Coolant flush question - PeachParts Mercedes-Benz Forum

gorsuchmill · #1 04-29-2007, 10:13 PM

I had the dreaded green coolant and decided to replace it. I drained, flushed, degreased, flushed several more times, did the citric acid, rinsed thoroughly with water and have flushed three additional times. For each flush I've opened the block drain and pulled off the lower radiator hose. The problem is although the water looks clear when draining, it has an amber color when in the bucket. It does not feel slippery to the touch. Should I continue to flush until the water is clear in the bucket or is the amber color acceptable?

Thanks.

JimmyL · #2 04-29-2007, 10:25 PM

I think you will be fine considering the amount going back in.
BTW, where did you get your citric acid for the flush?

vstech · #3 04-29-2007, 10:51 PM

what bucket? are you draining into a bucket? is the bucket the expansion tank? did you clean the tank?
John

sokoloff · #4 04-30-2007, 08:58 AM

I'd say you've flushed enough and are good to go. I assume you turned the heater on so that all of that coolant has been flushed too.

RxDiesel · #5 04-30-2007, 09:37 AM

Quote:

Originally Posted by gorsuchmill

I had the dreaded green coolant and decided to replace it. I drained, flushed, degreased, flushed several more times, did the citric acid, rinsed thoroughly with water and have flushed three additional times. For each flush I've opened the block drain and pulled off the lower radiator hose. The problem is although the water looks clear when draining, it has an amber color when in the bucket. It does not feel slippery to the touch. Should I continue to flush until the water is clear in the bucket or is the amber color acceptable?

Thanks.

I'm familiar with the 'green' coolant issue from my Ford diesel p'up, but a newbie here - I was under the impression that the stock M-B coolant [green, need to add SCAs? Is that right?]was the way to go with M-B diesels. I'm looking to buy a 98 or 99 E300 TD - should I look to put a diesel ELC [the Cat 'red' ELC, or similar] in an M-B 606 diesel?

SD Blue · #6 04-30-2007, 10:16 AM

The MB branded, available from dealers and other sources, or Zerex G-05 are the only coolants recommended. A search will show several posts describing the reasons. They are different in the base chemical needed to protect all of the various alloys and plastics used in MB's. And for such a slight cost that is spread out over 4 yrs., it's just not worth it to chance.

gorsuchmill · #7 04-30-2007, 09:52 PM

Thanks for the input, but I'm starting to think my flushing didn't work well from the start. In an effort to improve flow through the motor I removed my thermostat, removed it's guts, then reinstalled. I performed all of the procedures with this setup and felt like I was accomplishing something. Even though I couldn't get the engine up to temperature, I didn't think it would matter with the thermostat effectively open. I had the heater at the max setting the entire time. Today, I had to take a long drive (300 mi.) in which the temp got above 80C for a good bit of the trip. When I drained the system this evening the fluid was a deep amber - almost a muddy orange. Anyway, I installed a new thermostat and will continue to flush until things clear up a bit.

I've read the thermostat needs to be "forced open" to do a proper flush. I thought I was accomplishing the same thing by taking out the innards; however, maybe doing so allows too much flow, resulting in the engine not getting up to temp and coolant not being pumped into the heater lines. Does this make sense?

As for the citric acid, I purchased it packaged as "sour salt" at a kosher grocery store in Baltimore. It was $1.89 for 5.5 oz.

vstech · #8 05-01-2007, 09:08 AM

so, in your flushing, you never got the motor up to temp? I think the motor has to get up to temp, I drive around for two days when I do a flush. with the degreaser in, then I flush it well, fill with water, drive it around for a few hours, drain and flush that, then do the citric acid. let it sit in and drive for a day, then drain and flush that REALLY WELL< fill with water drive that around a few hours, then flush really well again, and drain completely, then fill with the distilled water/G05 mix. driving around on the interstate in the summer with the windows down, and the heat on is uncomfortable, but I got nice clear yellow coolant in my system!
John

gorsuchmill · #9 05-01-2007, 10:45 AM

Apparently, it never got up to temp. My belief was getting the engine up to temp allows the thermostat to open, thereby allowing the entire system to circulate. I thought removing the thermostat's innards would effectively open the system regardless of operating temp. It wasn't until a long drive yesterday that I was able to get the temp gauge up to 85C. Oh well, live and learn.

At this point, what do you recommend? I must have some odd chemical mix in the system. Should I just flush until clear, then install the proper G-05 mixture?

pizzachef · #10 05-01-2007, 12:55 PM

Since you haven't put coolant back in yet, couldn't hurt to put more citric acid back in the system and drive with the t-stat intact so that the engine gets up to temp.

