CLK500 TWINS

Okay, anyone who followed me before knows I had a coolant leak a couple weeks after I bought the car amongst other things. Water pump was replaced with OEM and the system was flushed. Car had been fine. About a week ago it told me I needed washer fluid and when I popped the hood, I noticed the washer cap wasn't on (blown off maybe, cause it had been prior). Replenished washer fluid. Cars been sitting for two days. I take it out last night, it tells me to check coolant level and it goes away. Pop the hood and everything looks good, besides a little gunk build up on the seal between coolant reservoir and washer reservoir. Park it and nothing leaking till maybe 3-4 hours later, I noticed spots on ground. By morning, that spots a lot larger and my coolant reservoir level is showing it. Any ideas?

tusabes

Your washer fluid reservoir is heated and uses a line from the coolant to heat it
The coolant may be leaking into the washer reservoir

CLK500 TWINS

Any simple way of checking on that? If it was leaking into the washer reservoir, why would it be on the ground?

tusabes

Either the tubing between the two is leaking, or maybe coolant is filling up the washer fluid container past its top and spilling on the ground . That Could be why the washer fluid cap was blown off .

You can try to diagnose your self by completely emptying the washer fluid reservoir then running the car to see if the washer fluid tank is filling up with coolant or if you see any leaks but it may be hard to see

CLK500 TWINS

Alright, keep in mind, I don't even know how to change a tire, so I didn't pull anything apart here. I'm going to do my best to illustrate what I found and hopefully someone who better knows the schematics of what's under the hood can explain it to me.
The leak is exactly vertically aligned with where the reservoir is. I looked everywhere I could see from the under the hood with a pen light, nothing! I got down on the ground beside the passenger front tire. Looking in between the front of the tire and the wheel well, there's the shield covering the bottom of the car. There are two "clips" holding this in place that I can see, one closest to me and the second further. That second one is where the coolant is pooling and dripping from. If you look directly up from there, there is another shield covering the inner portion of the wheel well. This shield is thicker plastic and it's vented. If I look through those vents directly above where the coolant is leaking, there is what appears to be a silver metal "box." Attached to that "box" is a thin black hose which is connected with what I believe is a black rubber ring or a "gasket?" This gasket is wet and so is the first maybe half inch of the hose that it's connected to.

I know that was tough, but hopefully someone can take a look at their own and tell me what this is. Thanks in advance.

biker349

empty the wiper reservoir as described earlier. you can either pull the washer pump out of the reservoir, let it empty and refit the pump, or use a turkey baster, or something similar to withdraw fluid from the windshield wiper reservoir and see if the water level increases over time. then you'll know if the piping is leaking antifreeze into the system. you'll probably still need a mechanic to replace, or cap the pipes if that's the problem.

tusabes

Looks like you've identified where the leak is, you'll have to have a mechanic remove the under body covers and replace the leaking part if it's not a job you can do yourself

CLK500 TWINS

I wish I could do some of this work myself. I'm not certain that's where it's coming from, that's just what I could see. I did look at a diagram of the coolant system and I couldn't find a component that resembled what I saw. So I took another look and the rear left bottom portion of what I believe is one of my filters (black grated thing if you look down between what I believe is the MAF and the engine) was wet. There's a hose with a silver clamp on it right there, so idk if that's the culprit). I'm going to have to have it looked at by Mercedes if my guy can't do it tomorrow.