[azbirds]

I'll try to make this short. My 72 bird sat for a looong time and it had a lot of crud in the cooling system. A mechanic friend said they've used CLR to clean cooling systems. After using it and flushing it really good I've got what can be described as brown sludge sticking to the cap and who knows where. What can I use to clean up this mess?

[694.1]

Mark:
I will be following this too.
The old 2 part acid cleaner & neutralizer has been off the market for a decade or more (Imagine what it would do to an Aluminum radiator but I have collected a pretty good supply of it @ swaps over the years and will be using some on a project soon.

[azbirds]

Wow!! I though someone would have chimed in by now.

[beertracker]

Prestone radiator flush worked for me and it's cheap. bt

[bendutro]

Evaporust?

[Bluesugar]

Drain a little fluid out of radiator(with engine cold),pour in a quart of vinegar in its place,
fire up and warm up on a 30 minute cruise,pull the car in your service area,leave in neutral or park,leave motor running,carefully loosen bottom radiator hose at timing cover,(have gloves on,don't let fan blades hit you),pull hose off and then shut engine off,let drain and cool,repeat,refill with water when cooled,run and drain again,flush and refill with antifreeze,check level when cold,..done.

[Bluesugar]

I will now retract my suggestion about pulling the bottom radiator hose off while engine is running,this is a bad method and also a dangerous foolish one if not done correctly...also don't remove the rad cap while engine is turned off if engine is hot..Flushing your engine with vinegar holds true however you decide to do it.

[Squidward]

I have used the method described by Bluesugar except for the part about homemade finger pepperoni.

I drained the entire thing and flushed with a garden hose attached via a T-fitting on the heater hose line. I also disconnected the upper and lower radiator hoses at times, plugged them with my hand, let pressure build up some, and then let the water power dump. I then filled with water and added the white vinegar. I ran it for a bit to circulate through the system, let it sit for an hour or so, then did the power flush/dump again to get all the vinegar out (well, dilluted down to effectively nothing). It helped get the scuzz out. Refilled with distilled water and antifreeze, and called it good.

The brown sludge shows up eventually, so I consider this just a maintenance item to put on my list of periodic crap to do.

[azbirds]

Thanks guys. Never heard of using vinegar so I will give it a try. Used Prestone cleaner and it worked to some degree, but needs more. I usually don't have overheat issues with my cars but this one sat for a long time(Body shop horror story!!) Has a new Desert cooled Rad, new HD clutch on the fan and its got a new t-stat and water pump with cast impeller. I made sure the divider plate was touching the impeller without gasket. initial timing is set at 14 with total 36 at 2500. Cliff's Q-jet. I thought all my bases where covered, but apparently not.

[Blued and Painted]

I like to circulate what ever is used with thermostat removed. Then after final rinse, add a new thermostat and coolant.

[azbirds]

I did remove the T-stat for cleaning, and a new one took its place. I used a 165 fail safe.

[chiphead]

Reviving this thread

I've got some brown sludge/silt in the radiator. I've flushed it twice now and its come back again. New aluminum radiator, water pump, etc. The engine sat with the intake off for some time before I got it. It looks like some squirrels may have hid acorns in the head's water inlets, because I've found bits of acorn in the radiator. But mostly it's rusty coolant. It runs cool around town but builds heat on the interstate.

What's the best way to flush this out with the engine in the car?

[nUcLeArEnVoY]

I had a friend blow a head gasket after using an evaporust cooling system cleaner, so for car's with an older set of gaskets or even original gaskets, I'd err to the side of caution and just do repeated drain and fills until water comes out clear... which, sadly, may never happen in really old cooling systems without those cleaners. Kind of an iffy prospect.

My 79' has a fairly clean cooling system, and every couple years I back flush it through one of those silly little tees you install in the inlet heater hose. Works pretty well.