D4 Coolant Leak, No Visible leak or in Oil! HELP!

I've had to do head gaskets twice now , one on RRS 2.7, the other D4 , both neglected, both hadn't replaced the coolant bottle when they inevitably fail so hadn't heeded the warning when the top coolant outlet ( also inevitably ) let go .
Both had warped the heads in the middle letting combustion gas into cooling system ( and vice versa ), with one having to replace heads as they were too far gone.

With system full and bled , take it for a 5 minute drive then check by hand if the hoses have pressure, if so there is a very good chance the heads have warped.

Being an engine with lots of plastic components there might be a fair bit more to replace depending on how hot it got.

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Originally Posted by Eric SDV6SE

what the others said, if engine runs without irregularities, then unlikely to be head gaskets. Also no coolant in oil or oil in coolant, so all seals around oil cooler would appear to be ok.

get a second or third opinion. Engine swap is way too drastic imho.

look for staining at cross over pipe over back of engine, coolant can leak from the plastic cap there and evap before reaching anywhere to pool.

Bleed the coolant system properly via the little tail hose near the main radiator hose.

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We checked the cross over pipe and the plastic cap, both are fine.

The bleeding was done via the tail house, too.

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Originally Posted by BrendanSwift

We checked the cross over pipe and the plastic cap, both are fine.

The bleeding was done via the tail house, too.

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There are three bleed points. One at the rear on the crossover pipe, one near the coolant outlet on the V, and one at the bottle. If you didn’t bleed using all three, then it wouldn’t surprise me if it’s still bleeding out air

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Originally Posted by DiscoJeffster

There are three bleed points. One at the rear on the crossover pipe, one near the coolant outlet on the V, and one at the bottle. If you didn’t bleed using all three, then it wouldn’t surprise me if it’s still bleeding out air

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Thanks mate! I forgot to mention it, we did bleed from all three locations :(

Have you got rear aircon?

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Originally Posted by RavenD

My D4 (2010 3.0 SDV6 166k) had a Low Coolant warning, after over heating and few other crazy warnings (Gearbox fault, Engine oil monitor system fault, Stability control not available drive with care, Emergency brake not available) we towed it to the repairer.

Since then, replaced the coolant tower and tank, reset the faults. All are gone and didn't come back. BUT after running the engine for about 30mins we can see coolant level start to drop and the Low Coolant warning comes back on.

Thermostat is working. Not leaking coolant from the EGR valves. No coolant in the engine oil. No visible leaks or drips from the engine. Can't be 100% sure if there is coolant in the exhaust, the Carbon Monoxide readings are not conclusive.

Repairer's suggestion is to put in a new engine suspecting a head gasket issue when the engine over heated. This will cost a pretty penny! $$$$!

Any suggestions, ideas before we go down this path?

Cheers!

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UPDATE
They have swapped out the EGR valves with secondhand ones to get it up and running again and have done two 30km trips and vehicle is holding the coolant. Though in the initial inspections, they couldn't find any major leaks there, they suspected there could have been a small leak.

Will get the car tomorrow and run it for a couple of weeks to see how it goes.

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Originally Posted by Tombie

Have you got rear aircon?

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Yeah, mate, we do. Any possible leakages in that area?

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Originally Posted by BrendanSwift

Yeah, mate, we do. Any possible leakages in that area?

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Can hold air. Makes bleeding fun.

You need the rear on full heat, nose parked up a decent hill and engine warming up. Then start bleeding.

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Originally Posted by Tombie

Can hold air. Makes bleeding fun.

You need the rear on full heat, nose parked up a decent hill and engine warming up. Then start bleeding.

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In UK many cars with rear air con have suffered corrosion damage to pipe work under car and lost fluid so maybe check for damage.

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Originally Posted by BrendanSwift

UPDATE
They have swapped out the EGR valves with secondhand ones to get it up and running again and have done two 30km trips and vehicle is holding the coolant. Though in the initial inspections, they couldn't find any major leaks there, they suspected there could have been a small leak.

Will get the car tomorrow and run it for a couple of weeks to see how it goes.

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I only remember now you have posted above, my D3 had EGR leaking issues that initially was thought then dismissed (as they rarely do head gaskets) to be potentially head gaskets. The cooling was remove and problem resolved. So, you may be in the clear. Hope so....