I got my AC charged and now I am overheating. The AC works pretty well, but NOT ice cold. I previously had NO issues with the car overheating when I would turn the AC on. The AC previously would NOT cool the car but it wouldn't overheat either. Now the AC is working but the car overheats pretty quickly. Could the shop have overcharged my AC? I did briefly run the car with the AC off but I couldn't tell if the temps went down significantly because I was down the street from my house. I do not have a thermostat installed but not sure if that would cause an issue NOW that the AC is charged. It ran a cool 185* without the thermostat.

The car wasnt put on a lift for the AC work by chance was it? If so maybe a crushed coolant pipe. Try running th car with no AC to see if the temps stay normal. The AC being on does put a bigger load on the engine and makes it run hotter. I would also put the thermostat back in and see what happens.

stephen

Make sure you've got the correct ratio of antifreeze/water and it's fresh,
Burp your system,
Put the thermostat back in,
Check for collapsed hoses, crushed pipes, was the car on a lift?
Double check the level in your overflow tank.
Pressure wash out the radiator fins.
Replace your radiator cap in front and thermostat cap in rear.
Double check for any leaks.
You may need to chemicaly flush out your radiator.

I will say that I upgraded my water pump prior to having my AC serviced, My primary battery cables are new and so are my grounds, new alternator too so my electrical system can handle the extra power requirements of the air.

Does your radiator fan come on when you turn on the A/C? If not, that could be the problem.

The car was NOT on a lift and I had 185* temps right before I got the AC charged. Now it holds a steady 248* with the AC OFF. With the AC on and idling it was @ 249 and did NOT reach the RED zone. However, that may change as soon as I drive it again with the AC on. It is too much of a coincidence that I NEVER had any overheating issues but as soon and the AC starts working correctly, it starts overheating. Even with a bad thermostat it ran @ 220* and when I removed the thermostat it went down to 185*.

Could the engine temp be reading incorrect due to AC overcharging? Is the evap system tied in with the AC and the engine temps? It is just funny that I get my AC charged and my car starts to overheat.

[This message has been edited by nosrac (edited 08-26-2010).]

Check and see with the AC off that the compresser isn't running.

IF THE COMPRESSER ISN'T RUNNING - Then it doesn't make ANY difference what charge is in the AC. So the problem isn't directly from the charging but from something else.

quote Originally posted by Blacktree: Does your radiator fan come on when you turn on the A/C? If not, that could be the problem.

Fan come on just fine. Problem started after the charge. I am no mechanic but troubleshooting 101 says if something is working just fine and you make a change and then something breaks, most of the times it is the thing you changed that caused the issue, no matter how unrelated it seems.

I don't know what to tell you. With the compressor not running there is no additional load on the engine. What's more there is no additional heat load being dissipated right in front of the radiator. The only difference I can think of is that there is perhaps an additional pound of weight that the car has to take along with it.

There are only 2 things I can think of at the moment. Either the guys at the A/C shop accidentally messed up something in the cooling system while they were charging the A/C (kinked radiator hose? dislodged overflow tank hose? damaged overflow tank?), or the temperature gauge (or the sender) is off. You can use a scanner to compare the gauge reading to the ECM sensor reading.

Also, don't be too quick to assume that the A/C recharge is causing your cooling problems. While it's a good possibility, it may also just be a coincidence.

Found this on the net ! and it describes the issue I am seeing. I am going to take the car back and et them to charge at a lower PSI. What is the recommended PSI for our cars anyway? I could NOT find the lPSI level in the Hayned manual.

########################SNIP
Also, if you recently recharged your a/c (especially if you converted to R34 and didn't reduce the volume of refrigerant to 80% of factory recomended capacity) you may have the system overcharged, which will cause the engine to lope at idle, and believe it or not...overheat!


http://www.supramania.com/f...dex.php/t-54066.html
########################SNIP

[This message has been edited by nosrac (edited 08-26-2010).]

quote Originally posted by nosrac: Fan come on just fine. Problem started after the charge. I am no mechanic but troubleshooting 101 says if something is working just fine and you make a change and then something breaks, most of the times it is the thing you changed that caused the issue, no matter how unrelated it seems.

