The water pump weep hole sits in the narrow gap between the camshaft oil seal and the mechanical seal. The reason it is there is that if the mechanical seal fails and allows pressurised coolant to pass it will flow out the weep hole rather than being forced past the oil seal and into the engine crankcase. For a photo of how it all goes together see the infographic here.
The weep hole is located on the rear engine cover – the green wire is inserted into it below:
View without the wire:
First, clean up the camshaft hole in the rear cover – this particular one was quite messy:
After cleaning it out it looks as though there’s still some junk in the weep hole:
Using a thin piece of wire like the green one above (that particular one is a plastic sheathed wire used on electronic breadboards) make sure you can insert it the whole way through. Pushing it in from the outside resulted in this:
It helps to spray a bit of degreaser or similar through there to collect anything that the wire doesn’t. The wire inserted the whole way:
This particular weep hole was fully blocked. Sometimes a previous owner may mistakenly (or not so mistakenly…) block up the weep hole once they notice that it’s leaking coolant, or it could just be an accumulation of dirt or even dried coolant/oil/etc. from a previous leak.
If you’re doing this as part of the triple or quadruple bypass, click here to go back to the main page for that.