Leaking coolant

[Traveler]

I am now beyond understanding on Repulse. It is a ZD30.

It is fitted with EGT so I can confirm a history without overheating. Also had the sump of recently and there was no sign of sludge, also had the intercooler cleaned during this time (no sludge there either). Also the alternator, starter and waterpump all replaced very recently.

Vehicle has a complete service history, and all seem well apart from a jockey pulley that needs replacing.

But my current frustration is leak of coolant. We have done pressure tests, carbon tests; you name it. But each morning there is a couple of ml of coolant on the garage floor. It does not leak at all when warm, it needs to cool down for the leak to show itself. We have refitted the waterpump also. Dealers and mechanics thinks that I am off my rocker complaining about a leak they cannot find.

Any ideas?

[Tinus lotz]

Do pressure test when cold

[Herrie]

Maybe it is the heaters radiator that is leaking. The pressure increase when the engine is shut down till the temperature goes down.

[Peter Connan]

Heinrich, where is the spot?

You should be able to see the anti-freeze trail, and it might even be worth it to add some anti-freeze for a short period in order to make the track clearer?

[Kalahari Safari]

I had a tiny hole in one of the water pipes possibly coming from a bite of an animal straying into then engine compartment.
It was not easily visible but every day some water was missing. Stumbled on it by accident when the engine started overheating on an overland trip and there was very little water left in the system. By filling up I saw some steam coming from a point where there shouldn't be steam and that was it.
Cut the (secondary) hose back a bit and re-clamped.
Check all the water hose clamps including the heater's it might help.

Another lead could be a seal that is hardened and cracked but that would leave traces of coolant (oxidized) and would become visible sooner or later.

[Traveler]

Herrie, I think you are on the right trail.

Thanks everybody, I am tracking coolant all the time Peter, that is also how we found a less than ideal waterpump.

[DawidT]

I had a similar problem on my GQ. the pipe underneath the intake manifold had a very small leak and the water squirting out when under pressure hit the warm block and evaporated before dripping on the floor. It is very difficult to see underneath the intake manifold and to see any trace of coolant. It popped on me close to Kubu Island.Only saw it when I put water in and heard a sissing noise and eventually saw the steam. Some advise....take ten days leave, load all da lekker camping stuff (and various sizes of water hoses and clamps ) head of to Kubu, viola, it will show on the pans The leaks has shown itself, you got the spares and to top it all..... a nice Bots holiday

Hope you find it soon.

[Traveler]

That is really good advice.