A/C R134a pressures too high. I'm lost. Ideas? - Page 5 - PeachParts Mercedes-Benz Forum

ps2cho · #61 07-20-2012, 12:25 AM

Huge success guys!

And holy crap the airflow into the cabin improved by 30-40%!!! Especially from the center vents. It literally made me blink a few times when I turned the car on because I am not used to that much air coming at me on high speed.

I'm ecstatic! Can't wait to test it during the day tomorrow and see what difference it makes. I can tell this is going to make a noticeable difference already.

And without further delay! (56k beware if they even exist anymore....

)

Tool-wise you pretty much need nothing more than a selection of screwdrivers, 8mm,10mm,12mm sockets, a plastic pry bar for the trim and some needle-nose pliers.

Total time taken: 1hr dash removal, 2hrs pod replacement, 2.5hrs careful put-back-together + clean.

Air&Road · #62 07-20-2012, 10:49 AM

Great job ps!

When I did mine I was replacing the heater core. As I recall I had to remove the console.

I'll bet we get another excited post tonight after you've had a chance to check temps!

jcyuhn · #63 07-20-2012, 10:54 AM

Yeah, I'm betting he won't feel the need to do the change out of the compressor and condenser after this work. I think the refrigeration is spot on, and with the pods fixed it'll do a great job cooling the car. Betcha it blows in the 30s now.

ps2cho · #64 07-20-2012, 07:45 PM

Well its definitely much better, the cabin is actually cooling down now after some time. Before it was basically only cool where the air from the vents came out.

It was 108F today when I went out to lunch and I was pulling 55F from the vents around the city, so not bad....but I still feel like it needs the R12 refresh to really make it cold. So it seems the vent temps have not dropped, or marginally, but the cabin feels cooler. At the drive through idling for 10mins it was doing 80F from the vents

It struggles hard. It just needs that R12 to get the finishing touch.

ps2cho · #65 07-20-2012, 11:59 PM

On the way home tonight it cooled the cabin so much faster than before -- I am extremely happy with the difference some vacuum pods can really make!

One thing though -- as I was approaching home, I had a very weird squeak/chirping noise coming from the heater box. I thought it was my fan clutch bearing giving out (its on the list to do -- its not bad, but I am always overthinking everything) so I immediately slowed down, but it was definitely coming from the cabin. I turned off the CCU and the noise stopped. Put it back on and it started.

Definitely not coming from the sampler motor or the main pod vacuum unit. I left the glovebox side not complete for a few days so I could monitor everything just in case...glad I did.

Any ideas what the heck this noise is?

Its quite literally a chirp. No particular frequency to it, its random.

urtruelove78 · #66 07-23-2012, 02:01 AM

blower fan. I have same noise and I confirmed it by switching blower fan on/off, heater on ac on, you will only heat it when fan is on low.
Probably lubricating it will solve problem but not sure.

Air&Road · #67 07-23-2012, 09:26 AM

I expected you to post a complaint about forgetting your sweater and needing it.

108 ambient is an EXTREME condition. I did several hours of driving Saturday in 107 or 108, but I wasn't in my Benz. I'm glad I wasn't. If it ever sat in the Sun & heat soaked there would have been no cooling it down.

You're asking a LOT from any a/c in that ambient. It takes a good while in triple digit ambient, for my old car to show 50 at the vent, but it will do it.

ps2cho · #68 07-23-2012, 09:36 PM

You know what...it was only doing the noise on low speed. Just a coincidence it happened the day after the dash removal?

I removed the blower assembly about a month ago to check/clean the evaporator (which was clean) so maybe the first time its moved in 24 years wasn't a happy thing?

Air&Road · #69 07-24-2012, 08:33 AM

ps,

Yeah, sometimes things like this don't like to be disturbed? My Dad was a mechanic when I was growing up, so I was wrenching under his tutelage at a very young age. I can remember him sometimes saying something like, if it's working good it just won't like being "disturbed?"

It sounded kind of silly to a kid that something mechanical being removed and replaced would then give trouble, but I've learned over the years that it does sometimes happen.

Oh well, it could be worse, after having the dash off it could be that you have to go back for an evaporator.....

Keep us posted on the cooling progress. This is turning into one of those threads that could be valuable to someone in the future when going through the archives.

Hang tough, you'll get it sorted out.

jcyuhn · #70 07-24-2012, 10:30 AM

Quote:

Originally Posted by ps2cho

You know what...it was only doing the noise on low speed. Just a coincidence it happened the day after the dash removal?

I removed the blower assembly about a month ago to check/clean the evaporator (which was clean) so maybe the first time its moved in 24 years wasn't a happy thing?

Sounds like a typical 124 blower at that age. I'm guessing it's nothing you did during work on the car. More likely it just never used to slow down to a low enough speed that the noise was audible. My '93 was making this kind of noise for a good long while before selling it last year, so I don't think it's indicative of impending failure. Live with it until you get around to lubricating the fan bushings.

JamesDean · #71 07-24-2012, 01:51 PM

My 190E had something similar happen to it with regard to the blower fan.

Over time I lost I/II and to some extent III because of the fan's age and state of bearings. It got to the point where it sounded like a prop plane!

Replaced the motor, swapped the squirrel cages over to the new one and all was good!

ps2cho · #72 07-24-2012, 09:13 PM

Everything has been cooling so much better and the cabin is definitely nicer to be in. I think as soon as I put the bigger compressor and R12, its going to put icing on the cake.

I would say the biggest difference is idle. At least now it doesn't shoot up 10F within 30seconds at idle like it used to. I'm very happy with the outcome.

The noise hasn't shown up in the last 2 days, so maybe its gone, who knows. I can live with it since when the fan is needed on low, I can probably just have it run a little higher and it'll stop.

With the new later model dash:

Air&Road · #73 07-25-2012, 08:36 AM

Wow! Looks great!

The R12 reverse conversion sounds worth while, but I REALLY don't think you will buy much with the higher volume compressor.

What is the latest on your vent temps?

JamesDean · #74 07-25-2012, 09:01 AM

Does the 10P17C bolt up in place of the 10P15C? I think my 190 might eventually be in need of a replacement whenever I get to re-doing the a/c. I currently dont have much in the way of at idle a/c. When the compressor is above 1500-2000 I have wonderful cooling.

That might be just a charge issue but I'm not sure. It took a bit of refrigerant to get the system to have 165Psi high side when I added stuff a few weeks ago.

jcyuhn · #75 07-25-2012, 10:35 AM

Quote:

Originally Posted by Air&Road

Wow! Looks great!

The R12 reverse conversion sounds worth while, but I REALLY don't think you will buy much with the higher volume compressor.

What is the latest on your vent temps?

I think the 17 compressor buys you better cooling at idle because the low side pressure doesn't rise so much. But there is no benefit once moving, at road RPM the 15 provides all the refrigerant the evap can handle. The 17 would be nicer, but I personally would not invest the time or money for that degree of improvement.