I wonder if anyone can help me. I have a 67 Mark 2 340 which has developed a small coolant leak but I'm struggling (without access to ramps) to work out the source. My radiator was replaced with an aluminium rad a few months ago and, aside from a couple of leaks from hoses which needed tightening, I haven't had any further problems in that area. However, I now find coolant dripping from the bottom of the oil filter; I wonder if anyone has an educated guess as to where it's coming from. It's not a torrent but a drip every few seconds. I wonder if it's likely to get much worse and whether or not I should attempt to drive the car. I'm a bit of a novice; any advice would be much appreciated.

 

After a cold-soak, preferably overnight, put a pressure tester on the system up to about 1 bar and see if the pressure is dropping. You can then look for leaks with a torch and mirror under the inlet manifold to see where the leak is coming from.

 

+1 on pressure test

 

Thanks guys - unfortunately I don't have the pressure testing kit. Guess I'll have to take my chances and try and drive it to the jag doctor (we're not spoilt in London for specialist garages). I'm not sure if this is relevant but alongside my current issue I've been having difficulty in starting the car: sometimes I just get a click from the starter and when the motor does engage it's making quite a different noise (does seem to get the car started though). I wonder if the two problems might be related

 

Sounds like a dodgy starter or solenoid. Perhaps coolant has leaked onto the starter motor from above.

 

Check your battery connections running from the battery to the solenoid and to the starter.
There's also a small 12 volt wire that energizes the solenoid, but that sounds like it's working.

Also check you battery ground strap where it bolts onto the fire wall as well as your earth cable that grounds the block to the frame.
That cable is found down low underneath the generator, if not there, check the other side where the front motor mount is.

And yes, any coolant getting on the starter could cause a problem with its cable _ as NBcat said.

 

if it is not the cylinder head gasket, (hopefully NOT!!), it could be a Freeze Plug leaking, meaning you have to replace it.

if it is a Freeze plug leaking, it is a job for a professional to remove the old freeze plug and install a new one, but the removal is the dangerous part, if it falls inside the block while removing it, catastrophe.

 

Thanks for this. I can't see any obvious leaks from around the cylinder head and I'll check the oil cap later - presumably the oil will be milky or grey if it's got mixed in with the oil. Strangely, having been out for a half hour drive, the leak appears to have stopped - that would be great: a self healing Jag !

 

It could well be a core plug leaking, the heat expansion may allow it to seal, check the core plugs for signs of staining above the oil filter housing. You may need a mirror and a torch as the core plugs are below the inlet manifold.

If you have a head gasket leak to the outside it is unlikely to be mixing with the oil, generally the head gasket would go between waterway and cylinder (water in exhaust gas) between waterway and oilway (water mixed with oil) oil into cylinder (oil in exhaust gas) waterway to outside (leak externally) etc. it would be quite catastrophic gasket failure to go between waterway and oilway and also outside and you would probably have other symptoms.

Core plugs are pretty easy to change, they don't need huge skills, just take the correct approach and they are straight forward, and it is in my opinion almost impossible to lose one inside the engine, it most definitely won't fall inside the block. You have to punch a hole it the offending core plug (do not drill it) and you can lever the old plug out, clean up the seat, use some Hylomar sealant and install the new core plug, punch the center with a socket (there is a special tool too) this expands the core plug to form the seal and hold the plug in place.

 

Did you pressurise the system to check for leaks?

The system should hold 1 bar of pressure for at least fifteen minutes.

 

The OP does not have a pressure tester.

 

could also be a Heater Hose / Pipe, which in the 3.4 and 3.8 engines travels on the upper half of the engine, on the intake / carb side.

look at the 90 degree elbow between the engine and the battery, it is a source of coolant leaks there. Feel under the hose to see if there is coolant at the hose where it joins the steel pipe.

 

Did you find the leak source Sleddy?

 

Thanks Jon and sorry for not having replied sooner. I took it back to the garage who fitted the rad who told me a was a hose (on part of the engine that I couldn't get to without ramps) that was leaking. The leak is back though and there's another small leak from where a hose joins the bottom of the rad - deep joy. Could you recommend a specialist in the London area ?. All of the people I've tried thus far are bloody expensive and never seem to be able to actually fix anything - often claiming that the poor quality of replacement parts is the culprit. Any advice from you would be much appreciated. A

 

I could certainly tell you who _not_ to go to in London....

 

Actually, that would be terribly useful ! My e-mail address is sleddy@btopenworld.com Please do get in touch

 

I shall email you now