I think my post got lost in the mayhem.....

Thanks folks,
Keith

__________________
1983 300SD "Helga"

I'm a novice when it comes to these systems. However, I have Freeze-12 in the SD and it can handle the temperature reasonably well when the ambient temp is around 90°F. I can't swear by the vent temperature, but, I'd hazard a guess that is considerably less than 58°.

Does the temp drop with increasing rpm's? The SD doesn't do so well at idle.

Yes, your post got lost in the word war.

Answer:
Sounds like a very low refrigerant charge; have the operating pressure checked.

__________________
ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

what a kick butt website. Thanks!

__________________
1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
Mercedes How-To and Repair Pictorials
I love the smell of diesel smoke in my hair

Thanks for the tips guys.....

My temps tend to go up about 5-8 degrees when at idle...with the fan on high. The pressure seems to be OK. I have checked it with a gauge that came with the car (along with an extra can of "Johnsen's Freeze 12") and it indicates pressures in middle of the "Green Zone." The air can be finger numbing cold coming out of the vents (41 degs)....as long as the fan is on low.....but that isn't enough to cool the car on a moderately hot day. On high (and automatic), the vent temp rises and it doesn't get the interior cool enough to be comfortable....even on long trips. It is sufficient at night. My car is white, by the way....I know there have been some discussions about the relationship between the color of the car and heat buildup.

Oh, I'm just curious...what are the symptoms of an overcharge in the a/c system?

Thanks in advance,
Keith

__________________
1983 300SD "Helga"

Overcharging will have high pressure readings. Is the expansion valve new?

__________________
1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
Mercedes How-To and Repair Pictorials
I love the smell of diesel smoke in my hair

It sounds like you don't have manifold gauges. Trying to correctly charge any system, but ESPECIALLY a converted system without monitoring high and low side pressures is flying blind.

Can you borrow some gauges somewhere so that you can monitor both sides and post your pressures along with the ambient and vent temps.

Good luck,

Keep up the good work!

__________________

1988 560SL "BLTZKRG"

1992 300CE "VRIL 1"

Get a good set of guages. They are around $75 and can tell you tons of info about your system.

__________________
1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
Mercedes How-To and Repair Pictorials
I love the smell of diesel smoke in my hair

I hope this post doesn't get lost in the middle of this great conversation, but it seems like one of the best places to post.
My '82 240D has the R134 AC system and I have added freon recently.

The problem is, when I drive in town, about 20 to 30 minutes into the drive - this is with stop lights and traffic, but not stop and go rush hour traffic - the AC stops blowing cold air. It starts to lose its punch and then dies. I still get air from the fan, just nothing cold. It will actually blow hot air on a hot day. Adding freon does not fix it. If I park for 30 minutes with the engine off, it will blow cold again.

Any ideas what could cause this? I don't want to jump into re-building the whole system if it is a far simpler issue.

I believe (and will have to look it up in my records) that the AC system was worked on by a mechanic about 5 years ago. This could have been my other car though, I cannot remember off the top of my head.

Thanks for any help.

Aux cooling fan and fan clutch.
Should be your issue.

__________________
ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

You need a good set of A/C guages. Drive the car and keep the guages with you. When the A/C starts acting up hook up the guages and tell us what the high and low side read.

__________________
1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
Mercedes How-To and Repair Pictorials
I love the smell of diesel smoke in my hair

That was almost as good as the "Left behind " series.
Thanks

What was?

__________________
1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
Mercedes How-To and Repair Pictorials
I love the smell of diesel smoke in my hair