motor oil in cooling system-100/4

[jayarbee]

This car is finally running since the engine was rebuilt in 1987. It sounds good, has good oil pressure, and maintains approx. 200 deg water temperature. After about 20 minutes of about 800 rpm running I shut it down and let it cool. Opening the radiator revealed motor oil floating on top of the water. I used a new head gasket, coated both sides with Hylomar, and torqued the nuts per the book (65 lb/ft). My son asked if I had sealed the head studs, as is necessary on small block Chevys. I had not, but I had not on other 100/4 engines either. Any help out there?

 

[Healey 100]

Suggest you drain the radiator, refill and try it again. There could have been residual oil left in various water galleries that floated to the top of the radiator once the water heated up. Chances are you will see a lot less oil on the second running of this engine.

I have not heard of leakage thru the cylinder head studs on these cars. Water leakage OUT of the head is common, most 100's including mine, have a bit of water standing on the boss with the engine serial number on it.

There are not too many ways for the oil to get into the water, except perhaps around the pressurized oil passage between the head and the block. Of course cracks in the head or block around oil galleries could be a problem -- but most of these galleries are not near the water jackets.

If it still passes oil into the water, you will probably have to pull the head and check for flatness, and perhaps add some sealer to those studs.

All the best,
Bill.

 

[Dave Russell]

Jay,
Sorry you are having problems.

There is only one place where the oiling system comes close to the cooling system. There is a rocker arm oil feed passage that comes up through the block & into the cylinder head. This is a 1/4" hole that is about 1 1/4" inboard of the outside head surface & directly under the back intake port. This hole comes to within about 1/4" of the water hole in the gasket. A leak here could do it.

My shop manual actually shows 65-70 ft lb for the head nuts, but I doubt if the extra five will help.

The only other thing I can think of is a tiny crack some where in a casting.

The head studs are normally in blind holes, there are only three of them that are on the inside of the engine, & the top washers should seal them. Besides, this would only be a problem if you had the opposite situation. Water getting into the oil.

I would just mop the oil off the top of the water with a paper towel & watch it for a while. If the problem isn't too bad, I have read of people continuing to mop off the oil for as long as five years & no other problems. Unless it IS the head gasket it will be very hard to find the leak.

Good luck,
D

 

[jayarbee]

That's sort of what I thought, in fact I had considered wicking up as much as I can and then draining the rest of the water----Ohmigod, I just this second realized where the oil came from! Before I installed the head I demonstrated to my 7 year old grandaughter the action of the pistons going up and down in their cylinders, not noticing till the demo was finished that I had just pumped a good sized puddle of oil onto the top of the block, which proceeded to flow into the adjacent cylinder, over the edge of the block, and into the water jacket! (picture a graemlin slapping his forehead here). Thanks for the help, guys.

 

[Dave Russell]

Okaaay!