CLK55 AMG, CLK63 AMG (W208, W209) 2000 - 2010 (Two Generations)

2001 CLK55 AMG - Severe coolant leak

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Old Jul 7, 2016 | 02:02 PM
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W208 2001 CLK55 AMG
2001 CLK55 AMG - Severe coolant leak

I recently got back from driving across the country (about 18 hours). I let my car sit for a day, then took it to work. When I got to work, I had a "low coolant" warning and found the reservoir almost depleted.

I topped off the reservoir and ran the car. The leak appears to be coming from the oil cooler or somewhere below/behind it. Whatever it is, it's getting on the belt and flinging coolant all over the place.

Can the oil cooler leak coolant? Is there something else in that general area that would do that?
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Old Jul 8, 2016 | 12:55 AM
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The upper radiator hose is right there.
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Old Jul 8, 2016 | 09:20 AM
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W208 2001 CLK55 AMG
Originally Posted by MarcusF
The upper radiator hose is right there.
Already checked it, it's completely dry.
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Old Jul 8, 2016 | 03:13 PM
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I had the two seals inside the oil cooler leaking.

http://www.benzworld.org/forums/w163...il-cooler.html


Another possibility; I had a crack in the plastic part of the radiator that only showed when under pressure.
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Old Jul 8, 2016 | 03:22 PM
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W208 2001 CLK55 AMG
Originally Posted by sick430
I had the two seals inside the oil cooler leaking.

http://www.benzworld.org/forums/w163...il-cooler.html


Another possibility; I had a crack in the plastic part of the radiator that only showed when under pressure.
I actually just replaced the original radiator because of a hairline crack, I'm positive it's not leaking. I'm going to take a closer look at it later today and see if I can definitively say it's the oil cooler.

I guess my question was a little too vague, I was just wondering if the oil cooler leaking coolant was a common thing.
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Old Jul 11, 2016 | 12:49 AM
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Originally Posted by rjalaskan
I actually just replaced the original radiator because of a hairline crack, I'm positive it's not leaking. I'm going to take a closer look at it later today and see if I can definitively say it's the oil cooler.

I guess my question was a little too vague, I was just wondering if the oil cooler leaking coolant was a common thing.
Yes, as these cars age the rubber dries and it leaks from the bottom of the cooler.
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Old Jul 11, 2016 | 01:15 AM
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W208 2000 Clk 320 cabriolet
Hey I have a w208 made in 1999 it's a 2000 cabriolet 320. With 154000 miles. I am not sure about the radiator if it's Valero the one that is known to fail and leak coolant into the transmission.
Ive change and flush coolant and it seems to be working fine. the car hasn't had any engine issues for two years now.

sick430 says that the rubber tends to wear out and I am just trying to Not get get caught off here.
Should I be thinking of replacing the radiator since I dont know of it is the original?

My Carfax says it has been serviced at Mercedes dealer until about 75 or 90 k miles or so..
+
Oil cooler and radiator are two separate parts?

Last edited by Nw208clk32; Jul 11, 2016 at 01:22 AM.
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Old Jul 11, 2016 | 07:57 PM
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Originally Posted by Nw208clk32
Hey I have a w208 made in 1999 it's a 2000 cabriolet 320. With 154000 miles. I am not sure about the radiator if it's Valero the one that is known to fail and leak coolant into the transmission.
Ive change and flush coolant and it seems to be working fine. the car hasn't had any engine issues for two years now.

sick430 says that the rubber tends to wear out and I am just trying to Not get get caught off here.
Should I be thinking of replacing the radiator since I dont know of it is the original?

My Carfax says it has been serviced at Mercedes dealer until about 75 or 90 k miles or so..
+
Oil cooler and radiator are two separate parts?

this is something completely different. Our cars 55's have an additional oil cooler. your radiator is most likely a Behr unit, if its not broken don't replace it.
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Old Jul 12, 2016 | 08:09 AM
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Hey I have a w208 made in 1999 it's a 2000 cabriolet 320. With 154000 miles. I am not sure about the radiator if it's Valero the one that is known to fail and leak coolant into the transmission.
Ive change and flush coolant and it seems to be working fine. the car hasn't had any engine issues for two years now.
Also Valero sells gas and Valeo make radiators.
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Old Jul 12, 2016 | 11:53 AM
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I would get the car on a set of Rino Ramp, or jack stands, take off the lower panel, and run it. Sit under the car and look for the leak. Make sure it gets up to temp and the tstat activates if the leak isn't immediately obvious.

I have replaced a cracked radiator (plastic end tank - leak was spraying all over the place after getting on the fan), upper and lower coolant hoses, and expansion tank. It doesn't leak anymore : )
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Old Jul 12, 2016 | 08:41 PM
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W208 2001 CLK55 AMG
Alright guys, I may have pinpointed the issue here. I think the power steering pump pulley chewed through the upper radiator hose. I shone a flashlight at it and at high RPMs after warming up, I can see the PS pulley getting sprayed, and the center nut looks awfully close to the hose. I'm going to rip it out and confirm.
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