95 E300 compressor worth an upgrade? - Page 2 - PeachParts Mercedes-Benz Forum

leathermang · #16 05-31-2016, 10:09 AM

OK Carl, that is great... I could not figure out what kind of malfunction could cause condensation on the condensor... lol

carl177 · #17 05-31-2016, 11:19 AM

No worries Leathermang, When writing - no matter how hard one tries to cover all corners and provide a clear picture of your findings, you usually end up with a few corners being left out, I apologize ahead for that.

Thank you for the feedback, I quickly asked my dad to take a look at the car this morning, and he mentioned that the fins have a few minor gills that are not straight but that it was mostly looking A OK perhaps at about 90% at this time; I am going to follow your advise and get a fin radiator comb to clear out as much as one can on the ones that are not; 95% surely beats 90% after all.

leathermang · #18 05-31-2016, 11:48 AM

Carl, Those combs are great in many instances....but often not in confined spaces.... it might be just as well to use a sharp instrument... you just start at the first one and bend it out strait and then pull the next one up...
Between the condensor and the radiator you can use a mirror and something long with a 90 degree blade on it... it is slow but does not have to be done often... unless you hit lots of stuff...

leathermang · #19 05-31-2016, 11:51 AM

Carl, I do not see an indication that you have put gauges on your system ????

Zulfiqar · #20 05-31-2016, 11:52 AM

I have no problem with A/C cooling in my 95, the only time it started to act like this was when the Aux fans resistor burned up and even took out the slow speed part of the circuit (although intermittently).

as leathermang said - first a gauge hookup can tell you lots of information within an A/C unit - then do a test, when the car is running with A/C at load and engine hot, rev it up - does the engine fan roar?

then do another test, reverse the car for a few feet, does the air get warm? - if it does then your aux fans are probably not working when required. Even with them at low rpm they are enough to cool down the condenser.

97 SL320 · #21 05-31-2016, 04:22 PM

If variable displacement, towards the rear of the compressoe ,there should be a 1 1/4" or so plug held in with a snap ring.

https://www.polarbearinc.com/Articles/Variable%20Displacement%20Compressor.pdf

97 SL320 · #22 05-31-2016, 04:32 PM

The last post in this thread claims that high side pressures were too high with the larger compressor. I'm not sure that was due to a larger displacement compressor since variable displacement will maintain a constant high side pressure since that is the design intent.

Engine swap, new engine has larger compressor, charge weight more/less? [Archive] - Refrigeration-Engineer.com forums

This thread shows that someone made the 15 - 17 swap but didn't follow through with an update.

W124 larger A/C compressor -- Same harness?

carl177 · #23 05-31-2016, 08:03 PM

Leathermang - I myself have not had the gauges put in the car. I have taken it to the A/C guy that replaced the evaporator a few years back and he says that the pressures are right on. (I didn't ask for the pressure reading as they would be Chinese to me pretty much, I also had the car checked out at the dealer as I know a few folks there; And they said the pressures were spot on. (The thing is that the mechanics bay in the dealer is in a controlled environment (under A/C) the cars AC while in there works wonderful even while the car is parked)

I have made the A/C gentleman that replaced the condensor a few years back leave the car under the sun all day and have him turn it on to see what he gets. He says that it's cooling ok and that the pressures seem perfect.

This behavior tends to happen when the outside temperature here when over 92 degrees is when the air stars getting nowhere.

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carl177 · #24 05-31-2016, 08:17 PM

Zulfi - thanks for chiming in buddy. As far as the auxiliary fans go here and while the A/C is in automatic, they never shut off (here in Miami, it's hot and there is a lot of humidity) the only time that I have seen them alternate on and off is when the fan speed is set to low and the temps here are below the seventies. (Mostly in January, February mornings when the sun is barely out in all of its glory) I can confirm that they are both working and spinning evenly.

The fan clutch is new (MB Unit) I had replaced it with a Behr unit about two years ago and I found that just wasn't responding; The new one seems to be working properly. The temp gauge never reaches what I believe to be 100 (the numberless line before 120) occasionally and when paying attention I hear it roar (sounds awesome by the way)

Again thank you all for your suggestions and ideas.

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carl177 · #25 05-31-2016, 08:24 PM

97 SL320 - thank you for the information on the compressor I can understand now a bit better when you mentioned that your 97 C280 had a volume problem with the old compressor.

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carl177 · #26 05-31-2016, 08:30 PM

Jeremey5848, that is a pretty clever thing that you did there with the lights. For some reason I always figured that once you get the car going the auxiliary electric fans would just shot off because of the ram air effect and not just keep on going at those speeds. (One surely learns something everyday)

Again I want to take the opportunity to thank you all for the information, ideas and advice.
There is a great wealth of knowledge and that along with good folks that are willing to share it is simply priceless.

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carl177 · #27 05-31-2016, 08:37 PM

In the next couple of days I am going to put the car in the shop for a little body work courtesy of the P/O that has been bothering me for a while. This will unfortunately leave me with limited access to the car.

But I will try to get a hold of a set of gauges, and get pressure readings to post those here along with the ambient temperatures to hear what your thoughts are.

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leathermang · #28 05-31-2016, 10:09 PM

For a good test you need a really good squirrel cage blower right at the grill....on high...
Windows open, blower on low, thermometer in center vent, high idle....

Zulfiqar · #29 06-01-2016, 10:23 AM

Quote:

Originally Posted by 97 SL320

If variable displacement, towards the rear of the compressoe ,there should be a 1 1/4" or so plug held in with a snap ring.

https://www.polarbearinc.com/Articles/Variable%20Displacement%20Compressor.pdf

The W124 did not use the variable displacement compressors like the later benz had, they had the oldschool 100% duty cycle pumping units.

Zulfiqar · #30 06-01-2016, 10:25 AM

Quote:

Originally Posted by carl177

Zulfi - thanks for chiming in buddy. As far as the auxiliary fans go here and while the A/C is in automatic, they never shut off (here in Miami, it's hot and there is a lot of humidity) the only time that I have seen them alternate on and off is when the fan speed is set to low and the temps here are below the seventies. (Mostly in January, February mornings when the sun is barely out in all of its glory) I can confirm that they are both working and spinning evenly.

The fan clutch is new (MB Unit) I had replaced it with a Behr unit about two years ago and I found that just wasn't responding; The new one seems to be working properly. The temp gauge never reaches what I believe to be 100 (the numberless line before 120) occasionally and when paying attention I hear it roar (sounds awesome by the way)

Again thank you all for your suggestions and ideas.



The best inside story would be found when a gauge manifold is connected to the system, Im thinking its low on refrigerant. Also make sure your heater valve is not malfunctioning - if it lets hot coolant into the core, your A/C would be warm performance.