I've got a car with a aluminum radiator & heater core that needs to be flushed.
This car sat for 2 ~ 3 years and ever since it's been a real pain to flush out the cooling system.
Here's what's been tried.
regular flush (using lower radiator hose to drain) multiple times until it runs clear.
reverse flush (thru thermostat housing).
prestone flush kit.
After this the car will be ok for awhile and then starts running hot
and the coolant looks red / brown (rusty) colored.
As if it was never flushed.............

I've been told to use vinegar but I don't know if it's ok with the aluminum
rad & core.
Any advice?

Vineager is relatively weak.


I've used it with aluminum heads (not radiators) without any problems.


I usually go thru several flushing cycles, getting the engine up to full temp with the flush in the system...........

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Try using TSP (get it at paint store) and mix with dishwasher soap (it's non-sudsing). Run for about a day and then flush, it seemed to work, and is cheap.

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Part of Tyrde-Browne Racing

If you have a block drain (passenger side, left of the oil filter) make sure you use that too. I don't know if all blocks had them but it does let out a decent amount of coolant that the lower hose doesn't.

thanks for all the suggestions.
If the vinegar is ok with aluminum heads then it should be ok with this radiator and heater core.
I'll look for a block drain too.
also, what is TSP?

I've used arm & hammer washing soda on heavy equipment,just be carefull,it damages paint.You should also consider that any cleaning agents will ruin your water pump and thermostat,so I only use them when I plan to replace them anyway.

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V8?? We don't need no stink'n V8!!

Do you consider vinegar to be one of these cleaning agents or the TSP ?

TSP is trisodiumphosphate, it's used to clean old painted surfaces prior to repainting.

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Part of Tyrde-Browne Racing

It's also good for washing windows!

And cleaning brewing equipment!

CJ

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Part of Tyrde-Browne Racing

I would NOT use trisodium phosphate to clean any aluminum objects...especially a radiator. Trisodium phosphate is a strong base and WILL corrode aluminum. You are asking for leaks if you do this.

Your best bet is to use the proper cleaning products suited for aluminum radiators. Most of those products suggest numerous hours/days of cleaning action. You will likely have to do this more than once. If you change your coolant as recommended and if you use de-ionized water (i.e. distilled) for your coolant mix your "grubby" water should go away eventually.

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Slanted D150

Thanks for the suggestion, I'll stay away from the TSP.
It's been frustrating trying to get this cooling system to work properly.
I've been driving the car for about 8 months and had to replace the fan clutch one freeze plug and the upper radiator hose.
They've always used a 50/50 mix of coolant and tap water.
It's a 89 model with 104K miles and I was just told that they tried to drain the radiator awhile ago when they opened the drain plug (petcock) it was plugged with crud. They were able to clear that out. When they were flushing it back then, they would fill it with tap water, run it until it got up to temp. and then drain it by pulling the lower hose.
From what I've been told this took about a dozen tries before it ran clear.
That was at least 2 yrs. ago, and it worked ok for awhile but now it needs to be flushed again. When I replaced the upper rad. hose I flushed it at least three times and it was fine for maybe three months.

What I had planned to do is put about a quart of vinegar in it after several plain water flushes and see if the vinegar breaks loose anymore crud.
I was thinking about leaving the vinegar in there for a couple of hours while driving it short distances and getting the temp. up and letting it cool down.
I'm just not sure if this will help

Just because they did this, and you too doesn't mean that it's clean. You'll have to use some type of chemical flush to get all the crud that's inside the radiator. I had to use 3 bottles of flush before I was happy with mine when I had to do this. What this means is drain and flush the system, add a bottle of flush and fill with water. Drive it for like 3 days, then flush the snot out of it, and repeat the process again. Then when all was said and done, I used a bottl of rust inhibator just to cover my butt. That was 5 years ago, and so far so good.
Preventive Maintainance--- Do it when you need to do it, not when you have to do it!

Thanks for the reply.
As you can tell i'm getting into this mess well after the problem started.

I had similiar issues with my truck. It literally sat under a pine tree for 15 years (and started up with merely the addition of a new battery).

My solution to the mucked up radiator was to clean the cooling system with the most agressive cleaning products sold for the job. I did it twice, the first cleaned out the radiator--I left it sit in the radiator for hours before running the engine. The second time I cleaned the block, etc by recirculating the cleaner as directed. I then drained the system and reverse-flushed it using a garden hose connected to the heater hose.

The net result of this was a leaky radiator (it was a brass radiator), a chemically etched thermostat and water pump, but a very scale free and mostly rust free coolant system.

I replaced the radiator, the water pump, hoses, and the thermostat--I refilled with coolant and di-ionized water/distilled water and have had zero problems since then.

Most domestic water supplies have dissolved solids in them that scale out in the cooling system--using distilled water (i.e. pure H2O) really does help manage coolant scale issues.

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Slanted D150