Coolant leak

[rogerotto66s]

My ‘66 “S” has developed a coolant leak.
Leak occurs only when engine is running.

Hoses appear to be OK.
I tried using an endoscope to view the hard to view areas but could not find a source.

What are most likely sources?
What am I missing?

[LarryLebel]

Probably the water pump.

[mk1]

Have you managed to determine what end of the engine the water is coming from? I reckon the pump is a good place to start, but without further info it's just a guess.

[Fanfaniracing]

I recently had a similar issue with having some drops on the floor where the Mini was parked.

Found out that it was the water plug on the rear of the Block who was leaking...

[rogerotto66s]

Probably the water pump.

How does the pump itself leak?

Is it through the gasket?

Are there other symptoms for a bad pump?

[rogerotto66s]

Have you managed to determine what end of the engine the water is coming from? I reckon the pump is a good place to start, but without further info it's just a guess.

From underneath the car the coolant runs down from above and drips off the gearbox.

[Peter Laidler]

Most common pump leak is through the shaft seal Roger. A leaking seal isn't always accompanied by knackered bearings so rocking the fan blade or pulley isn't necessarily indicative of a knackered seal.

[surfblue63]

Could it be the by-pass hose?

[rogerotto66s]

Could it be the by-pass hose?

Bypass hose is new and looks good.
I was able to view using endoscope.
Thanks

[rogerotto66s]

Most common pump leak is through the shaft seal Roger.

Would I then expect to see the coolant dripping from the radiator side of the water pump pulley.


Just read something about coolant leaking from the “weep hole” when seals or bearings are going bad.

My water pump (which may be original to the car) has a screw in the weep hole.
Can anyone explain this?

649C36B1-4D1E-464A-AF3B-FF418444FBA8.jpeg

[woodypup59]

The screw is for a grease nipple, the weep hole is underneath the pump body.

If the gland is leaking you may see drips inside the yellow pulley.

Are you sure the heater circuit is fully bled of air ?

Have you spread clean paper under the engine, whilst running perhaps, to see the general location of the leak ?

Also, check you're not overfilling it. I've always found that if you fill up to the "bar" inside the radiator neck, the engine always spits some water out of the breather to get to its own, desired level.

[AndyPen]

That's a lubricating hole and only on the old pumps. The 'leak' hole is the one on the underside Rog

Edit to say I didn't realise it had been answered on another page

[rogerotto66s]

The screw is for a grease nipple, the weep hole is underneath the pump body.

If the gland is leaking you may see drips inside the yellow pulley.

Also, check you're not overfilling it. I've always found that if you fill up to the "bar" inside the radiator neck, the engine always spits some water out of the breather to get to its own, desired level.

Thanks for the feedback re: grease nipple vs weep hole.

I see no coolant inside the yellow pulley ... this is a good thing.

Just pulled the radiator cap and took this picture.
Looks like you were correct. The unneeded coolant was “evacuated” (I assume via the overflow hole/hose).
I guess I never saw the horizontal bar containing the words “water level” and I was just overfilling the radiator!

Hopefully I really do not have a problem !
I was not looking forward to replacing the water pump!

I will update this topic as required.

D5596AC4-7BCF-452E-989C-496B8B309667.jpeg

[Peter Laidler]

Just to answer the question about the coolant leak via a worn shaft seal. The leaky fluid just gets thrown out by centrifuge so not immediately noticeable on the inside of the fan blade cup.

The good thing about your topics Roger is that you always keep us up to date with no loose ends afterwards!

[rogerotto66s]

Sorry to report my problem is not due to overfilling the radiator.
Had it out for a test drive and the leak persists.
I will need to put the car back up on jack stands to be able to check from underneath.
Temperature gauge was reading “N” at the time of the leak.