W126 Redid ac system and it's barley cold - Page 2 - PeachParts Mercedes-Benz Forum

Hit Man X · #16 07-07-2017, 04:48 PM

My 1991 560 does not have a factory PF. It has dual fans, which came standard around late 1989. The 300SEL also has dual fans. SDL is setup just like the SD.

The '85MY SD, like mine, has the smaller tube condenser and larger aux fan already along with the smaller water pump pulley. OP's issue is high humidity, no tint, and high ambients...even new vehicles struggle with that. I deal with high humidity and high ambients here, but my SD is tinted deep which helps huge. OP's system is working as designed to me.

In my experience, those $1 sun shades are really floppy and will not retain shape. They help some, but not as much as the stiff ones. Those $40 ones have a two year warranty, not as long as I had hoped for the extra cost.

Ncbenz · #17 07-07-2017, 09:17 PM

Quote:

Originally Posted by Hit Man X

My 1991 560 does not have a factory PF. It has dual fans, which came standard around late 1989. The 300SEL also has dual fans. SDL is setup just like the SD.

The '85MY SD, like mine, has the smaller tube condenser and larger aux fan already along with the smaller water pump pulley. OP's issue is high humidity, no tint, and high ambients...even new vehicles struggle with that. I deal with high humidity and high ambients here, but my SD is tinted deep which helps huge. OP's system is working as designed to me.

In my experience, those $1 sun shades are really floppy and will not retain shape. They help some, but not as much as the stiff ones. Those $40 ones have a two year warranty, not as long as I had hoped for the extra cost.

Thanks man I guess i price out some tint and a sunshade. As long as it sounds normal I'm happy.

leathermang · #18 07-08-2017, 08:15 AM

A Sunshade INSIDE the car may help protect the upholstery and stuff from sun damage...but I am pretty sure it does not reduce the heat getting inside the car...
A nice partial car cover just for the glass would....preferably white...

tyl604 · #19 07-08-2017, 09:27 AM

Not sure about tint but I can tell you absolutely from experience that the reflective removable windshield screen makes an incredible amount of difference. I worked in Norfolk, VA, for two years and my car sat in an open lot all day. I used a $1 screen from Dollar Store and it made an incredible amount of difference.

So in my view the other alternatives make little economic sense.

Diseasel300 · #20 07-08-2017, 10:40 AM

Quote:

Originally Posted by leathermang

A Sunshade INSIDE the car may help protect the upholstery and stuff from sun damage...but I am pretty sure it does not reduce the heat getting inside the car...

Anything to block the sun coming in through the windshield and rear window can make a PROFOUND impact on how hot the interior of the car gets. Even a piece of cardboard can make a big difference. Blocking out the sun prevents radiant heating of the dashboard, plastics, and interior of the car, so the only heat you get in the cabin is due to conduction and convection from the car exterior and side windows. With the sun beating down on the dashboard and interior, everything being solar-heated becomes its own little solar space-heater.

Using those cheap Mylar "sheets" you get a Wal-Mart makes about a 50˚ difference in my all-black Honda. Coupled with the tinted windows, it means that my cabin cools down by the end of the main road leading up to work vs cooling down just as I turn into the driveway when I get home. Obviously not every car will have results like that, but a black car with an all-black interior is a worst case example.

Another helpful hint is to leave the windows cracked 1/2" or leave the sunroof popped to the "vent" position.

funola · #21 07-08-2017, 03:50 PM

I don't think your AC is behaving normally,, at least not compared to my 85 300D. I just ran mine idling for 10 min @ 85 F ambient. sunny out, no tint no sunshade and it got down to 47 F at the center vent with blower on medium hi after 10 min. I recharged it with 2.9 lbs of R12 last week after replacing the noisy R4 with a reman 4 Seasons R4. All orig hoses condenser and evap. new orings txv and dryer last summer. The reman R4 is nice and quiet.

leathermang · #22 07-08-2017, 05:09 PM

Quote:

Originally Posted by Diseasel300

Anything to block the sun coming in through the windshield and rear window can make a PROFOUND impact on how hot the interior of the car gets. ......

Do you understand that I was saying that if it has entered the car...that it is already there inside the car ?