The a/c service people probably messed with cooling system, perhaps checking coolant levels or what not. If they don't understand a Fiero, it's very possible for them to do more damage than good. Do you own due dilligence, check the caps, burp it out, check the temp sensor, make sure the cooling system is holding pressure.

I bet that the service people messed up something on the cooling system while they were charging up your a/c if the overheating problem developed at that very moment. my $.02 cents for what it's worth.

Edit.... the a/c service people could have introduced a huge air pocket in the cooling system simply by incorrectly checking the radiator antifreeze fluid.

[This message has been edited by jetman (edited 08-27-2010).]

Found this on the Net too. Seems like the exact problem I have. Not sure how to fix it though. My was blowing outside temps after the First charge, and Now with the seconf scharge and suspected overcharge the air is cold but the car overheats I have the R134A conversion too.

http://www.acsource.net/acf...?f=1&t=8109&start=20

[This message has been edited by nosrac (edited 08-26-2010).]

I am hoping that you are not relying on the Fiero temperature gauge for your readings. I would verify these with a scanner or WinAdl before I did anything else.

quote Originally posted by josef644: I am hoping that you are not relying on the Fiero temperature gauge for your readings. I would verify these with a scanner or WinAdl before I did anything else.

I have a aeroforce scan guage.

To reinforce what phonedawgz said, if your car is overheating with the AC turned off then the AC cannot be the problem. You need to look elsewhere.

The fact that you were running without a thermostat and seeing temperatures over 200 F even before you had the AC charged tells me that the cooling system wasn't working right before and isn't working right now. My '88 (Formula) runs at a very consistent 200 F (+/- 5 degrees) with a 195 degree thermostat ... whether the AC is on or not. If your car overheats with the proper thermostat installed there is something wrong with the cooling system, not the AC. You need to find it and repair it. Fixating on the AC will not help.

[This message has been edited by Marvin McInnis (edited 08-27-2010).]

AC pressures should be close to Ambient Temperature (I am an EPA certified AC technician for automotives :P). So if it is around 80*F outside, the high, and low side pressures, should be 80PSI, Engine Off. When running, the pressure should be like 20-40PSI low, 140-200PSI high, it is variable.

Now onto what others are saying, if you are overheating while AC is off, then the compressor clutch is disengaged, and it is not overloading your engine, which means, you will not get an AC overheat condition.

The FIRST thing I would check, is your metal coolant lines. Just go underneith, and give them a twice over (not once over, look close!) check for kinks, bends, dents, dings, anything that can restrict coolant flow

The next thing, get your engine up to operating temp, and feel your upper radiaator hose @ the radiator, is it hot? feel the lower one, is it close? if not, you might have a clogged radiator, stuck thermostat, bad water pump, or air bubble. Something is restricting flow! if it IS hot, burp the system, and give another check engine hot.

Lastly, measure temps on the radiator surface with an Infared Thermometer, read the top and bottom of the radiator, along with side to side, the numbers should show the coolant is being cooled, if not, you got a clogged radiator! However I HIGHLY doubt your radiator is clogged, I bet you they did something under your car without you knowing.

It is common for crooked automotive techs to ruin something so that they can get more money on another repair job. Guys have been caught injecting water into ball joints and rod ends, putting sealer into coolant systems, putting water in the gas tank, and foreign matter into A/T's. You might have just gotten the shaft from a crook as there is nothing about recharging an A/C system hat would cause overheating with the systen turned off.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

quote Originally posted by Marvin McInnis: The fact that you were running without a thermostat and seeing temperatures over 200 F even before you had the AC charged tells me that the cooling system wasn't working right before and isn't working right now. My '88 (Formula) runs at a very consistent 200 F (+/- 5 degrees) with a 195 degree thermostat ... whether the AC is on or not. If your car overheats with the proper thermostat installed there is something wrong with the cooling system, not the AC. You need to find it and repair it. Fixating on the AC will not help.

My car ran @ 185* wiithout a thermostat and ~220* with a Bad one (crushed). I removed the bad thermostat and drove it to the AC shop with NO issues 185* and when I get the AC charged then I have overheating issues. I was watching the guy most of the time so I don't think he did anything fishy.

