Cleaning out the radiator

[ISPKI]

Hey all,

I picked up all new fluids for my 94 F-superduty (Pearly Edwards). Did the oil last night and drained the radiator. Going to do a series of flush and fills with distilled water (my work distills their own) to clean out as much of the old coolant as possible. I noticed that there is alot of loose crusty stuff in the top of the radiator and I can only assume that is also present in the rest of the coolant system. Is is possible to clean all of that out? Is there something that can be added to water that will dissolve it without damaging the rest of the system? There are chunks in the radiator that are over an inch long.

 

[Clb]

I used everything mentioned here once on the 88, including the ford rust rover at $60 a bottle....
Nadda
on rusty crap, it did de grease it tho!

Went and had it boiled out at a REAL radiator shop.

YMMV

 

[bilbo]

A radiator shop local to me was going to boil mine out at an estimated cost of $60. Mine ended up being full of pinholes so they didn't end up boiling it out, but at that cost I can't justify buying and playing with all the chemicals to clean it.

I realize that doesn't do much for the rest of the system though.

 

[Cubey]

I used a cheap Prestone flush kit, an in-line RV water filter, and city water for flushing my RV after it's original lower radiator hose sprung a leak and obviously meant I had to just drain the entire system. I used 2 bottles of Blue Devil radiator flush (I think 3 was proper dosage, but I wanted it less harsh) and drove it a bit for a few days before draining, flushing and draining again, before 50/50 filling.

Before vs after. It sill has some chunks in it today even today but it runs properly cool so I'm not going to worry about it.

You can see that it did help a tiny bit, getting rid of the milky film. If I had put more flush, ran it for longer before draining, etc it might have done a better job. Problem was it was gonna get below freezing after several days at the time, so I had to hurry up and drain the 100% water back out which meant taking out the flush with it. Money was very tight having just bought the rig and needing to fix so much stuff, so I couldn't really afford to buy more flush, despite how cheap it is.

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[Booyah45828]

Try using thermocure by evaporust. It seems to work well in the videos I've watched and is the next thing I'm going to try here in the shop.

I've used vc9 from motorcraft as well. It works good, but it won't clean or dissolve large chunks in the system.

For oil, I use dish machine detergent. And for dexcool sludge I use superclean in the purple bottle.

 

[ISPKI]

Awesome responses. So what im gathering is theres not much concern running flushing chemicals in our system for a while? The crust in the top of my radiator is a white, chalky kind of material, kind of like limescale or calcium buildup. Had generic green coolant in it too which is promising. I have 6 gallons of Peak SCA Precharge ready to go in but want to get my system as squeaky clean as I can before filling it up.

I did notice a tiny bit of green coolant sitting on the radiator top by the inlet hose and I wonder if I have a pin hole leak over there. Anyway to fix that? Can it be soldered/brazed?

 

[Cubey]

So what im gathering is theres not much concern running flushing chemicals in our system for a while? The crust in the top of my radiator is a white, chalky kind of material, kind of like limescale or calcium buildup.

If you look at my before pic, you can see a flake of that stuff mine had/has. A coolant filter would be a good idea but I haven't bothered.

The instructions for flushes tell you to leave it in and drive it. Of course, beware of freezing temps if you don't have 50/50 in it.

I would have waited for warmer temps if the (way too old, original) lower hose hadn't sprung a leak suddenly. I caught it when idling it for vacuum system testing/troubleshooting, so it never ran out or overheated thankfully. Crazy good luck! Turned off the engine and heard water running. It literally just sprung a leak while idling it that day.

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[Old Goat]

I betcha if there is loose crusty stuff looking in the
Radiator, there is more in the engine and maybe the Heater Core.

Pull the upper Radiator hose off the Thermostat housing pipe, remove it and see what crud is in the Stat.
That might give you an idea what your are dealing with.
You are probably dealing with years of prior owner lack of maintenance and neglect.

AS Clb mentioned, you may have to take it to a radiator shop to be cleaned.

2 1/2 hears ago my Oil Cooler puked oil into the Coolant. Fixed the OC, but then there was the job of cleaning out the cooling system. I did about 8 flushes with Dawn Dish washing soap and distilled water. Drove around to get her up to temp and drain the radiator and Block. There are 2 brass plugs on each lower side of the engine. One is forward of the Starter.
Think it is a 9/16 socket.

Then after no more oil, did same amount of clear flushes with distilled water till it was clean of soap etc... even with all the flushing it never did drain out totally clear.

Then filled with a 50/50 mix of fleet charge with the additives. These engines hold 8 gallons of water and you will never get it all out, about 2 gallons hang up in there some place.

I guess I typed this to say, if you flush with just water you will not get it totally clean. You might need to use some type of chemical to clean out the system.

There are several on the market.
Mercedes Benz mentions in their maintenance manuals to use Phosphoric Acid.

EDIT
OOPS: Citric Acid, not Phosphoric Acid, I knew that didn`t sound right.
I even have a 1lb container from MB,.


Goat

 

[ISPKI]

Well I just picked up brake hardware for my daily and they were running a sale on Prestone radiator and coolant system cleaner so I ended up picking up 6 of them. They said 1 is good for a 12qt system. Figure i'll run a few flushes thru and see how it goes.

I will also pull off the radiator hoses and see how they look.

 

[gandalf]

... a pin hole leak over there. Anyway to fix that? Can it be soldered/brazed?

Several, many, years ago one of my vehicles developed a pinhole leak in the top of the radiator, in the brass(?) top housing. Being a firm believer in the KISS theory, I cleaned the area, and applied a bit of JBWeld. That worked like a charm. It's still there.

 

[Clb]

Dump those 9/16" block plugs and install petcock drains in their place SO MUCH EASIER...

 

[Booyah45828]

I was told years ago to use dish machine soap for oil contamination. and that if you use dawn, don't run the engine, as dawn has a propensity to create bubbles=cavitation.

Whatever flush you use. Follow the instructions. Some of them require a neutralizer to be added, and failure to do so will cause issues.

 

[gandalf]

Dump those 9/16" block plugs and install petcock drains in their place SO MUCH EASIER...

The plugs are 9/16"? What thread do they have? Is it NPT?

I'm seriously considering the petcocks, and want to be sure I'm chasing the right ones.

 

[Cubey]

I was told years ago to use dish machine soap for oil contamination. and that if you use dawn, don't run the engine, as dawn has a propensity to create bubbles=cavitation.

Whatever flush you use. Follow the instructions. Some of them require a neutralizer to be added, and failure to do so will cause issues.

Blue devil makes a radiator flush for oil removed, about $12/bottle.

 

[catbird7]

I think Mercedes recommends citric acid for cleaning diesel radiator's. Bought some years ago but never tried it. Still have it somewhere out in garage.