water has the best possible heat transfer characteristics.

Running straight water without a corrosion inhibiter is an invatation to serious corrosion issues on an iron block/aluminum head motor...

Distilled water mixed with redline waterwetter is the best combination for pure heat rejection. Waterwetter has corossion inhibiters and a lubricant for the water pump, and mixed with distilled water does the trick for a lot of people in Phoenix, for example.

I always run a coolant mix myself, as the anti-freeze will provide lubricity for the water pump seal. And the coolant mix will boil at a higher temp than plain water.

If you're only overheating with the a/c on, and driving hard, your cooling system is probably marginally ok. You might be able to address some small things to gain enough reserve to be managable.

The radiator is simply a water to air heat exchanger. If we can get more air thru the core, we'll get more heat removed.

So, a few quick/easy/cheap things to do/check are.....

Is the duct from the bumper to the radiator support installed and sealing up ok?

If you shine a flashlight thru the cores from behind, can you see debris/obstructions? The next time the radiators out, please backflush the a/c condensor with the garden hose to remove any cat hair, pebbles and etc.. that always collects in the condensor core. Do the radiator, too. Just pretend you are painting the core from behind with the garden hose. Go up one row and down the next with a sprayer nozzle held perpendicular to the core about 6" high, and you'll be suprised at what comes out.

The bottom couple of rows of condensor fins gets a lot of road debris thrown at it, and the fins are usually somewhat spranglified. A small screwdriver and some patience will get things straigtened out. Just start where it's not too bad, and insert the flat tip of the screwdriver in ~1/4" and lift the damaged fin back to straight. You'll get pretty good at it pretty quickly, but it'll take a couple of beers worth of time to make it all good...Try to not tear the fins off the tubes. If one tears, do a little surgery with dykes/side cutters. Where the fins are really bad, it sometimes helps to use two screwdrivers to kind of pinch the fin straight. Just try and align them with the row behind.

Did you use an o.e. thermostat?

What temp rating?

If you feel the need, the 300zx twin turbo radiator cap is rated at 16 psi. Just make sure the hoses are up to snuff, or you'll just be popping them right and left. I'm still on the fence about this mod myself. I think the potential for trouble with hoses/heater cores etc. outweighs the benefits for most people....but it may help in certain cases where the system is pushing coolant into the overflow tank.


Also, the a/c clutch really hates to engage/disengage at high engine speeds, so keep that in mind when you're turning a lot of rpm's...it'll really work the system uneccessarily, and could damage the compressor clutch over time.

Try a few things, and let us know if you're headed in the right direction. I think a lot of people are having cooling system issues right about now, so finding, fixing, and posting your results could help a lot of people.

Good luck!!!

 

[rspro]

Hey guys here is the update.... I drained some of the coolant (90%) and top it off with some h2o. I did this last Friday and so far it's doing fine. Especially today being one of the hotter days this week. So this is what I'm thinking since water dissapates heat better it's letting the radiator do its job. Could my radiator not be cooling efficiently enough to run with 50/50 mix? But so far it's working with the h2o.

 

[joe]

I would still consider getting your ac checked

 

[rspro]

Well tommorow morning I' m going to drain it again, but this time I'm going to try a 75% h2o mix. Joe, you stated I should still check the ac system, but why when it's ice cold?

 

[joe]

1..ok first thing i forgot to ask is what outside temperatures are you driving in? 85 and below and overheating would indicate a more serious problem maybe a/c or coolant system if your driving in say 105 and overheating with a/c on it would be alot more understanding that you are having problems.
2. More than likely you can get your a/c checked for free.
3. Low freon doesnt always = warmer A/C temps
4. I was also wondering if this problem just started happening or if maybe it started happening after aftermarket bumper was installed.

 

[Littlebeeper]

plain and simple, radiator. if you can get it to work with a higher proportion of water, great. If it still doesn't work then its the radiator, assuming you have tried the other ideas listed. You can take it out and have a radiator shop rod it out. costs like 50-75 where i live. they repaint the thing and everything. Mine would do the same thing. In town i had no problems at all but when i hit the highway, 10-20 minutes later the car would overheat. turned out less that 50% of the radiator was flowing and i had a tiny leak that i couldn't see, nor would it leak coolant on the floor. after that i could run all over with no overheating problems....till the damn upper plastic tank started leaking 1 year later . at least i knew the core was still good. bought a new one on E-Bay for $75 and looks OE and works great. Hope you get the car cool again.