Cooling system clean/flush

[NutmegCT]

What product(s) can you use to clean the cooling system?

1960 Mercedes-Benz 190b.

Remove scale and sludge in radiator, water jacket, heater core - that kind of thing.

I think I remember reading about a soda compound you pour into the radiator, drive a few days, then drain and refill the system. System is now a 50/50 Prestone mixture - one year old.

Any suggestions on things you've done yourself?

Thanks.
Tom

 

[JPSmit]

Only thing I did was use CLR on a heater rad - and it was out of the car. On another board i frequent, they use denture cleaning tablets. I would be inclined to just buy some rad flush.

 

[CaptRandy]

We used to add a cup of Tide to the rad and run it for a couple hours to circulate, then drain and refill with water to rinse out.

 

[AN5Sprite]

Don't do it.

My opinion, but to me it's one of those things that can do way more harm than good. You could loosen up some junk that just gets stuck somewhere that's really bad, hasten somethings failure etc.

I bought one of the OTC radiator flush products. The wiseacre at NAPA said, "don't use it, you'll regret it". I said "sure, sure I will". Within 2 weeks the head gasket on my Sprite let go. It eroded from a water passage to the #1 cylinder. I Can't prove they are directly related but...While I was replacing the head gasket, I kept asking myself; Why did I do that anyway? I have no idea.

My $.02

 

[DrEntropy]

Only sure and safe way is to rod out the radiator, disassemble and "boil" the block. Short of that, the only "flush" I'd do is to pull both hoses, then back-flush rad and engine separately with a garden hose until the water runs clear.

I've seen what Steve described too many times.

 

[NutmegCT]

Thanks for the comments. The cooling system actually seems to be working fine - no overheating, runs at correct 180F temp. Coolant is "green and clean".

The specific issue: the driver side heater core doesn't get very hot. Starts out hot, then cools off after driving a few miles. Passenger side heater core gets hot and stays that way. Valves are open. Air flow is 100%. Seems there's some crud in the driver side heater core.

Is there any danger in back-flushing the heater core itself? Any tips and techniques? Not a problem to disconnect the in and out hoses at the core.

Thanks.
Tom

 

[AN5Sprite]

Tom,

Can you get that heater core out easy enough? It's probably worth back-flushing it, but it would be a cleaner job out of the car is my thinking. Then you can inspect it too...

 

[NutmegCT]

Thanks Steve. That core is riveted into a cardboard air duct assembly. Try to remove the core, you pretty much destroy the whole system. You can see the heater core in the duct here - core has the brass pipe coming from the top:

The pipe on the bottom is tough to get to, but at least you can get in/out access.

 

[AN5Sprite]

Drill the rivets?

Also, I ran across this:
https://www.ebay.com/itm/Mercedes-Benz-180-190-219-220S-Right-Side-Heater-Box/221334182976?_trksid=p2047675.m1985&_trkparms=aid%3D444000%26algo%3DSOI.CURRENT%26ao%3D1%26asc%3D19049%26meid%3D3323929658716971951%26pid%3D100012%26prg%3D8643%26rk%3D1%26rkt%3D5%26sd%3D360790990797%26

 

[NutmegCT]

Could certainly replace the whole unit, but as it's sturdy, I think I'll concentrate on flushing that core.

Started the trip back on September 27; plenty of heat from that core when needed. But over the next 7000 miles, the core gradually produced less heat, altho' the passenger side core continued working fine. Plenty of air flow from both ducts, just not enough heat in the driver side.

Had lots of fun while driving across Nebraska. Even with engine at normal temp and driving at 60 mph, the winds and damp weather made both heater cores somewhat less than torrid. Remembered an old trick I learned from my dad back in the 1960s: slide a big paper bag down in front of the radiator. Worked like a charm.

Thanks.
Tom

 

[PAUL161]

Tom, Is that a honey comb core or a straight tube core? If it's a straight tube unit, I'd try and back flush it straining what comes out through a cheese cloth to see what you get. If it's a honey comb core, the best thing is to replace it as they have a lot of places to collect debris and are a bugger to get clean, if at all. Chrysler was great for using the honey comb cores in their earlier years as they give a lot more heat transfer. JMHO. PJ

 

[Deleted member 8987]

Used to be able to buy a 2-part flush. DuPont made it. Pour the big top half in, run it for 20-30 minutes, drain and flush, fill, add the neutralizer, run, drain, flush.
Haven't seen it in some time. Was the only thing that worked on old flathead Fords.

DuPont No. 7 cooling system flush that contained oxalic acid, the kit had an acid neutralizer.