You are correct that anything BLOCKING the sun from coming through the glass is very helpful.... I was addressing the inside articles....like dash covers and package tray covers....

Hit Man X · #23 07-08-2017, 06:33 PM

Quote:

Originally Posted by Diseasel300

...or leave the sunroof popped to the "vent" position.

If you trust yours to reclose properly.

Ncbenz · #24 07-09-2017, 10:15 PM

Quote:

Originally Posted by funola

I don't think your AC is behaving normally,, at least not compared to my 85 300D. I just ran mine idling for 10 min @ 85 F ambient. sunny out, no tint no sunshade and it got down to 47 F at the center vent with blower on medium hi after 10 min. I recharged it with 2.9 lbs of R12 last week after replacing the noisy R4 with a reman 4 Seasons R4. All orig hoses condenser and evap. new orings txv and dryer last summer. The reman R4 is nice and quiet.

Hmm then something might be up. Since the pressures are right and I've assured no heat is blending, I'm lost.

I parked my car in the garage today and by the time I got driving the vent temps were very low, with ambient of 80f.

Diseasel300 · #25 07-10-2017, 08:13 AM

The A/C system isn't magic, it takes a bit of time to do its thing. Vent temps are a function of system capacity and intake air temperature. If the cabin is warm, it has to pull the temperature down before the vent temps will drop. This means you have to drive around a bit before you get "cold" air at the vents, but it shouldn't take any longer than ~5 minutes to cool the car off.

Make sure your recirculation flaps are fully closed and sealed off. If the fan is pulling in outside air, your vent temperature will rise accordingly.

Lastly, make sure your coils are clean, both the condenser and the evaporator. Dirty coils will greatly hinder your overall system performance. I cleaned my evaporator this weekend and what a difference it made in how quickly the car cooled off.

You have the right charge, you have the right pressures, so stop looking at the system, look to see what may be hindering its operation (dirty coils, outside air ingress, etc).

leathermang · #26 07-10-2017, 09:36 AM

Quote:

Originally Posted by Diseasel300

...... I cleaned my evaporator this weekend and what a difference it made in how quickly the car cooled off.....

I am sure that this is the most overlooked AC fix on this forum..
If people just understood how much difference it can make.. they would go to the trouble to address it ..... often our cars are more than 30 years old and that has NEVER been cleaned....

pj67coll · #27 07-10-2017, 10:48 AM

Quote:

Originally Posted by leathermang

I am sure that this is the most overlooked AC fix on this forum..
If people just understood how much difference it can make.. they would go to the trouble to address it ..... often our cars are more than 30 years old and that has NEVER been cleaned....

Not that easy to clean surely? Don't you have to remove half the cars interior to get to it?

- Peter.

funola · #28 07-10-2017, 10:56 AM

Quote:

Originally Posted by Ncbenz

Hmm then something might be up. Since the pressures are right and I've assured no heat is blending, I'm lost.

I parked my car in the garage today and by the time I got driving the vent temps were very low, with ambient of 80f.

What was "temps were very low"? I think I read somewhere that if you can get the temps to drop 40 (or is it 45) F from ambient, your AC is working well.

Ncbenz · #29 07-10-2017, 04:41 PM

Quote:

Originally Posted by Diseasel300

The A/C system isn't magic, it takes a bit of time to do its thing. Vent temps are a function of system capacity and intake air temperature. If the cabin is warm, it has to pull the temperature down before the vent temps will drop. This means you have to drive around a bit before you get "cold" air at the vents, but it shouldn't take any longer than ~5 minutes to cool the car off.

Make sure your recirculation flaps are fully closed and sealed off. If the fan is pulling in outside air, your vent temperature will rise accordingly.

Lastly, make sure your coils are clean, both the condenser and the evaporator. Dirty coils will greatly hinder your overall system performance. I cleaned my evaporator this weekend and what a difference it made in how quickly the car cooled off.

You have the right charge, you have the right pressures, so stop looking at the system, look to see what may be hindering its operation (dirty coils, outside air ingress, etc).

I already cleaned the coils on both the condenser and evaporator. So think I'll make sure the recirculation flap is staying open. The wierd thing I've noticed recently is it the temp will sometimes be cold and than later in the drive be only cool. This is on max ac.