Practically Classics Forum

After a few years sitting dormant in my garage with a catastrophic engine failure I bought a replacement second hand engine for my BMW E34 520i. I plumped for the cheapest at £225 and got it fitted and MOT'd for a total outlay of £500 including the engine price so was well pleased. It has worked hard since and has dragged my sons speedway bike round the country for the last couple of years with no problems but it was using a 1/2 a litre of water per 300 odd miles and about a litre of oil per 750 miles.
There was no sign of water in the oil or oil in the cooling system so I didn't worry too much and temp. was allways normal.
After one long trip the tappets started clattering loudly so my mechanic changed the oil and said there was steam coming off the old oil, a good indication that water was getting into the oil.
On his advice I treated the cooling system with K seal and it has not used a drop of water or oil since. I am curious as to what the fault was. I could understand it curing the water leak but why has it stopped using oil? If the leak was between the cooling system and an oilway surely there would have been signs of oil in the cooling sytem with the amount of oil it had been using. Any thoughts?

Water under pressure can force its' way through small cracks or flaws in a gasket, whereas the oil is not under the same pressure. Once an engine is turned off the water takes a long time to cool and so lose pressure, but the oil stops circulating immediately. You can therefore get water entering the oilways without any return flow. The oil consumption may just be through natural usage because of wear.

TriumphDriver wrote:Water under pressure can force its' way through small cracks or flaws in a gasket, whereas the oil is not under the same pressure.

Oil pressure is normally far greater than coolant pressure, (or should be) so oil under normal running conditions can easily force its way through small cracks and flaws in the same way coolant can. Blocks and heads can be porous, especially after rebores. I had exactly the same problem on a recon short motor I fitted, to which I added a sealant, and had no further problems.

Thanks guys, I guess my confusion was where the oil was going. The exhaust was allways clean and only a few spots on the drive. With the amount it was using I would have expected it to be evident somewhere. Maybe water getting into the oil was causing it to burn easier?
Still all seems well now and for around £500 I got an old car back on the road which has served me well for the last two and half years. Some friends who said I was mad wasting money on it pay more than that for a service on their new cars!
How long the K seal repair lasts remains to be seen but I have certainly been impressed so far and it's been in for about 4 months now. Has anyone else had experience with it over a longer period of time?

Hi well not me personally but my son has a BX 16Valve that blew a head gasket while a long way from home, as a temporary measure used K seal as a 'get you home' measure. He was going to replace the gasket etc. as he has the bits to do it, but time in short supply so thought that he would see how long it would last, that was 2 years ago and it's still fine.
A friend of mine has an old Leyland Sherpa van and he had a "touch" with a sticky out object on a farm, the radiator crumpled a bit and because it was paper thin leaked quite a lot, I always carry a bottle of K seal and this cured it enough for him to drive home some twenty miles and then enough to get another radiator.
It seems to work, must get a replacement to carry.
Cheers.
Geoff.

I should point out that this stuff will destroy carbon water pump seals so if you own a Saab 99, Dolomite, TR7, Stag or any of the kit cars that share the engine with those, then don't use K-seal or the water pump will then allow the coolant to drop straight into the sump.

Hello John thank you very much for that invaluable information. May be should be printed in RED and put somewhere highly visible.
Cheers.
Geoff.