Las Vegas HEAT Leaving Me Stranded with A/C running
 

Las Vegas HEAT is taking Over my Mercedes: PLEASE HELP !!!
1993 300E with 168,000 miles. New water pump last summer; Zerx G-05 coolant: New ignition coils (3) and wires and spark plugs. Last week New expansion tank CAP and recent OVP relay.
Currently in the midst of 30+ consecutive days of 100 degrees or Hotter.
NOW my Issues. Car starts fine Cold But when using A/C ; as operating temp Rises Car starts strange behavior. Once temp guage gets to about 110; Car is sluggish and performance drops Drastically. When i shut car off and come back shortly : It is hard to start - it cranks but turns over as if i am out of gas. I Have to pump accelerator to get it to start and then it goes into SURGING Up and Down Idle and then sometimes even cuts off(Stalls) as i try to pull off. Does the hard start again and when it does start i have to let it idle for couple minutes before taking off. ALSO sometimes when i come back to car after having driven a while and shutting it down; It will actually blow HOT air instead of A/C ( I know AC works because it was blowing nice cool Air before engine got so Hot. I then have to turn AC OFF and drive in 110 outside temp with windows down ;NOT a good drive . As a test i drove same route withOut AC on ;And engine temp gauge slightly goes past 100 and i DONT get the sluggishness issues OR the Hard starts/stalling as i did when running the AC on same route. Basically car runs pretty good Without AC BUT driving without AC is NOT an option because of weather outside (HOTTT)
Also Both Aux Fans are Running Most of the time;Actually they kick on a short time after cold start in mornings;and engine is still HOT most times after that so when i start up later; aux fans come ON with start. Once attempted to Recharge freon But gauge on Can showed freon in the Fully Charged section.
All Help and Advise is Truly Appreciated as this issue issue is driving me crazy As well making for Very Unpleasant Driving of my BeLoved Benz. THANKS ALL.........................

i think most on here will tell you to check your pressures.... my guess is you need a half a can of your favorite elixir to top it off..

i know in florida... if i don't have my car garaged.... it takes awhile for the a/c to be cool..

in the garage....cool from the start...

Lee ............ which 'pressures' are you referring to specifically?? And what do you mean by elixer?? and which one do You suggest?? THANKS for your reply

For the hard hot starts I would check the fuel pressure regulator as I had the same issue on my 1995 Volvo with a similar Bosch system.

The surging idle could also be the idle control valve sticking. I had THAT on the '84 BMW...

Do a search on both these issues and you should get lots of hits

The AC is designed to shut off once the engine gets to 115c. Make sure your clutch fan is in tip top shape and do the cool harness modification to trigger the aux fans high speed earlier. That'll keep you from getting into those extreme temps.
The lack of power is due to the ignition system retarding timing to protect the engine from the heat. These cars were not well though out for Las Vegas heat.

your biggest prob is the car engine getting hot.check that the fan clutch is working.if i lived in vegas i would lock up the fan clutch to run all the time.the extra noise and small extra fuel burned is preferable to a hot engine.with the engine running take a rag and carefully attempt to slow down the engine fan by touching rag on backside[engine side] of fan.if it's not locking up you will be able to stop fan rotation with rag.

How do you lock up the fan clutch? Seems that trick would be good for Texas also...

if you look at fan clutch there is a bimetallic strip at the front.if you use flat blade screwdriver to GENTLY pry up in centre of strip you will see a small pin.it is this pin being allowed to come out that locks up the clutch.what i do is take a ceramic fuse and plce it under the metal strip next to the pin and the clutch stays locked.

adjusting clutch fan
 

I have drilled a 3 mm hole in the thermo plate and installed a screw and nut , cut in was adjusted by tightening the screw so that the fan locks in at around 90C.
this way in stays quiet Fall onwards and activates in short bursts early summer on. The fan roar is intrusive if on all the time.

mak
300se 126

If your cooling system is functioning correctly you should not need to do this, even in Texas. Yes the cars system is not the best, but it will keep you under 95C in traffic if everything is good.

Locking the fan cluthch only eliminates a symtom of the bigger problem. Either the radiator is not cooling efficently anymore, pressure leak somewhere in the system, aux fans not coming on , A/C not charged, water pump bad or thermostat failed.

Just like the cool harness makes the high speed fan come on way sooner it is just a temp fix.

as far as intrusive noise is concerned[from locked fan]isn't that what the radio is for---turn up the volume.

chance2benz, apparently you replaced the 3 coils without replacing the spark plug connectors. I recommend replacing them.

Also, replace the thermostat and see if that resolves the overheating problem.