Alan is having trouble with his Ford 4600 which is getting oil in the water, here’s what he has to say…
I have both your engine rebuild and hydraulic overhaul DVD’s but unfortunately for me they cannot help me with this wee problem and was wondering if you could possibly point me in the right direction?
I have a ford 4600 wich has oil mixing with the water and assumed the head gasket was damaged. I changed the gasket and the tractor ran ok for about a day but started mixing oil with the water again. There was not any obvious damage to the old gasket and she had a new short motor about 13 years ago and has not done excessive hours since. We have always used good quality antifreeze since so I am really hoping it is not damage to the block!! I didn’t get the head skimmed when I did the head gasket as every thing looked ok. I am going to strip it down again in the spring when i get time and was wondering where else could the oil mix with the water assuming the head gasket is ok. I tinker about with the engines and not a time served mechanic so would be greatfull for any advice you could give. I do relise you will be extremely busy but any help will be greatfully received.
Here are a couple of suggestions…
It could be a cracked cylinder head but I think this is not very likely.
It could be a porous block (which usually manifests itself as water in the oil, rather than oil in the water). What did they do when the engine was overhauled? Did they just true up the bores and fit oversized pistons? Or was it machined and liners fitted? Often the bores have just been trued up and oversized pistons fitted (as its a cheaper option) but now this means the wall of the block is even thinner than it was originally and it is likely that a crack or fissure has occured in the block allowing the water to passs through.
This is common with Ford engines and is known as ‘porous block’ (as the cylinder walls are so thin). This happens regularly with with slightly newer models such as the Ford 6610 and 7610 (even when the cylinders have not been bored out).
If this has happened then it can have cast iron sleeves pressed in which solves the problem. I would suggest measuring the pistons and comparing that measurement with the spec of the original pistons in order to determine if the pisons have been replaced with oversized ones. If they have, then I believe ‘porous block’ is likely to be the problem.
Some Ford tractor have an oil cooler in the bottom of the radiator and it is possible for that to split, this manifests itself as oil in the water so is a distinct possiblity as the cause of your problem.
Hope that helps,
Steve and Ian (VTE)