coolant in oil

[Buttercup]

Bought a 66 390 from the original owner, and it ran well. It had only been driven 500 miles per year for the last 15 years and lived in a heated garage. Within a few days and about fifty miles of driving it began to run worse and worse, and the oil is a milky light brown. Car has had a tuneup and carb rebuild. The way it runs suggests vacuum leaks to me. I'm leaning towards replacing intake manifold gaskets, but is there any way to determine if that is the problem? Could it be head gaskets as well?

Thanks in advance!

[Harley Eaton]

Yes. It could be head gasket. Look for rusty spark plugs.

[redbird1]

It is head gasket changing time.
Bob.

[Buttercup]

Thanks, Harley and Redbird. Is it possible the headgaskets have degraded with time and lack of use, or is warpage more likely? Also, headgaskets wouldn't cause vacuum leaks, would they?

[redbird1]

Originally Posted by Buttercup

Thanks, Harley and Redbird. Is it possible the headgaskets have degraded with time and lack of use, or is warpage more likely? Also, headgaskets wouldn't cause vacuum leaks, would they?

I don't think warpage is the problem.
That usually only happens as a result of extreme heat for a long period of time.
A broken head gasket will affect vacume.
Are you getting any backfirie, or popping through the carb?
Those are definite signs of a blown headgasket.
The fact that it is running rough also indicates a blown head gasket.
Bob

[Buttercup]

It definitely pops through the carb. Sounds like I'm pulling the heads. Two more questions, if you'll indulge me:

- if it's been driven 30 or so miles with coolant in the oil does that damage the motor?

- is it possible to test the block and heads for warpage myself while the block is still in the car?

Thanks again! This forum is great.

Steven

[redbird1]

Originally Posted by Buttercup

It definitely pops through the carb. Sounds like I'm pulling the heads. Two more questions, if you'll indulge me:

- if it's been driven 30 or so miles with coolant in the oil does that damage the motor?

- is it possible to test the block and heads for warpage myself while the block is still in the car?

Thanks again! This forum is great.

Steven

That amount of miles shouldn't do any damage to the engine, but to be on the safe side, once the enging is back together, and running,(with a new oil change and filter)
run the engins for 50 miles, and drain the oil, and put in new oil, and filter.
As for checking to see if the parts are warped, you can always use a metal straight edge to test for warping.
Do this once the heads are removed.
You can check both the block and heads.
There are tools especially made for this, but a good metal straight edge should give you a pretty fair idea if you need to mill the heads.
Bob.

[Buttercup]

Great! The motor's probably not going to need to be pulled out of the car, which is good news because my garage isn't set up for that.

Thanks again, looks like I have myself a good winter project now.

Steven