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2 wheel drive W163 and W124
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79 Posts
Discussion Starter #1
Ok I've got a 1988 300E!

My indie mechanic threw out my AC and Heater Control Valve and replaced it with a switch off valve.

Closed: means the heat is on

Open: means the A/C is on

This is the line coming from the water pump to the condenser I imagine...

The coolant hose going to the top of the head has a switch off valve as well.

Someone please correct me if Im wrong... I just recently rebuilt a blown head and I want to get to the bottom of things

I have the updated AC and Heater Control Valve which I got from Pick and Pull
 

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Registered
2 wheel drive W163 and W124
Joined
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79 Posts
Discussion Starter #3
What should I do about it? Should I just leave it like it is. I've noticed on early nineties W124's they all have an updated AC and Heater Control Valve. Mine doesn't even have one!

What's the purpose of this valve if its running down the left side of the engine back to the water pump? I want my coolant getting to where it needs to be.
 

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W124 Moderator
86 190E 2.3L 16V, 2 95 320TE's, 02 S500
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12,746 Posts
I sort of feel like you have more than one question here. Yes, you should replace the mono valve your mechanic decided to eliminate. It's there for a reason. Using the handy short cut that has been installed defeats the entire operation of the automatic HVAC system.

If you are concerned that the mono valve failure had something to do with blowing a head gasket, don't be. Blown head gaskets are a well documented problem with W124's. Now that your's has been replaced, and I assume correctly, I would think you are good for 150M miles or so as long as your cooling system is always up to par.

Good Luck,

Jayare
 
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