|
|
|
|
|
#1
07-24-2009, 11:43 PM
|
|||
|
|||
|
91 350sdl A/C problem Need your help
Hi, Im a tech at an auto repair shop in Texas and im working on 91 350SDL. It came to me with an a/c problem of hi side pressure too hi. I found that one fan was not working so I replace both. Pressures didnt go down so I replaced the compressor, dryer, expansion valve and evap core. I flushed the condensor and all the hoses all looked fine. Pressure still climbed! So I replaced the condensor. Let me also note that this veh. has been retrofitted to r134 prior to coming to me. Pressures still climb!!! I decided to replace the expansion valve again and the pressure still climbs to the point of turning off the compressor. Ive tried freeze 12 with no luck. Another note the fans never run at hi speed, I thought that might be it so I bypassed the relay and jumped them to the battery. Still no luck. Help!!!!! The only thing I can think of now is to replace the hoses, but I dont want to keep throwing pasts at this thing.
PLEASE PLEASE HELP ME!!! 
|
|
#2
07-25-2009, 12:38 AM
|
||||
|
||||
|
did you double check that you have the proper amount of freon in it? also, when retrofitting over to 134a the original capacity is not the right amount. also, are there filters in the a/c lines?
__________________
have no worries.....President Obama swears "If you like your gun, you can keep it 
|
|
#3
07-25-2009, 02:06 AM
|
|||
|
|||
|
We are used to the R4 Delco... but on that late a model I am not sure what type compressor you have ...
Tell us what the pressures are. When you check the pressures are you at high idle AND with a good shop fan blowing across the condensor ? Preferably a squirrel cage type.... ? Is the AC set on MAX ? You ' tried freeze 12' ? So what refrigerant do you have in it NOW ? Have you flushed the entire system at one time during all the replacement of parts ?
__________________
1980 240d , chain elongation, cam marks reference: http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html evap fin cleaning: http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator A/C thread http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html
|
|
#4
07-25-2009, 03:30 AM
|
||||
|
||||
|
wiring posibility
the compressor should be the nippon denso,
but make certain the fans are turning in the proper direction (draw air from outside to engine), i have seen some new units that have the motor windings wired incorectly. the actual wiring at the plug will be colored correctly. they will turn in the opposite direction and will not allow pressures to drop. try reversing the leads at the connector.
__________________
1967 250 S 1967 280SE 1968 250S 1971 280 SE 1973 220 1974 280 S 1975 450 SEL 1976 220 D 1979 300SD 1983 300 SD 1985 230 TE euro 1986 280SL 1986 500 SEL euro 1986 190E 2.3 1990 300 SE 2003 C230 K 2004 C230 K 1987 560SEL 1987 300SDL now in canada 2005 C230 1998 C43 AMG Sold to DON 1993 190E 2.6 300TD Former daily driver Totaled current: R320 CDI Ram 2500 Cummins Last edited by Carson357; 07-25-2009 at 03:36 AM.
|
 |
| Bookmarks |
|
|
Linear Mode
