RHR engine coolant loss

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kelpiebat

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Coffs Harbour, NSW Australia
My '07 265k RHR engined man 407 and her '10 190k RHR 308 auto wagon both need coolant top up from time to time, say 6-10 k's. On the grounds that it is a closed system, I believe, topping up should not need to happen, but there are no signs of leaks. Is this normal or should I look more closely ? Have heard of some problems with EGRs.
Thanks for any thoughts etc.
 
Check water pump when engine cold. Typically weep when system not pressurised.

There is a hole under pulley at bottom.Look for green coolant, torch actually works better and look for drips on floor.

Assume you have pressurised and checked all usual places
 
There are the obvious things to look at - pump, bleeders, head outlet housing, radiator, etc..
If there is no clear external leakage, maybe suspect the heater core or the EGR heat exchanger, which will leak into the exhaust.
 
I've got an '06 307 HDi that's doing the same thing. Where is the EGR heat exchange and would you see any signs of coolant loss on it if it was the problem?
 
EGR2.jpg Back of the engine.

PS It will either leak onto the exhaust and evaporate; or leak internally into the exhaust gas recycling system and be turned to steam and eventually expelled into the tail pipe.
 
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Hi seasink, that looks like a rather difficult place to get to without removing the engine. I guess that if it is an internal leak it is a failed seal and there would most likely be an odd smell. Have at times noticed a strange smell on cold starts and idling before moving off.
The high pressure test the 308 passed was begun on a switched off running temp engine that slowly cooled. At the moment your suggestion is the only scenario that makes sense, and the only way to test for it would be with an engine that is running, though I've never heard of that being a common practice.
Thanks
 
Difficult of access in best French tradition, but not impossible. I was following up David S's suggestion of a leak in the heat exchanger. It is made from thinnish steel welded up, with very hot gas on one side of the internal passage and water on the other. Corrosion somewhere is always a possibility.
 
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