My Benz E500 (1993 model) does over-heating whenever I put on the AC, What could possibly be wrong here.

many things can cause it
firstly:have you been using the a/c before if yes,check this
1]a  bad thermostat can cause a car to overhear when a/c is on,
2]bad radiator cap
3]if the a/c is not factory one
4]fan, well the car should have 2 fans or one big fan that come with the radiator.try to check when  you start the engine does the fans work because most  cars has 2 fans and only one work whenver the engine is on and the second after the a/c is on.check if the 2 work when the a/c is on.
thanks

I don't believe the AC has anything to do with overheating.

First if you are loosing coolant, find leak and fix(might even be radiator cap). If your engine oil is foamy/milky head gasket leak replace or save for another engine.

Check cooling fan, turn on engine and watch the temp. If fan does not come on before temp gets halfway your(fan) sensor/relay is toast, or thermostat it failed close(find & replace) with fail open thermostat.

If your cooling fan is working, replace your water pump and flush engine+radiator (preventive service that has to be done) use coolant and DI/distilled water(you can get it from condenser hose of home/office AC its not good to use any other water)

what temperature is it geting up to?
Ac has nothing to with that.
i suspect low coolant/ wrong concentration
head gasket or faulty fans

Take it to your mechanic or garage and have it check out and fixed properly for you rather doing self daignostic which might lead to more problem.

1993, bros the car is crying for retirement after 14yrs of active service.
sell it and buy any fairly used the money can get you.

@Poster

First of all, you have a dynamic beast!  I'm currently looking for an E500 and you're lucky.  I'm currently looking for one.  1100 were made worldwide.

It may not be overheating.  The fan doesn't come on till it reads 100degC.  It will flunctuate from 80 to 100.  The ideal temperature is 90degC.  0W-40 is the oil weight and synthetic. 


M103's and M104's are known for a bad head gaskets after 100,000 miles, no matter how you take care of it.  The reason is that MB phased over to biodegradable components and the heat in the engine bay wouldn't let it stand the test of time.  You are going to be loosing compression as well.  In addition to it, you should always use the MB coolant.  The green coolant cannot convent the heat and you'd also be running hot.  There is no substitute except you use Zerex by Valvoline.  All E series/E Classes from 86 to 97 (300 and up) have a head gasket issue.  '93 should be 500E and M103 in engine code.  You can hit two birds with a stone and have no timing chain replaced.  No additional labour.

hbrednic:

1993, bros the car is crying for retirement after 14yrs of active service.
sell it and buy any fairly used the money can get you.

You must not know the meaning of over-engineering. The car is designed for 50 years, 1 million miles. That Mercedes was designed in partnership with Porsche. It's the last pinacle in automobile and motorsport history before the E12.

ikorodu:

what temperature is it geting up to?
Ac has nothing to with that.
i suspect low coolant/ wrong concentration
head gasket or faulty fans

Low coolant will force the vehicle to limp mode. Extremely low will cause the ECU to stall and shut down the vehicle to prevent engine damage

sultaan:

I don't believe the AC has anything to do with overheating.

First if you are loosing coolant, find leak and fix(might even be radiator cap). If your engine oil is foamy/milky head gasket leak replace or save for another engine.

Check cooling fan, turn on engine and watch the temp. If fan does not come on before temp gets halfway your(fan) sensor/relay is toast, or thermostat it failed close(find & replace) with fail open thermostat.

If your cooling fan is working, replace your water pump and flush engine+radiator (preventive service that has to be done) use coolant and DI/distilled water(you can get it from condenser hose of home/office AC its not good to use any other water)

doesn't have a radiator cap. It's a white cell intercooler with a reservoir that isn't dependent on the cap. MB coolant shouldn't be mixed. The head gasket is the achilles heels on that model. Butter or milky solution coolant depicts oil is being mixed.

Peace, y'all.