[agreiguk]

Hey All,

wits end here. I have an M62 4.4v8 that’s losing coolant with a strong smell of coolant when it warms up. Ive pressure tested from the expansion to 1.5bar and no loss over three mins. What would you all advise as next steps. I’m planning on flushing it and filling fresh but I’m mindful I’m just gonna lose all my new coolant eventually. No signs of leaking water when left parked up. Some have suggested remove the rad shroud and run it.

Would i I be right in thinking that a pressure test only tests the expansion and upper hoses but nothing the other side of the thermostat as it’ll be closed.

thanks all

alan

 

[Wayne Tj]

I don’t believe that the thermostat will impact the pressure test, as it only restricts or opens the flow of coolant. There is a small hole that will allow pressure to equalize on both sides of the thermostat.

 

[Mrmerlin]

BMW M62 engines have a few cooling leak areas,
the Valley pan seal this is easy to spot with a good flashlight look along the intake manifold mating areas for coolant puddles.
the rear water bridge gaskets one on each rear cylinder head, these are harder to see as they are at the rear of each cylinder head and swapping them also moves the pipes and O rings in the water pump.

the short hose from the water bridge to the firewall, this is a common fail part the dealer should have these in stock,

the expansion tank these seem to crack whenever they want.
The radiator plugging up the last 6 rows then the side tank cracking, Radiators should be checked for plugging and or swapped out every 100K miles or so
tell tales are found at the edges of the swages you will see white crusty deposits going down the tank then you have a leaker.

NOTE you can also swap in the M60 diesel thermostat might be easier to find where you live. this will let the engine run a bit cooler and thus all of the other parts of the drive line will also last longer

 

[brad s1]

My rule of thumb with that motor is once it's got some decent miles and it begins leaking... replace everything coolant hose related. Or just sell it because it'll always be an issue.