I recently bought a 68 250 CSpecial. Everything looks fair for a truck it's age and price 750.00. However, I failed to check under the radiator cap. I had been told that the radiator was replaced in the last year... Oops poor excuse.

A very nasty sticky milky brown goo is stuck to the cap and sits purhaps several inches deep atop the water in the radiator. A check of the dip stick reveils no water in the oil. I've never seen anything like this.

I have a radiator shop operator/friend that I hope to get with some time this week, work permitting. In the mean time I'd like to get someone's comments on a possible cause. Mike

 

Sounds like a blown head gasket..

 

I had a similar incident a few years back. Turned out to be an oil galley cracked into a water jacket. A blown head gasket usually puts water in the oil, not vice-versa.

 

I have had blown head gaskets put oil on the rad, and vis versa coolent in the oil..

 

Guys Thanks for the quick responses. I haven't been to see my friend yet, but expect he agree with you. As it turns out a set of heads, among other things came with the truck. I'd like to do more than just replace the gaskets. So I'll get those down to a shop he'd recommend and see if they might be ready for use. What a mess that has made of the radiator. I hope I can get the system flushed out. Mike

 

could also be a tiny crack in a cylinder head between the oil galley that feeds the rocker stand and the coolant cavity in the head.... water pressure is only about 10 to 15 psi and that might not be enough to leak any noticable amount of coolant into the oil but the flip side is, oil pressure is 30-40 psi or more and will find it's way through a crack that wont leak water. I'd probably yank the heads and get them magnifluxed before I pulled the whole engine out. To check for small amounts of water in the oil... pulling the dipstick won't give you an answer... let the motor sit overnight and loosen the drain plug... if it starts dripping oil... no problem, if it drips a few drops of coolant first... then you have a problem. Oil floats on water and water will always collect at the bottom of the pan. Unless there is a LOT of it in the oil, the pump might not pick it up and churn it into a milkshake with the oil.

Permatex makes a heavy duty radiator and cooling system cleaner that will take the crud out of anything. I use it for cleaning out cooling systems on large ag equipment and trucks... it'll melt down anything in the system that aint metal or rubber... if you have a radiator that has a lot of lime scale in it... it's gone after this stuff is used.... You cannot use this in an aluminum engine or radiator... it will eat it up.
Permatex part # 80030