Maybe, maybe not. The cap is supposed to keep it slightly pressurized, but if you've got a known leak, then perhaps you also have a cracked head or leaking head gasket.
My theory on why OM603 cracked heads keep the system pressurized: exhaust gas under high pressure gets dissolved into the coolant. Think seltzer water. Your can buy a test kit at Napa / FLAPS for testing the coolant for presence of exhaust by-products, make sure to get one specifically for diesel engines. You can also send an oil sample for lab analysis to see if coolant is mixing into the oil. -- Max Dillon Charleston SC '87 300TD '95 E300 On February 14, 2015 10:59:05 AM EST, dseretakis--- via Mercedes <mercedes@okiebenz.com> wrote: I went to add >some coolant and noticed a few bubbles of coolant emanating from the >tstat housing cover around where o ring seals. Now the car was sitting >overnight in negative temps when I noticed that. The upper rad hose was >soft but when I removed rad cap the system was slightly pressurized. Is >that normal? Should there be any pressure left after sitting overnight >in the cold? > _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com All posts are the result of individual contributors and as such, those individuals are responsible for the content of the post. The list owner has no control over the content of the messages of each contributor.
