C32 AMG, C55 AMG (W203) 2001 - 2007

Coolant loss C32

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Old Nov 24, 2015 | 08:42 AM
  #1  
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C32 AMG, E55 AMG, CLS550, G55 AMG, C43 AMG
Coolant loss C32

Hey guys/girls,

I've had my C32 for a little while but I'm a new member. I'm losing coolant on my C32 and I can't figure out where it's leaking. I have the needswings coolant isolation kit and my coolant overfill tank loses coolant at a steady rate. I have to top off about once every 2 weeks or so. There are no visible leaks. If it's leaking from the overfill tank and I have the systems isolation kit installed, then it can't be leaking from the S/C side correct? I have a new BEHR radiator so I don't think it's gycol in the tranny. If I leaked that much into the tranny, I'm sure my tranny would be dead by now. I had my coolant tested for exhaust gas in case I had a head gasket leak but it's also not that. I also replaced the coolant tank cap 2 times, so I don't think it's that either. Any other suggestions?

thx

- JW
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Old Nov 24, 2015 | 10:17 AM
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2003 C32 AMG, 2012 C63
Could be your intercooler
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Old Nov 24, 2015 | 10:38 AM
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Isn't the I/C on the S/C side? The cooling systems are separated by the isolation kit. I'm losing coolant from the overfill tank which doesn't go to the S/C side.
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Old Nov 24, 2015 | 01:01 PM
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No spots on the ground? When parked.
Make sure the iso kit not leaking from the 2 shut off valves, turn Iso valve open to see if it still leaks, it could be clamp
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Old Nov 24, 2015 | 01:33 PM
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No visible leaks. All the hoses are up front. There are no leaks from the valves for sure. No coolant on the floor or under tray.
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Old Nov 24, 2015 | 06:20 PM
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Originally Posted by cuz_im_yellow
No visible leaks. All the hoses are up front. There are no leaks from the valves for sure. No coolant on the floor or under tray.
I would suspect intercooler. Only way to check is to remove airboxes, and pull off one of the intake manifolds. It's easy to do but make sure not to damage the gaskets when you do it or you'll need new ones. If there is brown/green gunk inside your intercooler is leaking. I have one to sell that I never used that's thermal coated by Needswings if you do end up needing one. Pressure tested and ready to go. Let me know.
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Old Nov 25, 2015 | 08:00 AM
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As I mentioned above, doesn't the I/C isolation kit separate the Intercooler system from the overfill tank? Therefore if I'm missing coolant from the overfill doesn't that mean it's not related to the IC?

thanks
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Old Nov 25, 2015 | 09:07 AM
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Sorry, missed that.

OK then it's one a few things

1. The isolation valves are still open and it's your intercooler
2. There was air in the system after the isolation kit install and it's working itself out
3. Your heater core is leaking but you'd have some nasty smells in the cabin and a damp floor.
4. Your head gasket is going.........check your coolant to see if there is any oil residue and check your exhaust tips........any strange smoke?

how much have you added since this all started?
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Old Nov 25, 2015 | 10:46 AM
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Dasauto said it all there
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Old Nov 25, 2015 | 01:30 PM
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Originally Posted by Dasauto
Sorry, missed that.

OK then it's one a few things

1. The isolation valves are still open and it's your intercooler
2. There was air in the system after the isolation kit install and it's working itself out
3. Your heater core is leaking but you'd have some nasty smells in the cabin and a damp floor.
4. Your head gasket is going.........check your coolant to see if there is any oil residue and check your exhaust tips........any strange smoke?

how much have you added since this all started?
1. Both valves are closed. Though I cannot pressure test them to make sure they are sealing 100%, they are both indeed in the closed position.

2. I've had this leaking issue for months now, so I think any air in the system would have been bled out by now. I did consider this which is why I waited months before I posted this in case this was the issue.

3. I've been using the heat for 2-3 months now, no smells or wet carpet. Also something I considered but I don't have any of the failed heater core symptoms.

4. This is the only thing I could think of as being the culprit although I've had a mechanic check for presence of exhaust gas and oil in the cooling system. Came back negative.

I've also checked all lines coming in and out of the rad and all lines in the coolant isolation kit. There are no leaks anywhere. I'm baffled. I have to top off about half a cup full every 2 weeks.

What I'm going to do is open the valves up today and run the system through non isolated. At least if it is indeed the IC leaking I would be able to tell if the overfill tank level decreases significantly. If not, then it's definitely not related to anything on the S/C side.

thanks

Last edited by cuz_im_yellow; Nov 25, 2015 at 01:33 PM.
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Old Nov 25, 2015 | 02:06 PM
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If u do have oil dip stick look at it to see the colour, or even the oil cap.
Head gasket?
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Old Dec 28, 2015 | 04:17 PM
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had the same issue nothing showed when tested but once stripped down it was the headgasket
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