just got my a/c fixed put in a new condensor and charged a/c up and now my car runs hot? temp is 230 and up? i put in a new water pump and new radiator and new thermostat. it only runs hot when a/c is on. what is the prob help me!! lol

 

- Have you checked all your wiring connections? If I remember right, the "coolant temp sensor" is right below the MAF on the block and may have bumped the wiring connection during install of the water pump. If disconnected, it may mess with the cooling logic.
- Do you have any codes? Checked all the fuses?
- Are the radiator fan(s) running? If you put the car in diagnostics mode, the fans should turn on right away at key turn on.

 

My fan is on a toggle switch. It did have a fan in front of the condenser but it fell off. I think it was a auxillary cooling fan. It is not giving any codes

 

Is your fan on as soon as the a/c is on? Might want to remount the pusher fan.

 

will it run hot if the pusher fan is not on? it only does it when the a/c is on?

 

The pusher works in conjunction with the regular fan on the engine side of the radiator to keep temperatures down. It could be the difference in your case.

 

ok thanks. it was geting so hot it ran out the puke tank bad. it would run at 180 to 200 with the a/c off but as soon as i turn the a/c on it starts to run up to 230 to 240?

 

normal temp for your car should be:
A/C off, 232 is where the fan comes on, it shuts off at 215.
A/C on, 225 is where the fan comes on high, it shuts down to med. at 210.
But;
when you first start the car with A/C on, no fan for 15 seconds, and it should run at medium speed. When the temp climbs, it should kick into high.
If I were you, i would change the fan relay. It sounds like there is resistance on the contacts and they may be burnt.
A new relay would allow your fan to go it's fastest speed at low vehicle speeds.

The aux fan that fell off is there for your comfort. It blows cooler air on the condenser so the freon temp does not rise and the high pressure switch shut off the compressor.
it's a nice thing to have.
BTW, I wired the coil of the aux fan relay to the power wire of the main fan. That way, when the big fan comes on, the little one will too. Wiring the coil to the power wire will only increase the load on the fan relay circuit about 1/10th of an amp, and it should be almost non existent load. Power the aux fan relay from the battery connector behind the battery on that little battery junction block.

 

Ok. The last owner wired in the toggle switch for the radiator fan.

 

Stop thinking about Coolant Temp and start thinking about the temp of the liquid you're making in the Condensor. It needs to be around 125 degrees (well below any thermostat or coolant temp that your engine needs) and it gets there shortly after the compressor engages regardless of Coolant Temp. To control that, there's a switch on the High Pressure Line that opens the voltage reference from the ECM causing a voltage rise at the ECM. With that, the fan engages and remains engaged until the Condensor temp is below that 125 degree threshold. At that point the switch closes, the reference drops to zero because it's grounded and the ECM removes ground from the Fan Relay. When it's right - assuming your a/c system and cooling system are as close as they can be to the day it left the Factory - you'll get cold air out of the Vents and Coolant Temps 8 to 12 degrees less than they would be if the a/c wasn't on. Start by finding that a/c fan switch which is mounted on the high line next to the high pressure cutout (there's only one wire to this switch). Disconnecting it simulates the open and the fan should come on. That verifies that the ECM is working. Then hookup a manifold gage set and when the high gage shows 230 psi, the fan should come on. If it doesn't - or never comes on - get a new switch. If it comes on and the pressure keeps rising, your a/c system is mucked up and needs attention. There is no dual speed for this Year nor is the Aux Fan linked to a/c. If you want to use a manual switch, you'll need something to tell you what the Condensor pressure/temp is or you'll risk blowing a hole in the hood.

 

My all stock 1986 had the same issue, if it was hot outside and I turned on the air even with the pusher fan it would overheat if I ran through town. The cooling system on these cars is marginal at best. I put in a larger radiator to finally fix the problem for good.

 

Did this change for 88? the aux and main fans both come on with a/c, and at 228 the main one comes on by itself.

 

Nope - not until '90 when the OEM's started to gear up for R134 which takes a lot more air flow to control at higher outside air temps (and they still had 4 years to monkey around with it and get it right). Someone has spliced your Aux and Main Relays together. Quite common back in the day - hell I even tried it since it was plastered in every Vette publication that was out there - but all that accomplishes is electrical overload and when the voltage drops, both fans slow down, and with that, it overheats. I'd get rid of it so that the puny alternator (relatively speaking) can handle the load it was designed for: 1 fan, 1 compressor & 1 Blower Motor at full tilt. You usually get better temps - both Coolant and out of the Vents. If yours doesn't work this way - with 1 fan - something else is broken, and also make sure you've got at least battery (with 1 fan) with everything on because sometimes, that's where the problem lies.

