[Engine] Coolent loss

[chevyimp]

Hi my 2007 1.6hdi is losing coolent without any visible signs. Any known common faults I'm missing.? Does the coolent reservoir pressure cap fail? How would I check this?

[cancunia]

Welcome.

Is there any white foam in the oil filler cap, or white smoke from the exhaust?

[polar]

The water pump can leak - have you had it changed lately? Heater matrix can fail - the smell of curry in the cab?

You really need to get a pressure test done to find the leak.

[saskak]

In addition to the other suggestions, if you have removed the air intake pipes the bleeding screw (above coolant thermostat housing) might have been "disturbed" and leaking. The coolant thermostat housing gasket is fairly common to fail with age. There is also a small intercooler connected to the EGR that coolant flows through.

With these you should see some coolant leakage though.

[chevyimp]

Welcome.

Is there any white foam in the oil filler cap, or white smoke from the exhaust?

Thanks for the reply.. there's no foam or white smoke.. think I'll get a pressure test and report back

[chevyimp]

The water pump and leak - have you had it changed lately? Heater matrix can fail - the smell of curry in the cab?

You really need to get a pressure test done to find the leak.

Thanks for the advise.. I'm getting none of those symptoms.. I'll get a pressure test and report back..
What is curious though is that the levels seem fine for a day or so then I'll see maybe a 500ml loss in the reservoir..

[chevyimp]

In addition to the other suggestions, if you have removed the air intake pipes the bleeding screw (above coolant thermostat housing) might have been "disturbed" and leaking. The coolant thermostat housing gasket is fairly common to fail with age. There is also a small intercooler connected to the EGR that coolant flows through.

With these you should see some coolant leakage though.

Thanks for your suggestions I'll investigate over the next day or so.

[jj9]

If no external leaks are found check the EGR cooler.

It's possible for the EGR cooler to have an internal leak allowing coolant to leak into the intake system, if a sizeable leak the symptoms can be mistaken for a blown head gasket, (white smoke from exhaust) however if the leak is slight it can go unnoticed.

The EGR cooler may only leak when hot so pressure testing may not show it up, bypassing the cooler by linking the pipes would be one way to test it, if the coolant loss stops you've found the problem. 

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