Oil in coolant

4

41blueoval

Junior Member
I drained the coolant out of my banger today and there was a substantial amount of motor oil in it. I drained the oil also and there was no coolant there.
I drained the coolant this summer to pull the radiator to install a harmonic balancer and there was no oil in the coolant at that time. So this is recent.

Where in the system could oil transfer to the cooling system?

My engine was rebuilt 2 years ago, .060 bore, new Burtz head and the block was decked on the top. Engine does not smoke or use oil. Does not run hot. I change oil every 500 miles and there has never been coolant in it. I have about 3500 miles on the rebuild now.
 
that seams to me like a weird thing to happen.
i have never seen that on a model A.
is it an overhead valve conversion?

if not all i can think of is a rust hole of a crack. in the block.
 
Try doing a compression test and a leak down test. My guess is that the oil is coming from a cylinder maybe through a crack or a head gasket.
 
Oval,


do you use a "modern" head gasket?


I had a similar issue after reassembling the engine with the new modern head gasket (I am dissatisfied because since many years a few drops of water were seeping out).


After retorqued the head again with +0.3 m/kg too torque while it was still warm, it was fine.
In my case, it was only a very small amount of oil. We call this "secretion oil". Visually, it looked like a lot because it floats on top and forms an emulsion with the water. I cleaned it with dishwasher tablets for further inspection.
 

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I used a Best brand head gasket with copper coat. When I think about it there are no oil passages in the head gasket area. The pressurized oil is in the cam area. A crack somewhere is what I’m thinking. It’s funny coolant does not go in the oil.
I drained the coolant into a small container then dumped it in a 5 gallon bucket. After 2 pores the entire top was floating oil which I sopped up with shop rags.
Compression is good have not done a leak down yet. Plugs all look normal.
 
The oil film in a bearing generates quite a bit of pressure when the engine is running. That is what keeps the metal parts separated. If you do have a crack where there is a cam bearing it can leak into the water jacket, depending on the location. You will not see the leak when the engine is not running because there is no oil pressure generated. If it is do to the pressure in the bearing then no stop leak will fix it because of the high pressure. I hope you do not have a crack and there is some other reason.
 
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It might also be grease from the water pump thinned out by the heat of the engine. Did you grease your water pump since the last time you drained the coolant? How many pumps did you give it?
 
just thinking out loud here.

the water and oil are quit separate. the oil reservoir where the valves are is as high as the oil gets.
a head gasket has no oil near it.
maybe a valve guide has come loose somehow allowing oiling up through it.. but then you would have two issues the guide and the head gasket.
or maybe oil is going past the rings. from what you say its unlikely.
or maybe a crack in a cylinder
or a maybe rust out. (i have a block here that looks good but is rusted out so it happens)

i think if it were me i would pull it apart.
 
The pressurized oil is in the cam area.
Click to expand...

Are you saying that the engine has a pressurized oiling system?

Could a "friend" have put some oil in the coolant to cause you consternation?
 
Katy,

Nkaminar means, in the case of the Model A motor, the hydrodynamic lubricating film. Not the pressure-circulating lubrication with a hollow-drilled crankshaft.

The hydrodynamic lubricating film is created by the rotation of the crankshaft against the bearing block (even relative to non-rotation). The resulting oil friction from the different circumferential speeds causes the oil to build up a very pressure-resistant oil film within the plain bearing. With correct bearing clearance, oil viscosity, and rotation speed, the bearings slide against each other without metal-to-metal contact; they are hydraulically separated from each other by the pressure-resistant oil gap.

 
Oiling is stock and I have a sealed water pump. I may flush the system and try it again before tearing it apart. Winter season here now so I won’t be driving it for a while.
Most of my driving is a short drive to town 5 miles away. Towards the end of summer I was doing some 50 mile and up drives so maybe sustained higher rpm has something to do with it.
 
The hydrodynamic lubricating film is created by the rotation of the crankshaft against the bearing block (even relative to non-rotation). The resulting oil friction from the different circumferential speeds causes the oil to build up a very pressure-resistant oil film within the plain bearing. With correct bearing clearance, oil viscosity, and rotation speed, the bearings slide against each other without metal-to-metal contact; they are hydraulically separated from each other by the pressure-resistant oil gap.
Click to expand...
I knew all that, I was just looking for clarification of what 41 blueoval said.
 
A prior owner may have had a standard water pump that needed greasing, and he could have over greased it. With your 5 mile trips, you may have not had it up to a high enough temperature to melt the grease in the water passages. The 50 mile trip certainly got her up to temperature. I'd try flushing her out with a grease cutter. Simple Green added to water works, and take it for a good run to get it up to operating temp. Then flush it out several times with clean water.
 
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