 

but i dont know y it just started this.it did not do it befor i changed the Condensor and the aux fan broke?

 

Its because your new a/c condensor is super-heating for whatever reason and that heat gets blown directly into the radiator.

Look at the 134a charge. Its supposed to be about 90% of what the r-12 charge was. Thats not exact and some systems operate best with a few oz less. Too much and there is less gas/liquid/gas exchange where heat is transfered in the condensor.
You may also want to look into a better air dam, a different (correct) expansion valve and how much oil is in the a/c system. Too much oil causes too much liquid at the wrong time/place. The key to decent 134a conversion is airflow and gas pressure on the high side. The higher it is the hotter it is.
Even with a new condensor it needs fresh air to work. That only happens at 25 mph+ on hot days of 90 ambient or more. Since the C4 scrapes its fresh air off the hot streets...its challenging at best to get enough fresh air to cool the condensor AND radiator.
Feel what the fan is pulling out of the radiator ! Half that is condensor air.

The hotter the ambient the less differential there is. 200 is cooler than 210 but see how long it takes for 210 to drop to 200.....forever.
When your condensor is running at 250....its darm hard for the radiator to run at 200 with the hot air blowing on it.

I have a similar problem and my whole a/c system firewall forward is NEW.
I'm toying with the idea of installing some other type of fan in the nose to pull air up and inside to be aimed at the condensor...but space is limited as you know.
Bottom line, these 134a converted systems are marginal at best and with r12 prices coming down, and 30 lbs sitting in my brothers garage...I'm thinking of going back. I'm sick of having my shirt stuck to the seat....zgo back and check your pressures and see if less would do more. Finding some more fresh air will help too.

 

so you think i need to remove some of my R134? to help it cool down?

 

you have to decide that based on the info given. If the condensor is super-heating......its blowing that very hot air (250 degree+) to the radiator. you're never going to run cool like that.

one problem comes from the other.

 

R134 at 250 degrees is about 500 psi and you've long since blown a hole in the hood if the compressor is still running. On the other hand, R134 at 250 psi is 146 degrees, but with subcooling (superheating occurs as it changes from a liquid to a gas and that's in the Evaporator, not the Condensor), it's closer to 130 degrees. Both temperatures are well below the thermostat. A 1 to 1.5 inch clearance between the Condensor and the Radiator allows for sufficient heat transfer and your coolant temperatures should be controlled by the thermostat. I'd aim for a high side pressure that's no more than 2.5 times the temperature at the condensor so if it's 100 degrees there, a high side of 250 psi would be max. If you're not blowing cool air, take a look at the low. R134 is 32 degrees at 28 psi; 45 degrees at 40 psi; 54 degrees at 50 psi, and 62 degrees at 60 psi. Overcharged or mucked up conversions allmost always show a low above 50 psi - some guy around here posted a 65/70 psi.

 

250 degrees was just a number used to drive home the point. Meaning that if the condensor was getting hotter than it should, that heat lowers the radiators heat exchange when the temp differential is negated by condensor excess heat. If the condensor is running at a "normal" temp then the system can function, but if its 50+ degrees above normal, then that takes away from what would be exchanging with the radiator. The 1.5" air gap allows some air to flow around the condensor, but next to NONE at a stop lite. The pusher fan does'nt move very much because its not shrouded and the sucker pulls thru the radiator not the condensor, so the system goes to high pressure and cooks as all cooling is lost while there is no air-flow thru the nose from motion...about 25-30mph.

Because I have an oil cooler in front of my condensor mine must be moving to have working a/c when its 90+ ambient. Otherwise its just hot air off one thing blowing toward the next....

Thats why I suggest the OP to go back and look at his pressures and see why his condensor is running so hot when its new. I know it is since he states that the car temp is normal without the a/c on. The extra 40 degrees operating temp is coming from the condensor. And, I was wondering....if op temp normally was 190, w/o a/c and with a/c it shoots up to 230 or more at low speed, that means there was an increase of around 40 degrees? So if the engine now wants to run at 230 or more and can't cool down from there with the a/c on, would';nt that indicate a condensor temp of well over 200..? From over-charge perhaps ?
Just asking....

 

yes it only does it with the a/c on.When the a/c is off it never gets over 200.I have a 160 temp thermostat and it is a new 1.And I would like to thank you guys for all the help