I had the chocolate milk for engine oil after a blown head gasket. When I drained it I had 4.5 quarts come out. Half a quart must have been coolant. I scrubbed the valve cover clean and shiny with carb cleaner and the head was professionally cleaned. I'm worried about the rest of the engine still having sludge in it. Will it be enough to refill with fresh oil,run to operating temp. Drain oil and refill with fresh oil. I was thinking of then changing the oil again in a couple of weeks.

 

The water and glycol from the antifreeze will get captured in the oil filter. Refill with fresh and use a new filter, run to temp then change oil and filter. Just like you said with a filter (2) twist.

 

How about the cooling system. In this case - whats the best way to rid the cooling system of the oil/oil residue?

 

Drain and refill.

 

If there's a lot of oil, you could do this...

Drain, disconnect upper radiator hose, remove thermostat, leave lower hose open.
Use garden hose to flush lots of water thru block & then thru radiator.
If you can use hot tap water in the garden hose, that's even better.
Put hoses back, fill with distilled water.
Drain & fill again with distilled water, maybe again depending if your tap water is very hard.

Drain, then add NON-pre-diluted antifreeze to get proper mix.
There's probably 2 quarts that won't drain, so use the spec value for total coolant.
Njmodi, you'll need almost 1 gallon of antifreeze. Other years, whatever the book says.

 

I think some cooling system flushes have non-foaming detergents to release oil from the system. Check w/ your local auto parts store.

good luck

 

JimBlake/TexasHonda:

Thanks for your input. My issues are from last year - I had done coolant drain/fills 3 separate times - and mostly it's fine - but I do have a bit of oil residue that builds up in the coolant overflow reservoir. I'll try the cooling system flush from a parts store...

Thanks for your help.