black coolant

[merlin3]

on my 72 c10 509 merlin 3 i have been driving the truck all summer but after the top radiator hose popped of i was refilling the radiator with the type of funnel that you can adapt a radiator cap to the bottom,when i look in the funnel on the top the coolant is black but when i crack the petcock green coolant comes out,i also noticed i am loosing oil somewhere but not burning it or leaking.thanks for the help

[WarMonger]

Originally Posted by merlin3

on my 72 c10 509 merlin 3 i have been driving the truck all summer but after the top radiator hose popped of i was refilling the radiator with the type of funnel that you can adapt a radiator cap to the bottom,when i look in the funnel on the top the coolant is black but when i crack the petcock green coolant comes out,i also noticed i am loosing oil somewhere but not burning it or leaking.thanks for the help

I think you answered your own question. water and oil don't mix. Your loosing oil... found it.

[WarMonger]

maybe do a compression test or leak down

[merlin3]

head gasket?

[LongBox]

Whenever I've run into coolant contaminated with engine oil, it makes a kind of thick goopy mix, usually coloured a kind of creamy brown. Hope this is not the problem you have.

[merlin3]

no not goopy,creamy brown,same consistency as coolant just black with some residue.

[special-K]

My guess would be exhaust leaking out combustion chamber by way of head gasket or crack into water jacket. I've seen that happen without coolant getting into oil.

I just fixed my '72 350. I had a frozen in head plug that led to pulling head which led to discovering a crack in head with coolant traces evident which is why plug froze. The coolant was blackish but the engine was clean as a whistle inside and so was oil. It just burned off the coolant. Only smoked when I started it (after sitting for days) and a valve would be sticky. Cleared up and ran fine once warm. It didn't use much coolant and this was going on for a while. I was figuring on needing an engine. New heads and it runs better than ever

[merlin3]

special -K i did notice a slight oil leak drivers rear area of head were head meets block,wonder if that has anything to do with it.

[Grumpy old man]

Pull the plugs , if you find one that looks steam cleaned you found your leak .

[merlin3]

well,i pulled the plugs and found #1 plug almost white and the rest very dark with carbon,[still need to adjust carb.]then i took the spill free funnel off, looked in the radiator and could see perfect green coolant,so when running with the funnel is the only time i see black coolant [in funnel]i have all holes in the intake and water pump for heater hoses plugged because i do not have the heat hooked up,very confused here-thanks for the help.

[Grumpy old man]

Switch the "white "plug with one of the dark ones and drive it a bit and pull those two plugs again , if the #1 plug is white again you have found your leak in that cylinder , be it a Crack or bad head gasket . Before getting too crazy dump some Bars head gasket sealer in the radiator and see if that solves your #1 cylinder problem . Just a very small amount of water/coolant will give that steam cleaned / white plug look .

[special-K]

Did it ever get hot? This is a new engine, right? That sure sucks if it is. If not from getting hot the problem is either from poor assembly or poor casting/materials of head. I'd do the plugs swap and see what you get, although I think we already know what that is. Still, no sense in breaking anything down before doing such a simple test. I've used system sealers before, but only on older engines. I'd want the issue corrected properly if I had a new expensive engine I hoped to get a zillion more miles out of.

[merlin3]

i purchased the engine from a guy who bought it new and put it in a 67 corvette only to put about 200 miles on it,i have about 30 miles on it now and yes it does get a little hot 200-210 at idle,just checked the oil-no water,will switch plugs and run it now will let you know thanks