You're ahead of me, I've still got the degreaser in the system...haven't put the citric acid in yet. Since you've drained the block quite a few times by now, what's your best way to get at the block drain? I couldn't get to it any way but from below (I can't totally remove the air cleaner for some reason, the oil hose has been messed with and won't disconnect without me doing more damage I think), and that's a pain too, especially lying on my back in water and coolant. When I opened it the first time, the coolant gushed out and went every where, I was trying to catch it with a drain pan, but the stream hits something right out of the block and it literally rains beneath the car.

I'd appreciate your input.
Thanks,
-Geoff

gorsuchmill · #11 05-01-2007, 01:12 PM

Geoff - I have an 87 300TD, so the block drain location may be different. I drive the car onto ramps and reach the drain from below, crack it loose, then spin it a turn or so with my fingers. It rains as well, but a 3 gal bucket (about the height of a 5 gal bucket cut in two) catches most of the fluid. I also pull the lower rad hose where it connects to the rad, which drains 80%-90% of the total. The lower hose is much faster than the rad drain.

I could add more citric acid, but I'm thinking about flushing it clear and calling it a day. As it stands now, I'll need at least two more flushes just to get it clear again. If I were to do it over, I'd start again with the degreaser, otherwise any residual oils/greases that were never flushed out to begin with would render the supplemental citric acid useless. Agree?

When it's all said and done, if nothing else I would have gotten rid of the nasty green in favor of G-05.

dieseldiehard · #12 05-01-2007, 02:07 PM

Quote:

Originally Posted by gorsuchmill

Geoff - I have an 87 300TD, so the block drain location may be different. I drive the car onto ramps and reach the drain from below, crack it loose, then spin it a turn or so with my fingers. It rains as well, but a 3 gal bucket (about the height of a 5 gal bucket cut in two) catches most of the fluid. I also pull the lower rad hose where it connects to the rad, which drains 80%-90% of the total. The lower hose is much faster than the rad drain.

I could add more citric acid, but I'm thinking about flushing it clear and calling it a day. As it stands now, I'll need at least two more flushes just to get it clear again. If I were to do it over, I'd start again with the degreaser, otherwise any residual oils/greases that were never flushed out to begin with would render the supplemental citric acid useless. Agree?

When it's all said and done, if nothing else I would have gotten rid of the nasty green in favor of G-05.

Glad you are getting rid of the nasty green stuff. On an aluminum head that stuff is risky.

The '87 drain valve has a nipple on it for attaching a hose that can go over to a bucket or whatever, this is one of the small improvements that the 124 has over the 123 which use a PITA threaded plug that usually takes a torch to loosen the first time and a huge hex wrench with a long extension on it. I've lifted the engine off the mounts trying to get one of them loose and finally gave up.

When using the citric acid flush I will drain and refill at least 4 or 5 times, running the engine up to heat (thermostat in) every time, I drive about 1 or 2 miles at 50 MPH to warm it up and the thermostat opens and you feel the heater come on (force it on by setting the control to click in the red and set to defrost) The water should be pretty clear on the last flush and not feel slippery.
Fortunately I only have to do this every 5 or 10 years, in between the other flushes are simple drain and replace coolant (MB only).

Jadavis · #13 05-01-2007, 05:48 PM

Quote:

Originally Posted by JimmyL

BTW, where did you get your citric acid for the flush?

I don't know where he got his, but I just found this place:
http://www.esoapsupplies.com/sea_salt_citric_acid.htm

I have not ordered from them, but $8.50 plus shipping for 5 pounds seems fair.

-Jim

JimmyL · #14 05-01-2007, 05:59 PM

Quote:

Originally Posted by Jadavis

I don't know where he got his, but I just found this place:
http://www.esoapsupplies.com/sea_salt_citric_acid.htm

I have not ordered from them, but $8.50 plus shipping for 5 pounds seems fair.

-Jim

Ahhh, thanks for the info Jim. The cost of the acid is reasonable, but did you get a look at their shipping?

Gorsuchmill, I imagine you are just getting some rust water with each flush. I doubt you will ever get it all. Your new stuff will take care of that, as I imagine it isn't enough to worry about.

pizzachef · #15 05-05-2007, 04:55 PM

Quote:

Originally Posted by gorsuchmill

Geoff - I have an 87 300TD, so the block drain location may be different. I drive the car onto ramps and reach the drain from below, crack it loose, then spin it a turn or so with my fingers. It rains as well, but a 3 gal bucket (about the height of a 5 gal bucket cut in two) catches most of the fluid. I also pull the lower rad hose where it connects to the rad, which drains 80%-90% of the total. The lower hose is much faster than the rad drain.

Okay, that's about what I figured. That's the route I have to take too...its not easy to do 5+ refills and drains in a day. I end up lying in a puddle every time after the first one. Might just drain the degreaser and refill with Zerez and see how it goes.

Thanks for the tip.
-Geoff