Mb coolant questions and nightmares - PeachParts Mercedes-Benz Forum

1977busman · #1 09-29-2011, 10:41 PM

Well today my greatest nightmare came to life. The low coolant light came on in my om603 car that still has the #14 head!! Ive never hit the hazards and whiped over to the side of the road so fast in my life

I'm going to not sleep for a few days until I get this all figured out. When looking in the expansion tank I could hardly see any coolant, but there was a tiny bit in there. Well I called Roy to see what coolant I needed to get for the car and he suggested adding water until I could find the correct MB fluid for the car.(all auto zone has these day is the sketchy "mix with any" stuff) so here is my question:

-the Mercedes dealership says they only carry one type of coolant but didnt say what it was, is this going to be the right stuff? I'm assuming it's what they put in all the new stuff...
I know I'm looking for g-05 based on what Roy told me.
Ps. I really am great full that I have this forum to turn to when I am in need of help. (thanks Roy)

Additional info:
The car has never ran above 80c unless the ambient temps are in the 90's and the ac is on in traffic at which point the needle rises just a bit above 80c but is still touching it...

I'm going to do a pressure check on the system once I have new coolant to see where the leaks are if there are any.

I plan on doing a complete flush just for my piece of mind.

scottmcphee · #2 09-29-2011, 10:51 PM

Don't freak out yet, maybe you were just low on coolant ...after a summer of expansion tank spill over to the overflow tank, which spills on to the ground. Or maybe a simple leak.

pawoSD · #3 09-29-2011, 11:41 PM

Napa carries it, its called Zerex G-05, comes pre-mixed 50/50 with water or as 100% that you need to mix.

Could be you just have a leaking hose or something, I'd check all those things before blaming a cracked head right away.

1977busman · #4 09-30-2011, 07:39 AM

Thanks for the info, I'm headed to Napa here soon. And I'm thinking its just a small leak somewhere, because I have none of the usual symptoms of head issues, and the level has not really changed now that I added water. I was just initially freaked because it's usually not good when there is any coolant issues with this head.

I'm ordering a new expansion tank as well because mine has yellowed with age and I cant see through it. So I'm just going to do a complete flush and change, and pressurize the system to check for leak/.

Junkman · #5 09-30-2011, 08:06 AM

Does the 603 have a block drain plug? If so, drain the block or significant amounts of old coolant will remain. Lots of engine specific info in the archives.

compu_85 · #6 09-30-2011, 08:23 AM

There's a block drain and a radiator drain.

-J

scottmcphee · #7 09-30-2011, 10:02 AM

Block drain is below the exhaust manifold. You put a cut hose on the end of it, then open the nut, so you can direct coolant into a bucket.

After draining, I fill and flush with hose water and then fill with straight water and run the system for a bit by going on a short drive to warm everything up watching the temp gauge like a hawk... get it up to 80 or wherever your normal is. Then park for five minutes, engine off to heat soak things evenly. Then drive a little more back to your garage. Heater is turned on to defrost / hot so the core flushes too. Do not stray far from home, you don't want to get into overheat situation, like just go around block or up and down the street.

Then I drain again, just how ever much comes out the rad drain cock not the block this time, and after top up with 100% (unmixed) coolant. This blends with whatever water is left in the system. Fill through the heater hose take-off at the head (high point), with the expansion tank lid off to vent air. Drive around with the heater on still, checking reservoir frequently for lowness, topping up with either water or coolant as the antifreeze tester indicates high or low concentration. Keep checking level over a period of a few days... until things stabilize.

vstech · #8 09-30-2011, 12:04 PM

aack!!! no... after you are finished flushing the coolant and clearing the mess, you need to drain the block again, along with the radiator and the heater core, then fill with the correct mix of DISTILLED water and coolant for your area.
if it does not get below -15°F you can do a 40% coolant 60% water. 50/50 is just for REALLY cold areas.
but ALWAYS use DISTILLED water!!!
your radiator and block do not need to deal with the chemicals and stuff in tap water...
http://www.valvoline.com/pdf/zerexg05.pdf

for Ohio, I'd stick with 50/50

isnats · #9 09-30-2011, 02:04 PM

just wondering if you noticed if the electric cooling fans came on?this is very similar to the situation i am having with my 1990 350 sdl,the limo.

LandYaghtLover · #10 09-30-2011, 02:09 PM

Quote:

Originally Posted by vstech

....
but ALWAYS use DISTILLED water!!!

True that. I read my manual the other day and it said tap water was fine. Really? I think not! But there is was in the manual. I would never though.

compu_85 · #11 09-30-2011, 02:11 PM

It's important to use water that doesn't have a ton of minerals in it. How clean is your tap water? Not sure? Going to have it tested? By using distilled you don't have to worry about it

TheDon · #12 09-30-2011, 02:20 PM

Quote:

Originally Posted by pawoSD

Napa carries it, its called Zerex G-05, comes pre-mixed 50/50 with water or as 100% that you need to mix.

Could be you just have a leaking hose or something, I'd check all those things before blaming a cracked head right away.

never buy pre-mix crap unless its an emergency.

My mechanic says the expansion tank sender is known to fail and cause issues of showing a false low level. My SDL would do that to me and when it happened I pulled over and was confused why it would say low level when it was filled properly.

1977busman · #13 09-30-2011, 05:10 PM

I bought full concentrate zerex g-05, and still need to go buy some distilled water. I am going to do a full flush and drain from the block drian each time.

Quote:

just wondering if you noticed if the electric cooling fans came on?this is very similar to the situation i am having with my 1990 350 sdl,the limo

The temp never rose above 80c, and when I got out the fans were not on high.

Quote:

My mechanic says the expansion tank sender is known to fail and cause issues of showing a false low level. My SDL would do that to me and when it happened I pulled over and was confused why it would say low level when it was filled properly.

It was definetely low... I could barley see anything in the expansion tank.

Thanks for all the support so far, Ill probably do this all next week as I need to get the expansion tank ordered still.