Please help! AC low pressure port?
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Joined: Aug 2021
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ML 320CDI
A/C low pressure port
Hi,the low pressure port is no.1 on your engine pic.The high and low are different sizes so you should not be able to connect to the wrong one.The low pressure is smaller but on the larger pipe.Hope this helps
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Joined: Apr 2019
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From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
The low pressure side is the return line between the cabin evap and the gas compressor upfront near the drive belt.
Everywhere around here you can read that it's a good idea NOT to overcharge your A/C system as this will reduce the cooling efficiency.
You will cool better undercharged than overcharged specially in hot weather when pressures are at their highest.
If you have a leak... find it with a UV die or a snifing tool.
Everywhere around here you can read that it's a good idea NOT to overcharge your A/C system as this will reduce the cooling efficiency.
You will cool better undercharged than overcharged specially in hot weather when pressures are at their highest.
If you have a leak... find it with a UV die or a snifing tool.
Last edited by CaliBenzDriver; Aug 23, 2021 at 07:19 PM.
Out Of Control!!
Joined: Apr 2019
Posts: 11,727
Likes: 6,670
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
free quicky
The amazing shredder valves in Hi/Lo ports have a tendency not to sit well under extreme pressure. They can easily leak pressure.
> Test:
put some spit over the valve opening and observe for bubbles : leak/no leak?
> Fix:
1-- Push down the shredder valve plunger a tiny amount and let it re-sit itself. (Wear glasses - Beware of frost injury).
2-- If gentle does not do it, repeat re-sit procedure pushing down/letting go differently each time.
This should not loose a significant amount of refrigerant.
In the end if it doesn't work then get two new valves installed at once both hi/lo.
Even new valves can leak if not sited well. Try the spit-test.
Thread Starter
Member
Joined: Dec 2020
Posts: 163
Likes: 54
From: A small city
2010 W212 E350
> 5mn fix... no parts:
The amazing shredder valves in Hi/Lo ports have a tendency not to sit well under extreme pressure. They can easily leak pressure.
> Test:
put some spit over the valve opening and observe for bubbles : leak/no leak?
> Fix:
1-- Push down the shredder valve plunger a tiny amount and let it re-sit itself. (Wear glasses - Beware of frost injury).
2-- If gentle does not do it, repeat re-sit procedure pushing down/letting go differently each time.
This should not loose a significant amount of refrigerant.
In the end if it doesn't work then get two new valves installed at once both hi/lo.
Even new valves can leak if not sited well. Try the spit-test.
The amazing shredder valves in Hi/Lo ports have a tendency not to sit well under extreme pressure. They can easily leak pressure.
> Test:
put some spit over the valve opening and observe for bubbles : leak/no leak?
> Fix:
1-- Push down the shredder valve plunger a tiny amount and let it re-sit itself. (Wear glasses - Beware of frost injury).
2-- If gentle does not do it, repeat re-sit procedure pushing down/letting go differently each time.
This should not loose a significant amount of refrigerant.
In the end if it doesn't work then get two new valves installed at once both hi/lo.
Even new valves can leak if not sited well. Try the spit-test.
Last edited by My W212; Feb 18, 2023 at 10:37 PM.
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Joined: May 2018
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From: Jakarta-Indonesia
2014 - W212.065 - E400 ( M276.820, 3 liter Turbo) RWD not Hybrid
Is that UV dye in the refrigerant part of MB original refrigerant fill or all R134a has UV dye in it from refrigerant manufacturer ?
Thread Starter
Member
Joined: Dec 2020
Posts: 163
Likes: 54
From: A small city
2010 W212 E350
The application is very similar to what MB suggests.....
