Why does me coolant bottle keep refilling on the E420?

[Ascension]

Why does the coolant bottle keep refilling on the E420?

First off the car is running cool stays right at 80C and I have never seen it run past 90C since I have owned it.
When I got it the bottle was completely full with no air space so I pulled a little out to get it back to the "stand" line. Noticed when I was under hood with the blown fuze/ no crank issue it's back completely full with no air space again like it purged out all the air somehow?? Never seen one do this before so got to ask is this normal for these???
Again no issues in cooling of any kind coolant is the green stuff looks really clean and bright and I have no loss of coolant no over heat nothing just the bottle is completely full again .

 

[Glen]

These cars have a secondary recovery tank located in the right fender well. It's probably full from previous overfilling of the cooling system. I'd start with a new radiator cap and also get rid of the green coolant. Zerex G05 is the correct stuff to use.

 

[Klink]

These cars have a secondary recovery tank located in the right fender well. It's probably full from previous overfilling of the cooling system. I'd start with a new radiator cap and also get rid of the green coolant. Zerex G05 is the correct stuff to use.

 

[gerryvz]

You can buy Zerex G-05 at any O'Reilly Auto Parts store, FYI. Get a couple of gallons, and dilute it 50-50 with distilled water you buy at the supermarket.

I always keep a gallon of coolant+water "premixed" in the garage for normal coolant evap/topping off from time to time.

 

[Ascension]

That there is a secondary tank makes absolute sense now as i was going WHAA when I saw the bottle was back full. Where is the secondary tank? I noticed the cloth sheathed line from the overflow bottle running towards the windscreen then down but never saw a tank and just assumed it dumped underneath.
With the green stuff really clean and the car running so cool for now I may leave it alone until I catch up on some other issues then go Evans waterless on this one. I do have a couple mixed gallons of GO5 (50/50 with distilled) from running it in the Volvos but am intrigued with the thoughts of the Evans stuff and getting all the pressure off the system. Have an Evans waterless dealer just a couple of miles or so from me here.
What is the pressure of the cap supposed to be? I have a cap tester so let's see where it is.

 

[gerryvz]

The secondary tank is located behind the passenger-side front fender.

Please see the linked HOW-TO below, which indicates the maintenance relating to this tank. Apologies if there's not enough detail in the post.

http://www.500eboard.com/forums/showthread.php?t=4764

Cheers,
Gerry

 

[Glen]

Cap pressure is 1.4 bar...you should see a 140 stamped on it for 140 centibar = 1.4 bar.

 

[Ascension]

The secondary tank is located behind the passenger-side front fender.

Please see the linked HOW-TO below, which indicates the maintenance relating to this tank. Apologies if there's not enough detail in the post.

http://www.500eboard.com/forums/showthread.php?t=4764

Cheers,
Gerry

Thanks never knew that tank existed so this all now makes perfect sense and it also explains why on occasion I would catch just a whiff of coolant when I first started it after an overnight as I bet it was overfilled and venting a little from the secondary tank after shut down then I was smelling it for just a second when it hit hot exhaust when it was refired. That all stopped when I pulled that pint or so of coolant out of the tank and has not returned. So should the main tank be full with this design or fill to the stand line only? it would make perfect sense for the system to naturally purge all the air from the system over time with this design.

 

[gerryvz]

The under-hood coolant expansion tank should be filled up to about the top seam.

The secondary expansion tank behind the fender usually shouldn't have much if anything in it. It's just that ... an emergency/secondary expansion tank so that the car doesn't overflow coolant onto the ground.

 

[Ascension]

The under-hood coolant expansion tank should be filled up to about the top seam.

The secondary expansion tank behind the fender usually shouldn't have much if anything in it. It's just that ... an emergency/secondary expansion tank so that the car doesn't overflow coolant onto the ground.

Some one must have over filled the heck out of it Gerry before I got it then. I pulled the level down to that "stand line" mark at the upper seam right after I bought it but I noticed when I ran the fuse issue down it's completely full again. So should I pull the level back down? It must have had enough coolant in the second tank to refill the upper bottle after running several hundred miles and going through a few cycles as it expanded and purged all the air then pulled coolant back in. Shes running dead on where it should be in temps so---.

 

[gerryvz]

I'd pull the coolant level down to the seam line again.