100 = 1 bar = 14.7 psi
120 = 1.20 bar
140 = 1.4 bar

Your 100 cap is fine, it simply means that you can't overheat the engine as much as you could with a higher pressure cap. If you have a leak in your system (cracked tank top or whatever), the lower pressure cap is better. Mercedes tended to increase cap pressure in later models: my 123 has a 120 cap while my 124 and 210 both have 140 caps.

OK, I ordered my new radiator too! I'll race you getting it in... :D

So, I should go ahead and order the proper cap too? It sounds like from what I have been reading now that it should be the 120.

Cool..... Literally!:) I guess now is better than 1 or 2 months from now when it is REALLY HOT and it rains every afternoon! I hope it goes well for you. I always get paranoid ordering anything this fragile. It seems like fins always get bent or corners get dinged. Maybe we will get lucky.

I still cannot find that fat little short hose beneath the thermostat housing. It looks pretty bad too. I guess I will wait until I have the rad out, then take it in and size it up for replacement.

Yes thats fine 100 is better than 120. It means that the cooling system has to build up 100 before it opens to allow coolant to overflow.

100 caps are hard to find, most people just use the 120.

I don't think that's right at all... 100 PSI would blow a cooling system apart. Cap pressures are in BAR as Jeremy stated and should open at the rated pressures he stated above.

Your correct. I meant to say bar instead of PSI. Sorry... I'll edit my post. Brain fart...

Thanks again for the input guys. I got the idea. Basically I should stick with cap I got and just get it tested.:D

One more question. I was reading somewhere about using Zerex in the Gold bottle? I just went to 2 different auto parts stores. Neither had it and the nearest NAPA is over 30 miles away. Is there another brand or type that I can use?

Are there going to be any surprises removing and replacing this particular radiator?

NAPA is the only place I have seen that actually has it. You could buy it at the dealer for $25 a gallon if you want.....

Rad replacement is a fairly straight forward procedure. Just remember to have a little tranny fluid on hand. Don't go muscle man on those tranny cooler lines either, just snug them down a little, if they leak then tighten them some more.

:confused:

Thinking that our injectors pop at 135 bar, I googled and it says 1 bar = 14.5037738 pounds per square inch, so 100 bar would be ~1450psi.

Edit: well, if I had bothered to actually read the whole thread I would have understood. :embarasse

And btw, I'm right there with you guys. The JB weld the PO put on mine has started to weep.

Radiator replacement is an extremely easy task, no sweat. While you are at it, check the transmission fluid cooler lines, if they're original, replace 'em as they're cheap.

You'll have to "burp" the system when you refill it but it's not hard.

Yes, you need either the MB coolant or the Zerex in the gold bottle. Not to worry if you cannot find it right now, it won't hurt anything to run plain old distilled water until you can get by the nearest NAPA.

Found this nice replacement pictorial linked off the MBCA forums:

http://benzguy.piczo.com/engineradiatorreplacement123,126?cr=7&linkvar=000044

Sweet! Thanks for the link!!

I'm headed up to Palm Bay tomorrow. I'll get the Antifreeze from Napa up there. Does anyone else carry the stuff?

the cap might be original and need of a change.


Mercedes has the coolant lol.. But its expensive. Glad Hatty gave me two gallons of the stuff.

Pierre put this particular cap on the car at the GTG. It had the wrong cap on it and the seal was shot.

I'm thinking that since the old cap was shot, when Pierre put the new one on it has been pressurizing normally for the past few days. Then the old radiator just "gave up the ghost".:rolleyes: It does look like the original radiator.