It boils down to this, lol, stop trying to guess what the problem is and go check your car like all these knowledgeable folks have advised. Lots of these checks are free and even though your first instinct is correct (that something about charging the a/c caused the problem) if your car is overheating with the a/c turned off then you appear to be a victim of coincidence however unlikely. If you find the problem, please report as this thread is interesting...

Charlie

So since it overheats with the AC switched off what do you think is the issue?

------------ edit ----------------

(Interesting enough that two people were writing responses at the same time at 3 AM)

[This message has been edited by phonedawgz (edited 08-27-2010).]

Ok, so I go back to the AC tech this morning and the car slowly but steadly climbs to 249* by the time I park it for them to check. The car was NOT overcharged, 30 PSI on the low side and I don't remember the High but it was NOT over 200 PSI. I had the tech remove all the freon and that is when he noticed that The freon was 1/3 gone sugessting a massive leak somewhere, they put die in the so they can find the leak, but didn't have time to do that yet. I drove the car back home about 3 miles and it DID NOT overheat. The temp stayed between 199* and 228*. It wend down to 199* when driving and up to 228 while @ a light. My Factory temp guage is pretty accurate according to my Aeroforce digital scan guage. It usually settles in halfway between 0 and 220 mid point mark, or 1/4 of the way. The car averaged ~213* for most of the way. I will remove the thermostat and see the results after that. It seems to be driving with the temps in the same range as when my last thermostat was crushed.

[This message has been edited by nosrac (edited 08-27-2010).]

quote Originally posted by nosrac: I am not a mechanic so I can only speak from what has actually happened to me and not even sure why. But...When my truck started overheating it was caused from something in the engine (blown gasket or bad compression in one cylinder or something like that) and I had to get the engine rebuilt. The car overheating was a result from somehing wrong with the engine. So my point is this: Can't high pressure in one seperate area Engine, AC cause issues in another, ie cause car to overheat.

No. The AC is not causing your problem if you are running so hot when the AC is OFF. Forget about the AC for now, you need to look at the cooling system and figure out what is causing the car to run hot. The AC, when OFF, is not adding any heat load to the engine. The condensor in front of the radiator is not shedding any heat when the system is OFF. I think you have to start with the simple stuff, is the cooling system filled properly? Thermostat correct and working properly?

quote Originally posted by TONY_C: No. The AC is not causing your problem if you are running so hot when the AC is OFF. Forget about the AC for now, you need to look at the cooling system and figure out what is causing the car to run hot. The AC, when OFF, is not adding any heat load to the engine. The condensor in front of the radiator is not shedding any heat when the system is OFF. I think you have to start with the simple stuff, is the cooling system filled properly? Thermostat correct and working properly?

I understand your point that the AC will NOT cause the car to run Hot when it is OFF but how do you explain it running normal temp (190* ~ 220*) before the charge and also after I had the freon purged from the system ? It makes sence from a logical troubleshooting standpoint that the culprit is the Freon. Normal temp before I added the Freon, Overheated when it was in the system and then returned to normal temp when it was removed. There is definetly a major problem with my AC, a major leak somewhere in the system. I'm no AC mechanic and everyone is telling me it is NOT the Freon that is causing the problem. Ok, so what could it be, that is AC related? Did you read my links that some ppl experienced the same problem when they added the Freon?

[This message has been edited by nosrac (edited 08-27-2010).]

I agree it doesn't make any sense but it has to be a co-incidence. The Freon does not come in contact with any other system in the car.

quote Originally posted by nosrac: ... I'm no AC mechanic and everyone is telling me it is NOT the Freon that is causing the pronblem. Ok, so what could it be?

The AC and the engine cooling system are two totally independent systems, except that the radiator and the AC condenser share the same airflow. Go back to the beginning of this thread and re-read the suggestions that many experienced Fiero owners have taken the time to post for you. There are also literally hundreds of threads in the PFF archives that address this topic.

The "crushed" thermostat alone is enough to establish that you have a cooling system problem, not an AC problem. The Fiero cooling system has its quirks, but it's still not that complex A healthy Fiero cooling system with a 195 degree thermostat will still maintain stable engine temperature on a 100+ degree day, even with the AC running full blast. Mine does. Yours can too.

hmmm, bad radiator, crushed pipes, air in the coolant, bad water pump, bad or missing thermostat, bad coolant, bad radiator cap, bad temp sending sensor.


