Curious, I was checking the car out this morning and found the upper hose sucked completely flat. I thought the cooling system was supposed to pull water back in from the tank when it cooled down... I loosened the cap and air sucked in and the hose re-formed itself.

Is there a blockage in the vent for the tank / degas bottle? Is it supposed to form a vacuum?

Thanks for the insight.

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

... low on coolant.
the tank is an expansion tank, not an overflow tank. if the hose went flat, you are low on coolant, or your cap is defective and lets out too much pressure.
also, your hose is probably weak.

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Bad cap.

__________________

Gone to the dark side

- Jeff

I have the same car, with the same problem. I changed several new caps, and the problem persists. So I don't think my problem are the caps.

My antifreeze is at the right level. I do have a very very minor leak. ie: a few drops a week. So I don't think that this is the problem either. What I did, is the same as you. I opened the radiator cap each morning over a period of about 2 weeks,and the sucked-in upper radiator hose was getting less sucked in each and every day. At the end of about two weeks, the problem was gone.

So first try the changing the cap, if that does not resolve your problem then do what I did, and you should be OK.

By the way, the service manager at the local Mercedes dealer told me that his Mercedes (not sure which model) has the same problem, and he never figured out what the cause was. He is however not concerned, nor is he trying to resolve the problem.

__________________
'95 E300 Diesel, 264,000 Miles. [Sold it]

I did get a "low coolant" warning this afternoon so I'll top it off tomorrow morning. I haven't noticed any leaks though...

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

MY 560SEc did the flat hose thing on the Nor CAl diesel Drive last time and an Indy that was there told me to replace my rad cap. I did(and replenished a bit of coolant) and that fixed it.
He also fixed my no bright lights issue by putting the two fuses in the respective places. (I didn't even notice that they were missing as I'd just had the car for a week). DUH!

I had looked at the fuse box, but didn't notice the two empty receptacles.)

__________________
1986 Euro 500SEC "RUF" 9:1CR, "Rose"
1985 Euro 500SEC Cabriolet AMG Widebody
1982 Euro 500SEL "Blue"
2001 Texas Heeler (Aussie/Queensland X) "Sulphie",
2012 Queensland Red Heeler "Squeak"
Best dogs I've ever had.

Update: Yesterday, I pulled the cap, rinsed it off and attempted to suck through it from the bottom but it seemed to be stuck. I pried it apart and soaked it in a CLR/water solution for a couple hours which removed the slight calcification deposits that were covering the check valve.

We'll see how it does today...

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250