MB Part Number A 001 986 21 71 - PeachParts Mercedes-Benz Forum

hispassion · #1 02-20-2010, 12:38 PM

Greetings!

After performing a head gasket repair on my 300CE/M104, I have an oil residue in the coolant tank and suspect oil throughout the cooling system as the upper rad hose has begun to swell under pressure.

That said, I purchased the Cleaner (A001-986-21-71) from my local dealership. And while looking for how to mix it, I can only find reference on here and in other forums to a 3% mixture. Okay, so I may not be the sharpest knife in the drawer, but I'm not a neophyte either. What is meant by a 3% solution? 3% of a small amount of water or 3% of the cooling system capacity or 3% of what?

The only thing that concerns me right now is the how much chemical (powder) is too much. A 3% solution doesn't make sense to me. I don't want to corrode things internally, but I also want it to emulsify with the oil so it will flush out.

So, being anxious to get things done, I drained about a quart of coolant, added a couple or three tablespoons of powder to that coolant and reintroduced that mixture to the cooling system. I then started it, warmed it up to just over 80°C, raised the rpm to about 2500 rpm for 2 or 3 minutes and then shut it off. I will be flushing the entire system, including the block and refilling it with water and will then do it again after which I will fill it with 50/50 coolant. If this sounds good, then I guessed correctly. If not, and I need to use the entire bottle of powder (Disodium trioxosilicate pentahydrate), then I guess I could do it again.

Any thoughts? Thanks!

RichardM98 · #2 02-20-2010, 01:41 PM

Generally, a 3% solution is by weight. That is 3 grams of solute in 97 grams of liquid. It can also be defined by volume especially when both components are liquids. Then it would be 3 ml of part a and 97 ml of part b. Often it will be described as "measure 3 ml of part a and dilute with part b to 100 ml."

With aqueous (water) solutions it doesn't make much difference since a milliliter of water weighs about 1 gram. Also, the concentration of cleaning solutions isn't super critical. But 'more is better' doesn't always apply either.

BTW, for reference, 1 oz is about 30 grams.

I would assume you need to make enough 3% solution to recirculate in your cooling system. A quart of liquid is about 900 grams. Figuring about 10 quarts in the cooling system, you would need 270 gr (about 9 oz) of cleaner in 10 quarts of water.

You might want to rinse the system a couple of times before adding 50:50 coolant just to be sure no incompatibility between cleaner and the corrosion inhibitors in the coolant.

Good luck.

atikovi · #3 02-20-2010, 02:39 PM

Why do you think a small residue of oil in the cooling system is such a bad thing? The upper radiator hose probably swells under pressure because it's old and needs to be changed. I would just remove the coolant tank and clean that instead of trying what you are doing which is probably for something like a catastophic failure of the transmission cooler in the radiator.

hispassion · #4 02-20-2010, 03:37 PM

Any oil in the cooling system is a bad thing as far as I'm concerned with my vehicles.

The hose was new when I did the head gasket 6 weeks ago, so it's not old.

Yes, the hose swells under pressure, about 20lbs of it.

I have a new coolant tank and will be replacing it, keeping the old one as a spare.

The radiator was new this past summer, so "nope" on the catastrophic failure of the trans cooler.

Thanks though.

atikovi · #5 02-20-2010, 03:47 PM

If you stick your finger in a bottle of new antifreeze you can feel how slippery it is. It has oil in it to lubricate the water pump and keep the rubber seals from leaking. While not motor oil, it's some type of oil nothing the less. Hoses are designed to resist deterioration from under hood chemicals so I wouldn't blame the swelling on a trace amount of oil.

hispassion · #6 02-21-2010, 10:57 AM

I have been doing engine repair for over 35 years, and have stuck my finger in a few places (including antifreeze) and know how slippery it is.

I am aware of antifreeze having lubricating properties, but I don't think it's got anything to do with engine oil. Possibly some type of silicone or similar chemical.

If I can't blame the swelling hose on the oil in the cooling system, what should I blame it on?

atikovi · #7 02-21-2010, 11:06 AM

Thats strange. Is there a date code on the "new" hose? Could it have been sitting on the shelf for the last 5 years exposed to ozone before you bought it? And why only the upper hose? Why isn't the lower hose swelling as well?

hispassion · #8 02-21-2010, 11:18 AM

Quote:

Originally Posted by atikovi

Could it have been sitting on the shelf for the last 5 years exposed to ozone before you bought it? And why only the upper hose? Why isn't the lower hose swelling as well?

Unlikely it's been sitting around on a shelf, though I don't know. I buy my parts from auto*haus*az (broken to get past the peachpart filter) and have purchased 3 or 4 of these over the past few years. The also process about 500 orders a day.

Oil is lighter than coolant and rises to the top. The upper hose and tank is the highest point in the cooling system.

Anyway, I think the chemical I used to emulsify the oil has done it's job. We'll see if (and hope) the oil residue doesn't come back.

atikovi · #9 02-21-2010, 11:47 AM

A little oil goes a long way. Whenever I drain the cooling system to change something and the cooant was recently replaced and I want to reuse it, I always get a film of oil in the drain pan just from the coolant flowing down over some greasy part below the radiator drain. It takes forever to get the pan clean again.

hispassion · #10 02-22-2010, 01:39 AM

Thank you RichardM98. Your explanation was quite helpful.

samiam44 · #11 02-23-2010, 09:47 AM

Make sure your rinse the system well- maybe a few flushes(I'd say twice as a minimum). Drive it around and drain it. Make sure the heat is on so you get residue out of the heatercore too.

Agreed- hose swelling is oil.

Are you going to do citric acid flush as well?

hispassion · #12 03-27-2010, 05:40 PM

It's been several weeks and all looks good. I may check the coolant to see if it is keeping it's properties, even though I believe it is. Thanks guys.

JohnM. · #13 03-27-2010, 07:27 PM

I put about 1500 miles on my car when it just started getting oil in the cooling system. I did the head job, and it took about 20,000mi to finally get the system clean. I did two flushes, new radiator, new hoses, new expansion tank, and constantly wiped out the excess oil from the expansion reservoir every month or so. It takes a long time....I was quite concerned as well. But the coolant has been spotless clean for the last year or so.