The A/C shouldn't cause a problem. The easiest thing to test when you have freon on is to disconnect the compressor. I believe you can just disconnect the plug in front, by the accumulator. Otherwise, pull the belt off of the compressor when the A/C is charged. That way you know the compressor isn't turning when driving.

But also to make it clear, an overcharged AC system can/will overburden/ overheat the engine. It will however only do it while running.

quote Originally posted by jaskispyder: Oh, as mentioned, the thermostat isn't crushed, it was pushed from the coolant. Something is running too hot (as we suspect). You could also have a bad head gasket.

bad head gasket... .... Please not that...

So the t-stat is NOT crushed? Is coolant pushing the t-stat normal? It looks pretty jacked up to me...LOL !

quote Originally posted by nosrac: bad head gasket... .... Please not that... So the t-stat is NOT crushed? Is coolant pushing the t-stat normal? It looks pretty jacked up to me...LOL !

Crushed seems to be the wrong word, and I just wanted to make it clear that the thermostat was pushed by the coolant from the engine.... the thermostat was the weak point because of the coolant's need to expand.

I am only stating the head gasket, as gases during the compression cycle could be pushed into the coolant jacket.

J.

When the engine is cold the thermostat is fully closed and that is normal operation so any explaination that involves a stock water pump and somehow the tstat is closed when it shouldn't be doesn't, ah, hold water. However with the t-stat just cracked open when a pocket of air hits it the less resistance of the air will let the circulation speed up. That is untill the air pocket is through the crack and then the liquid hits it. If you ever drained the water pipes in your house you saw that happen at the faucets first time you opened them.

quote Originally posted by phonedawgz: The way I see it the only thing that would bend the thermostat would be 'air hammering' caused by air in the system.

It could also be caused by a blocked heater circuit. The heater loop serves as a thermostat bypass, and thus acts as a crude "safety valve" for pressure across the thermostat. The heater loop also guarantees a base level of coolant circulation in the block and heads, thus minimizing hot spots while the thermostat is fully closed.

A blocked heater loop will also cause the back pressure at the water pump to be much higher than normal, which just might be enough to cause a plastic pump impeller to loosen on its shaft.

[This message has been edited by Marvin McInnis (edited 08-27-2010).]

quote Originally posted by jaskispyder: hmmm, bad radiator, crushed pipes, air in the coolant, bad water pump, bad or missing thermostat, bad coolant, bad radiator cap, bad temp sending sensor. The A/C shouldn't cause a problem. The easiest thing to test when you have freon on is to disconnect the compressor. I believe you can just disconnect the plug in front, by the accumulator. Otherwise, pull the belt off of the compressor when the A/C is charged. That way you know the compressor isn't turning when driving.

I go with this one right here.
Clogged radiator or worn water pump.
Is your car a V-6 or a 4 cylinder?
4 cylinder pumps can run enough fluid without A/C on and keep up but when the A/C is on they can't keep up.

Clogged radiator on any engine can't cool enough to keep temps down.

[This message has been edited by Indiana_resto_guy (edited 08-27-2010).]

You mentioned that the AC isn't that cold when it was working. What did you have done exactly? What parts were changed? I was thinking that maybe there is some trash in the system and your condenser is partially clogged. That could cause a lack of airflow to the radiator whether the AC is running or not. Not as likely as a cooling issue but something to think about anyway.

quote Originally posted by TONY_C: You mentioned that the AC isn't that cold when it was working. What did you have done exactly? What parts were changed? I was thinking that maybe there is some trash in the system and your condenser is partially clogged. That could cause a lack of airflow to the radiator whether the AC is running or not. Not as likely as a cooling issue but something to think about anyway.

Took it to a AC repair shop and they hooked it to a machine. It worked on the 3 mile ride home and around the neighborhood but didn't feel that cols on a 95* day. It still worked this morning but not as cool as yesterday.

"condensor is partially clogged" sounds on the money to me. Would that issue arise when Freon is added or the system is charged?