Thread: Slow coolant leak

Originally Posted by DiscoJeffster

I seem to have one. Losing coolant slowly over time. I can smell it when the engine is turned off but I can’t see the telltale signs anywhere. Losing around high to low on the bottle over a month or two.

I was thinking egr but then I’d not thought I’d smell it. I previously replaced the crossover when that bleed failed so it’s not that.

No drips, obvious leaks.

I guess I need to take it in and get a pressure test done.

Have a look passenger side next to the turbo through the wheel arch.

Originally Posted by shack

Have a look passenger side next to the turbo through the wheel arch.

That leak will be visible on top of the AC compressor, Check your radiator cap and bottle. My aftermarket cap was leaking and caused the same issue. I've got a new genuine bottle and cap to go on. I pressure tested it and it held over a weekend

Check also plastic bleed screw on crossover pipe at back of motor.

Originally Posted by josh.huber

That leak will be visible on top of the AC compressor, Check your radiator cap and bottle. My aftermarket cap was leaking and caused the same issue. I've got a new genuine bottle and cap to go on. I pressure tested it and it held over a weekend

Bottle isn’t leaking. Genuine cap. Leaks there are obvious as the coolant leaves a lovely trail.

Originally Posted by PerthDisco

Check also plastic bleed screw on crossover pipe at back of motor.

As per original post, coolant crossover is new and bleed screw new after previous failure. Thanks anyhow

The vacuum fill kit I bought comes with a manual pressure tester also, you're welcome to come and grab it if it'd help.

My experience with pressure tests is it's often much easier if the cooling system is empty. Then you can run around with a bit of pipe in your ear and the other end scouting around looking for the leak (listen for the whistle).

When I had the slow leak in the D3, it was a pinhole in the EGR cooler supply hose right under the intake elbow. It took quite a while under pressure and looking around with a torch and borescope to spot the spray.

Thanks Brad. As a groper (sandgroper for those who think I’m inappropriate) I might take you up on it. I’ll wait until coolant comes on special and do it all at once. New Meyle bottle in the garage ready to go.

I’ve also got a coolant smell and a very slow drop in coolant level on mine. Nothing obvious from above or below, but it started after I had the timing belts replaced. So in my case I suspect a small weep from the coolant manifold ‘O’ into the head, I replaced the coolant manifold (Including the ‘O’ ring) 6-12 months before the belts were replaced.