b_evans06

iTrader: (1)

I just recently finished putting in a 4.8 in my 84 cutlass. I have put about 300 miles on the swap in the last 3 weeks and this morning I was checking over some things and noticed foamy brown antifreeze in the radiator. I checked the oil and it is still just as clear as when I put it in before starting the motor. The motor came from a local junkyard so I assume it had been sitting for awhile. I did not ever pull the heads off the motor as it was clean on the outside and the bottom end looked good (spotless inside the valve covers and oil pan as well as cross hatching on the cylinder walls). Could this brown foam be from not flushing the motor before filling the system? The motor had some coolant in it that ran out while moving it. Could old antifreeze leave rust or residue inside the motor that flushed out once it started?

ss.slp.ls1

iTrader: (36)

If the oil looks good and you are not loosing pressure in your cooling system, I'd do a complete cooling system flush and fill it up with fresh coolant/distilled water and call it a day.

b_evans06

iTrader: (1)

The car hadn't been started in a few days and when I took off the radiator cap I could hear it letting off pressure so I assume the system ok as far as that goes and the oil looks just like it did when I poured it in the motor.

greenturtle05

iTrader: (6)

flush the entire system and put some new coolant in and you should be good. Did you have a leak on your previous motor?

b_evans06

iTrader: (1)

I bought the car as a roller that didn't have a motor or radiator. The cooling system is all new except the water pump.

RPM WS6

iTrader: (3)

What about the heater core? Original to the car? Maybe there was junk in there.

Flush the system and keep an eye on it. Hope for the best.

shaun

this could be the case old crap in the core got broken loose and went through the system.
i would flush it out real well dont want crud going in the heads and block.

Canbarelygo

what ive seen of this is that this is what happens when you mix red and green antifreeze. when you mix the kinds that arent mixable it turns into this nasty nonsense that looks like the inside of a brownie lol.

umm if that what this is then when water hits it, it should just kinda "melt" and flow away. if this stuff is your problem then take the radiator out and flush it out for about 10-15-20 mins with a water hose (depending how big of a **** you are and it should be good. then while radiator is out just run a water hose through the block for 20 or so minutes maybe more (again depending on how big of a **** you are) and you should be good to go man.

like i said try runnin water on the foamy stuff and if it kinda "melts" and flows away then thats your problem. hope this helps

justin455

Might this be what you are speaking of?



Everyone is right. Flush it well. This is dexcool that has been left in too long and has either come into contact with good old green stuff or air. Once this happens it's actually a corrosive substance that eats all the good little plastic parts (namely intakes) that GM uses. It wasn't as maintenance free as GM advertised.

Best bet is to flush it and use green. You can use dexcool again with no problems as long as you keep an eye on it, but I prefer green anyway.