Left side vents warmer that right side (1996 E300D) - PeachParts Mercedes-Benz Forum

Pweber · #1 06-24-2007, 10:43 PM

As it has gotten warmer I now notice my right side vents are nice and cold and left side are warmer. Any common item that causes this?

TMAllison · #2 06-24-2007, 10:57 PM

Oftentimes a sign of low referigerant.

Pull your actual values from the CCU.

Start car, run up to operating temp with ac on. Press "rest" and hold for 5 seconds. Use right auto button to toggle through the first 8 values and post.

Second pull error codes. Engine off, within 20 secs do the following: key to pos 2, left side temp to HI, right side temp to LO, press had hold rest and ec for 5 secs. Use right auto button to toggle through error codes. FF means the last one. Post error (eg: EB1 234)

Pweber · #3 06-25-2007, 02:50 PM

Even on the econo setting ( no AC comp. running) the drivers side air is warm where the pass. side is normal outside temp. This tells me the mix door for the drivers side is not shut. Or, I notice there are 2 solenoid type valves under the hood by the ECU. They appear to be in line with the coolant hose. Do these shut hot coolant flow off the the heater core/ cores? If so could the driver's side not be shutting off?

e300D97 · #4 06-25-2007, 03:05 PM

Yes thats called the DUO Valve and probably your culprit, although the temp sensor for the driver side could be at fault also. I would pull out the Duo Valve, clean it and see if that makes a difference.

Pweber · #5 06-25-2007, 03:44 PM

I will check it tonight. I just found some threads on that very topic. Seem common.

Pweber · #6 06-26-2007, 11:06 PM

TMallison,

Here are the first 8 values. 1- 25, 2=28, 3=28, 4=21, 5=27, 6=93, 7=04, 8=18

As far as codes it had these two: EB1 462 & EB1 234

Matt L · #7 07-03-2007, 11:59 AM

Quote:

Originally Posted by Pweber

I added a can of R-134 last weekend mine still blows way hot on driver's side and the coolest on pass. is 60 degrees. I did notice however that compared to my VW Jetta, son's Mante Carloe, My F350, etc. the high side pres. was getting very high (275 PSI'ish and ambient temp was 86 degrees outside) I also have not ever noticed a hiss from teh center vents folks talk about. 1 question I had was: can I unplug power to the coolant circulation motor that is down from the duovalve and emulate plugging the hot coolant hose to the duovalve or do I need to block the hose completely? And if block this hose will it hurt anything for a test?

When you read 275psi, did #7 still show 4 bar? That indicates a problem. #8 showing 18C means that hot refrigerant is not reaching the receiver.

Unplugging the motor will result in a lesser flow of coolant, but will not stop it completely. MB-DOC's suggestion of clamping the hose is a good one; a pair of locking pliers with rags to soften the jaws would work for this.

Matt L · #8 07-03-2007, 12:03 PM

This may help with the pressure readings. You should show about 270psi at 80% humidity and 38C (about 100F) ambient.

Pweber · #9 07-03-2007, 01:02 PM

I tired pinching off the coolant line with a needle nose vise grip with fuel line on the jaws. Please note I can start the car from sitting 24 hrs. and within the time it takes for the pass. side to get the coolest (60-120 secs) the driver's side will be warm. Can coolant be warm enough at that point just idling to have a profound effect that soon on the driver's side?

Pweber · #10 07-03-2007, 06:50 PM

OK, have an update as of 15 mins ago. I hooked the gauges back up. It is 94 degrees out. Started car at idle and had AC on, temps on climate control down to 57, fan on high. I note I get no AUX cooling fans in font of condenser with AC on. Most cars turn the fans on at any temp with AC on. Is that what I should expect on a 1996 E300D? Anyhow, after letting thing run a bit and cool air start coming out vents. (though driver’s side is much warmer) I look at gauges. Low side is around 35, high side gauge reads around 375! I take note from what I have been reading and touch lines. High side line coming out of comp. is HOT, Condenser is HOT, line from condenser to dryer is HOT, bottom of dryer is HOT, top of dryer and output line from dryer is not hot at all. Value # 7 is very low (06) but high pressure port which is in condenser is 375? Should I assume a restricted dryer? Should the dryer and line exiting the dryer toward evaporator also be hot?

gmercoleza · #11 07-03-2007, 06:54 PM

Your aux fan should come on well before 375! You are going to damage your compressor running it like that. Jumper the high pressure switch on the receiver drier and see if it comes on. If not, unplug the aux fan and apply 12 volts to it, see if it engages. If it does, then the problem lies somewhere in the circuitry.

gmercoleza · #12 07-03-2007, 06:55 PM

BTW - the hot components are all normal, at least for a system where the aux fan is not working. I suspect once you get the fan working then everything else will fall in line.

gmercoleza · #13 07-03-2007, 06:56 PM

Quote:

Originally Posted by Pweber

Can coolant be warm enough at that point just idling to have a profound effect that soon on the driver's side?

I don't think so.

gmercoleza · #14 07-03-2007, 06:58 PM

Also, there is a pressure relief valve on top of the R/D - can you check that valve as well as the sheet metal in that vicinity to see if there is an oily residue? When the pressures get high enough, refrigerant will spew from this check valve and then - guess what? The next time you drive the car the refrigerant is now low.

Pweber · #15 07-03-2007, 09:29 PM

Question. I only get like 07 bar on the climate control diagnostic readout for item #7. I have been told that is the high side pressure. Wonder why that reads so low when the gauage shows 300 plus at the condenser? Do you know where this sensor is that gets that pressure reading for the diagnositic readout via the climate control?

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