![]() |
1988 300TE AC Problem
I have a 300TE. You start the car and the AC Clutch engages, the suction line gets cold and blows cold air. Ambient pressure on the suction side 88#. As soon as the system runs I get 55# Low side and 225# High side at 90F ambient temp. The AC runs a couple minutes. Then the front electric fan kicks on. Runs another minute or so and the AC clutch kicks out and the electric fan starts. Will not cycle on again. Stop engine, restart and the whole thing repeats.
So I read and got the suggestion it was the serpentine belt. It was indeed in piss poor shape. It's a good thing i looked at it before it left the car stranded. Replaced it. No change in the behavior. Where are the usual Gremlins at that cause this? Thanx for any help! It's hot down here in S. Florida! Les |
Quote:
What do the pressures do after the fan comes on? Does it drop below 30 or so? |
Does the '88 use a compressor speed sensor? If so, a low speed reading from the compressor will cause these symptoms.
The speed could be low because of a dirty sensor, or a slipping belt or clutch. |
Quote:
|
Quote:
|
Quote:
|
What does the low-side pressure have to do with anything?
|
Quote:
|
Quote:
|
Quote:
I'll be the first to admit, I know little about MB's, but I've spent 15 years wrenching on every other make, along with handling stationary, residential, commercial & "other" systems. You could absolutely be correct - but having a low pressure switch on the high side seems silly, especially since a leak on the suction side could easily not trip a low-side switch placed on the high side because the compressor could still pump atmospheric air above 30 psi. |
Hi,
The Low side was 55 and the high side was 250. The Fan came on and the Low side stayed 55 and the High side went to 225. |
Quote:
|
Quote:
If you do, look for anything that may cause slipping. Oil on the belt or clutch would do it, and a worn clutch might. Water on the belt too, but that would only occur when it rains. |
Quote:
|
Yes, your car indeed has the speed sensor. You did not say how many miles are on the car, and you choose not to fill out your profile so I don't know if you are in a climate that heavily uses your a/c system.
IF you have lots of miles on the car in a hot climate, and the belt tensioner is holding the belt snug, then you are looking at one of two or a combination of the two issues: Either the clutch on the compressor is worn with too much air gap and/or the compressor is worn allowing excessive thrust which causes the speed sensor not to read as it should at all times. If the belt tensioner is in good shape and properly adjusted, then a replacement compressor is probably the best cure. |
All times are GMT -4. The time now is 07:07 AM. |
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website