Hi all,

I have a Mazda BT50 2009 2.5Lt 5 speed manual 4x2 with the WL-C engine in her. This have been a mystery for me as I am unable to find the issue where the coolant is going. Ok so let us start from the beginning I had noticed a wet patch at the back of the block going onto the gearbox, I had wiped it one day and then the next it had appeared again. At this time, I was checking the water level and noticed that there was a sludge around the radiator cap as you can see in the picture to me it looked like oil in with the coolant. I asked my brother-in-law, and he told me that it was a blown head gasket, so I had ordered a new one and replaced it the head not warped at the time of removal. So, as I have been driving it around again, I had noticed that the water is still escaping but there are no leaks on the floor or any evidence on the engine. So now I have done a compression test with it dry and with a bit of oil down the cylinders as you will see the compression is fine then I did a coolant leak test on the engine as per to the manual and it's fine like in the photos I left it 5min. The car runs great no lag good pickup I am in needing of good advice if anyone has had the same or similar issue with their BT50.
Here is the pressure before the 5min test

Here is the pressure after the 5min test

Here is the oil sludge that I had found in my coolant

 

Common for the EGR cooler to leak internally.

 

Hi grim_reaper

I did forget to mention that the EGR has been disabled and bypassed but the issue is still happening.

Thanks for the heads up