Put 3600$ in preventive issues , water pump coolant hoses upper lower radiator hoses reservoir itself , tune up power steering pump and so on also new radiator ..
the problem is , after 20 min of driving I’m loosing good amounts of coolant and smoking like a bbq pit lol oil is not milky , car never overheats no white smoke , no funny sounds only a crankshaft code and evap
(2006limited roadster)
PLEASE HELP BEFORE I LOSE MY S***

 

How long have you owned the care, what model and how many miles?

 

3 years 119,000 2006 limited roadster

 

Your description (partial) : "problem is , after 20 min of driving I’m loosing good amounts of coolant"
On a routine drive I got a low coolant light, strange because I never saw any fluid on garage floor or any other indications of a leak or problem. Topped coolant off (not a large amount) and it happened next time I drove the car, again no signs of leakage anywhere. With a lot of troubleshooting it turned out to be a simple problem. The "O" ring in the coolant cap needed to be replaced.

 

yeah the new reservoir didn’t come with a new cap just the reservoir .. so I used the old cap maybe that’s the issue ?

 

The problem only occurs after pressure buildup thus the 15 - 20 minute delay and subsequent loss of fluid while driving making it hard to detect, at least in the aforementioned "O" ring situation.

 

can u list the part ? A new cap come with “O”ring?

 

I think copperfieldkid nailed it. When the car is cool, run your finger or a towel under the cap opening and see if you have any residual coolant there, or see if it's stained with whatever color coolant you have.

 

would that be the reason for smoke ?

 

It could if the coolant is hitting the exhaust manifold. When it gets pressurized it sprays out and the fan, or air through the grille is probably blowing it back towards the engine.
Was there a lot of coolant in the engine belly pan?

 

not a lot but that’s where the drips are at when I replaced the radiator I replaced every hose to coolaint reservoir and radiator so I think u could be spot on !

 

The new cap part # is Mercedes-Benz 2105010515. (2003 Mercedes-Benz SLK 320)

 

does it come with the 0 ring thing?

 

I think it comes with the seal in it. Here's an example of one: Expansion tank cap
If you need it fast you can go to a Mercedes dealer (hopefully they will have it in stock). You will need a VIN from an SLK 320. Find one for sale and use the VIN from it.
Bring your original cap with you. They might even be available at a regular auto parts stores.

 

THANK EVERYONE WHO REPLIED Ppreciate y’all fr

 

I hope it all works out for you. Let us know.
John

 

The radiator cap looks good , O rings looks okay now what😭😭😭😭😭😭😭😭😭

 

The smoke coming from all under the front wheel well valve covers got changed 30 days ago proffessionally , I smell coolant , about 2 inches disappear after 30 min driving smoke coming from driver side ..
radiator and ALL HOSES CHANGED 2 days ago

 

How does the oil look? Is your car a manual or automatic? Have you checked the heater hoses at the back of the engine compartment - I had car where the heater hose cracked at the firewall.
-Jerry

 

oil not milky , iys good , still have 4,000 miles till next service .. will check