ford gpa g504

Hello out there,
Perhaps someone can advise me on this one. For some time now I have had oil on top of the coolant in the radiator, which I have been ignoring hoping it would go away. However it does seem to be getting progressively worse and I plan to have the motor out at the end of the swimming season and sort it. Now, it is my understanding that in a sidevalve motor with no oil to the head this can only be caused by a cracked block and I have steeled myself up for all this will entail. However, I noticed a paragraph in the Maintenance Manual which states 'A heavy layer of oil on water in radiator may indicate leaking gaskets or other injury in cooling system or engine lubricating system'. My question is this, which gasket could cause engine oil to get into the cooling system? Any ideas? I should add there is no sign of water in the engine oil so presumably the problem is somewhere on the pressure side.
Thanks in advance.
Bob Skinner

Hi Bob,
First or step is head gasket.
Bubbles in the radiator with full trottle?
Yes? Cyl. head off! Looks an easy job but it is a GPA so never easy.
New gasket is maybe the solution but you need also a very serious check of the cyl.head.
When te head is not 100% use first type asbestos gasket but when 100%: copper gasket I prefer. If all this looks OK what next? Some water in the engine oil maybe?
This can be very serious. Ford engines are more sensitive for cracks when several-or a lot of times overheated. To check this - I think - you have to take out the engine.:-(
When there is a crack in a cylinder new cyl. liners (bushes) can solve the problem maybe.
A lot of work and expensive. This Is nearly a complete overhaul!
Raymund van Riel has a solution when the crack is near the oil pump hole.
Hope this will help you a little bit to fix your GPA before Amphib 2011 in Switserland!
Kind regards, Jan

Hello Jan,
Thank you for your thoughts, is it really possible that the head gasket can cause this? I have been told that there are no oilways to the top of the block so where would this oil come from? Are there any gaskets where the oil and coolant are close together, water pump for example. Otherwise I agree it is a crack in the block, there is a company near here that can repair blocks, either with a sleeve if it is in the distributor drive housing or with a ceramic if it is an internal crack. The repairs are 100% I am told and a lot cheaper than a replacement block. I am going to flush out the whole cooling system today and then see how bad the problem is after a run. There is definately no coolant in the engine oil so I think I will risk doing Switzerland unless It gets a lot worse.
Best wishes
Bob

Hello Bob,

When the piston oil rings are in a very bad condition oil comes on the cylinder top during every crank/start procedure.
It is possible that the piston is pressing a little oil in the cooling system during the strokes when the head gasket is in bad condition.
Your first mail says that is was just a little oil in the cooling system.
Hope for you its not a crack!
Regards,
Jan

Hello Bob and Jan,

There is no way oil can come in the radiator other than someone pooring it in there.
The side valve engine has no moving parts in the head, hence the head gasket does not seal off oil return holes or oil fed holes.
This is not so with an overhead valve engine where the rockers need lubrication and the oil flows back through the head gasket.
Another reason why it is very doubthfull oil enters the coolant is that the coolant is under light pressure.
The sump is not under pressure.
So the water would rather enter the sump via pitting in the cylinder walls or a cracked distributor bore ( often experienced with Ford made blocks ).
First thing to do is taking a sample of the coolant pollution and let it dry.
It will not be oil.
If probably will dry to a brown powder.
Most likelly something is wrong with the anti freeze.
A head gasket that leads to the combustion chamber would make the engine consume coolant all the time, or at least give you coolant bubbles and bursts.
If you would experience loss of coolant regulary, it might be consumed by the engine, and polution from exhaust gasses might polute the coolant as Jan said.
But again it would not be oil as oil get's burned before the high combustion pressure can push it into the water jacket.
I suggest you to flush the cooling system with plane water.
Fill and drain it a few times and run it with fresh coolant.
Most likelly the pollution will dissapear or decrease.
Also, take a torque wrench and check the head bolts.
Most people do not retorque the head properly, and this might result in a leaky gasket.
If the gasket leak is not yet established, you might get away with a retorque.

This link is from a similar issue on a Dodge WC that has more or less the same engine.
http://www.g503.com/forums/viewtopic.php?t=158058

Hope this helps,
Luc Coesens
Belgium

Jan, Luc,
Thank you for your input. The link was very useful, the 'contamination' in the coolant looked exactly like the Dodge photo in the link. I have to say I am sure there is oil in the brown 'goo', it did not dry to a powder but stayed a slippery brown slime. I think Jan has a point with the head gasket theory so I have pulled the head and installed a new gasket. I have drained and refilled the system 5 times, running the motor each time. The 1944 thermostat was also stuck open so I have installed a new one and the motor now runs at 170 rather than the previous 140. I have retorqued the head again. This weekend I have to do a 150Km round trip so we shall see what the coolant looks like after this. I will let you know the result.
Bob

Hi All,
a little late but here is an update on this oil in the coolant thread. Since I changed the head gasket and flushed the system I have driven many miles and spent a lot of time on the water (Switzerland & Norway). I have to report that there is no more contamination in the coolant, it is as clean as the day I put it in. So I have to conclude that it was the head gasket causing the problem and Jan's theory was correct.
Regards
Bob