Today i was cleaning the engine up, and when i took the radiator cap off, i saw a tan substance on the top of the liquid. when i stuck my finger in it, it was somewhat chunky. i drained a little antifreeze, and it looked good from the bottom. the engine was professionally rebuilt last year, and i put an aluminum radiator in. I did have to have a patch put on the radiator last year because my fan went through it, and i have not had any problems with leaking. could the liquid be oil? it doesnt smell like oil though. i will try to post some pics of the substance on the top of the antifreeze. thank you for the help!

 

Just curious, how did your fan go through the radiator? ouch. I don't know what the fluid could be, I say step 1 is to flush your cooling system and then keep an eye on it.

 

i mixed some fresh antifreeze with the motor oil i am using, and it did not look anything like what is on top of the fluid in the radiator.......the fan going through the radiator....i bottomed out the headers on a piece of concrete, which in turn angled the fan right through the brand new radiator.....

 

it sounds like it could be some type of stop leak perhaps?? It looks like a brown sludge and sticks to everything metal...

-Gun

 

Maybe its just condensated nasty water stuck up there? Kinda like some cars get really bad on the bottom side of the oil cap...

Like said above, it wouldn't hurt to do a full system flush. The garageI work at charges 69$ to fully flush it out and replace it 50/50. Takes about 30-45 minutes.

Electric fan and adjustable thermostatic regulator?

 

The reason it didn't look the same when you mixed the two together is because when oil is in the water heated to 200 degress and traveling throught the cooling system at high speed tends to mix it up more. Check you oil and make sure it doesn't look the same. Check all your bases.
[align=left] [/align]

 

Before you "flush out" the system do yourself a favor. If you take it somewhere to have it pressure flushed, I would suggest you disconnect the heater core from the system. Connect the two heater hoses together until the flushing is complete. Years ago I cleaned my system and the holes opened up in the heater core. Now I have a 70 mach 1, and if you ever want a really hard job to do one day, then I siggest changing out a heater core in a 70 Mach 1. Geesh!

 

^ thats a good tip right there... ill remember that one. soggy heater cores wouldnt be fun at all.

 

generaly speaking, a brown rubber ring is a stop leak thing