3.Oi M54 coolant leak - belt spray - cause?

[JSz4]

I noticed the coolant in my 2003 3.0i was dropping in June and spotted damp on the undertray and dried white spray on the side of the airbox

Garage confirmed water pump leak so replaced it with a £53 Airtex one and it seemed fine since.

However checked coolant today, it is on minimum level and see again dried white spray on the side of the airbox:

https://www.dropbox.com/scl/fi/kq4zslzzr5c3hwhrv7cgg/IMG_2852-1.jpg

I had the thermostat housing and expansion tank replaced in 2018 (35k miles ago) due to leaks. Any ideas where this new leak could be coming from, has the new pump likely failed or could the new leak be from anywhere else dripping on to belts?

Thanks for any advice

 

[enuff_zed]

Check the hose from the expansion tank to the top of the engine. Wife’s car had same symptoms and it turned out the seal in the engine end had failed. The pipe was free to wobble about. Water seeped out, ran down the pipe and dropped onto the belt.

 

[patriot66]

Also check the green o-ring on the coolant temperature sender in the bottom hose where it connects to the thermostat. A bit awkward to get at but a drip can run down and look like the hose connection itself is leaking or worsen and then be blown around by the electric fan or auxiliary belt

 

[JSz4]

Thanks both, I had a look at the pipe from the expansion tank to engine and there's not much movement, I'll have a look at the coolant temperature sensor tomorrow. Thought I'd replaced everything that could leak already!!

 

[colb]

Recently found a pin hole in the plastic side of the radiator on a 3.0l just at the top by the top hose area, only leaked when car up to temp. New radiator required to fix the issue. Usually the expansion/filler tank is the cause when that develops cracks or pin holes in the plastic sides. First time I have seen this issue with a radiator.