A/C expainsion valve hoses leaking - PeachParts Mercedes-Benz Forum

latitude500 · #1 05-21-2011, 12:40 AM

So I finally had my A/C worked on today and they ran a dye through the system and the tech stated that both hoses going into the expansion valve are leaking. I couldn't find a diagram of my A/C system and the search button didn't help much.

He stated that it's under the dash and I should find someone that knows more about MB to work on the system. So is these something I can do to replace both those hoses. Where does the item live on my car? Or should I take it to someone that has all the right equipment?

Thanks for your help

leathermang · #2 05-21-2011, 01:07 AM

Very Strange.... if he actually used dye to find the leak... he should have been able to take a picture of it... point it out to you exactly where it is exiting the system......
What I suspect is he put dye in but used a sniffer to find the leak...
But in that case how did he know Both hoses were leaking ?
I do not have manuals for your car... sorry...

vstech · #3 05-21-2011, 09:46 AM

technically, there is only one hose GOING to the expansion valve on a refrigeration system. I wonder what "both" means... there could be another hose exiting the expansion valve, but usually, it's mounted to the evaporator. pics would be nice.
anybody got a fsm shot of the txv?

leathermang · #4 05-21-2011, 11:57 AM

The guy was probably including the exhaust tube from the evaporator...
another reason to take him at his word and find someone else to do anything else to the system....LOL

latitude500 · #5 05-24-2011, 02:01 PM

Thank you all for your help.

I wanted to update the post for future readers that might have had this issue.

The expansion valve is located 4-5 inches above the gas peddle and is a small silver box with 4 hoses going into it. The top copper hoses are the ones to be supper careful with. If you damage them your A/C system is dead for ever.

I totally understand why the shop didn't want to do the job. The bottom hoses are the high side and low side I believe of the A/C system. You have to remove the small blue hose first, then the large black hose last. You also need someone to hold the expansion valve so it doesn't move around. Believe it or not it's not held on by anything but the hoses. Very bad design over all.

I was able to get both hoses off the car and have them rebuilt at a A/C shop for about $180.00. However again, grate care should be taking when removing the hoses because if you damage the expansion valve cooper hoses I don't know if there is a way to repair them with out taking out the complete unit.

Hope this helps.

AMH · #6 05-26-2011, 09:00 AM

Quote:

Originally Posted by latitude500

Thank you all for your help.

I wanted to update the post for future readers that might have had this issue.

The expansion valve is located 4-5 inches above the gas peddle and is a small silver box with 4 hoses going into it. The top copper hoses are the ones to be supper careful with. If you damage them your A/C system is dead for ever.

I totally understand why the shop didn't want to do the job. The bottom hoses are the high side and low side I believe of the A/C system. You have to remove the small blue hose first, then the large black hose last. You also need someone to hold the expansion valve so it doesn't move around. Believe it or not it's not held on by anything but the hoses. Very bad design over all.

I was able to get both hoses off the car and have them rebuilt at a A/C shop for about $180.00. However again, grate care should be taking when removing the hoses because if you damage the expansion valve cooper hoses I don't know if there is a way to repair them with out taking out the complete unit.

Hope this helps.

Did you go ahead and remove the expansion block to replace all four "O" rings?
I made the mistake once of installing an expansion block backwards, it's very easy to do. As soon as the system was pressurized, the tell-tale sign was a strong hissing from the expansion block.
If the copper lines from the evaporator core are damaged, it's time to change out the core.

pop & blow · #7 05-26-2011, 03:22 PM

it,s under the dash and connects to the evaporator, get yourself a manual, expansion valves are cheap,

latitude500 · #8 05-26-2011, 03:48 PM

When I removed the hoses I didn't see any "O rings" It was very surprising. I even ended up looking for them with a flashlight and wire hook. Where can I find this magical O rings you are speaking of?

I'm deciding to leave the expansion valve in place, because those cooper hoses look scary, and I fear the idea of them becoming damaged.

lorainfurniture · #9 05-26-2011, 03:55 PM

Here is the write up that I used to change my expansion valve. With a couple of special tools is doable, just a real PIA.
http://www.funnyyouasked.com/Mercedes/W126/ExpValve/removal_and_replacement_of_expan.htm

latitude500 · #10 06-09-2011, 11:33 AM

Just wanted to thank everyone for the help. It's so nice driving around with the windows rolled up and enjoying that A/C when the dash temp gauge states 101 outside.

SO HAPPY, I love this car.