Just did a brisk 2 hr drive over the weekend
And the next morning noticed that my upper radiator hose collapsed.
Opened the cap on the expansion tank and the hose expanded to normal.

So my question, is the cap supposed to be the same cap used for radiators?
Or should it be a different part.

I believe the one on my expansion tank is 20 bar

The epc has a part # for the expansion tank cap
But that number is unrecognized in part searches

Thoughts?

yup. same part.

if the hose is collapsed, you have a bad cap, or a plugged overflow hose.

I GUESS, you could have a bad thermostat cause the issue... if it's REALLY cold out.

__________________
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!

I've been noticing the same thing on my OM606 W124, I was suspecting it was the hose as the upper is the original with almost 200k on it! I think I'll still replace the hose, of course, but now I'll also be doing the cap as well.

ok thx.

radiator, hoses, overflow tank, thermostat are all new.

nissens radiator.

the cap is reutter.

I guess i'll try another one.

just wanted to make sure its not a different cap for the expansion tank.

Are you sure you are not overfilling the expansion tank? There needs to be some air space.

Make sure the overflow tube is clear, insects can build nests in the hose.

The parts stores have cooling system pressure testers that also will test your cap. Do that before taking a chance on a new McPartStore cap.

__________________
85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

You know that 20 bar is 290 psi, right? 61x's usually take a 1.2 bar cap and 60x's take a 1.4 bar/20 psi cap.

To expand on what vstech said, a cap can pass a pressure test but not work properly under vacuum to draw overflow coolant or air as the system cools.

Sixto
83 300SD

It might be 20lbs, or 120 centibar, but not 20 bar.

X5

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

my mistake

its stamped reutter 140

I guess I have the 1.4 bar installed since its stamped 140. and perhaps I need the 1.2 for the om617

correct?

1.4 bar systems usually have a label on the reservoir instructing such. Check the manual or someone who knows for sure like peachparts.com what pressure rating your car has.

Sixto
83 300SD