Coolant leak from oil filter!

This one has really got me confused so any suggestions would be welcome.

A few weeks ago I finally completed a full engine rebuild top and bottom ends with new Burton water pump conversion as last year’s rebuild was disrupted by a very premature water pump failure.

After the usual minor niggles I got the engine running and have to say that it it really flies with loads of power throughout the rev range. However, after a round trip of around 100 miles I noticed a worrying puddle of fresh coolant pooling under the engine. The radiator was, of course, down and upon checking underneath with the engine running a steady drip of clean coolant could be seen dripping off the oil filter seal (cannister type). I considered that it looked to be getting pushed out of the filter housing but after dropping the sump an finding no traces of water in the oil I decided it must be a leaking bottom hose which was chaffing the filter housing.
I therefore ordered one of those excellent Samco hoses from cliveyboy and fitted it over the weekend before replenishing with fresh coolant. Afetr a quick drive around the block, engine running perfectly, I got back home to find the same leak and this time I confirmed it to be leaking pure coolant, no trace of oil, between the rubber seal and the filter housing.
I have tried to apply some logic to this but haven’t managed to convince myself yet.
Am I right in assuming this is most likely a cylinder head gasket problem as the most likely point for water to enter the oilways? The head was skimmed by QED before refitting and appeared to be in good condition. If this were the case would there not be coolant in the sump when I dropped the oil and why does only water get extruded from the oil seal with no trace of oil whatsoever? I know oil and water don’t mix etc. but I thought there may have been some traces.
What is my best strategy to pin point the problem? Remove the cylinder head and look for signs of leakage? nothing exetrnal at the head gasket. Or do I get one of these leak down tester things or use a pressurised coolant tester?
I have not considered a leak from the block as this seems least likely and too depressing to contemplate but any observations, suggestions or previous experience of this phenomenom would be most welcome.

Regards,

Bob

Bob

You appear to have already summised that it is very unlikely for the coolant to get into the oilways and then leak out of the oil filter without contaminating the oil in the sump.

My only thoughts are that it must be leaking from elsewhere and just dripping onto the oil filter seal somewhere before dripping off the seal and onto the floor. My suggestion would be to pressurise the water system (not more than than 3-4 psi) with the engine not running and see if you can tell where the is coming from. The likely places are the cylinder head gasket or a core plug on the block. Also as you have a newly fitted water pump I would closely examine that.

Good luck
Andy

Look for the simple things first. :unamused: run your finger along the heater hose and especially around where it goes onto the spigot from the front cover- is the hose clip tight? My heater hose seems to touch the oil-pressure gauge pipe (or near enough), water running along the underside of this hose would run down the oil pipe to the filter housing.
Another possibility is a leak from where the front cover meets the front face of the block, water could run along the top of the protruding sump gasket to the filter housing (this is more unlikely of the two suggestions).

After I did my Burton pump job I got my knickers in a twist because there was a bit of Mayo under the oil filler cap- imagined all sorts of disasters until a guy on this forum told me he had exactly the same thing on an air-cooled Beetle after a winter re-build. That was just condensation and soon cleared.
Moral of story- don’t panic!

If it’s not a deluge, chuck some Radweld or Barr’s Leaks in and enjoy driving it! :smiling_imp:

Cheers,
Pete.

Does the Burton front cover have a drain hole for the water pump bearing like the original Lotus one ? If so, looks like you’ll be testing the ease of water pump removal… :wink:

:arrow_right: Matthew