Hi was checking my Range Rover 3.6 tdv8 this evening and the coolant was very low I screwed the top air was released and level came up about an inch still very low I added a liter of coolant to bring it up to between the 2 lines
I took car for a 40 minute drive checked again and it was below first mark opened cap and it went up about a cm still at the lower mark
My car is parked in garage with no visible leaks
What could it be --- I'll check level in the morning when car cools over night
Thanks in advance

How much is it losing ?

Are you sure there is no sign of a leak anywhere ?

In answer to what could it be - it could be a head gasket - but hopefully not as that's engine out & over 20 hours of labour......

You need to bleed the system properly. Procedure is in the workshop manual in the wiki. But basically you need to open the bleed valve when the engine is running and heater on max. Keep topping up until no air comes out of the bleed screw.

If you're not seeing and leaks then chances are the thermostat housing is the culprit. As it is between the banks coolant tends to evaporate before you notice it.

Bit of a pain because you have to remove quite a bit to get to it but the replacement isn't expensive. Ed

If you have an inspection camera and remove a couple of bits you might be able to see crusting around the oil cooler / filter.

Have a read through Edfors EGR valve replacement thread. Ed

Don't know how much it is using as only discovered low level
How many liters of coolant is in tdv8

I went out to garage and removed engine plastic cover shown torch down and I do see water around the bottom were the oil filter is

How much would the o ring cost to be replaced in the thermostat
Thanks

I think its somewhere between the 12 and 20 litre mark. Not sure but a surprising amount.

The o ring is pennies I think but I replaced the whole thermostat for about £120 I think. That included the elbow hoses on the side and the required o ring. Once I'd gone that far decided I'd replace the lot, takes a fair bit of time to remove enough to gain access.

Although I think you can do it without removing the EGRs so probably quite a bit simpler since the heat shields won't need to come off. Although might be worth checking if you have any faults relating to the EGRs, I did and it turned out they had a broken part internally.

The leaking Thermostat does seem to be a very common problem! THIS WRECKAGE

Strange when I went out to car this morning when cold the level was an inch under the mark when I unscrewed the cap air was released and level went up to correct level

Does anyone know a good Range Rover man in Belfast
Thanks

Pressure system... Ed

Mine was leaking at thermostat, did require EGRs off, annoying as they had been replaced just 2k miles before. EGR failure has killed two TDV8 engines locally, mine were showing occasional fault codes so were changed as a precaution at 75k miles.

The water leak on mine showed no dripping on drive only level dropping in expansion tank. 2016 RRS Autobiography, Gone in 2018 56 plate Vogue SE TDV8 - my first Land Rover since Disco 2. Other cars 2012 Boxster S, 2007 FL2, 1996 MX5 Gleneagles, kids Fiat 500 and Corsa. Recent now gone 2003 Subaru WRX Wagon PPP, Mk3.5 MX5, VW Tiguan, 997 Porsche Carerra 4S, Porsche Boxster S (old) and wife's 2007 Saab Wagon. Recently had Subaru Impreza STI PPP, various MX5s and RX8. RR is first grown up car for a while.

Thanks for info was it an expensive job
Thanks

Local LR specialist charged £600 plus VAT but that included supply and fit of a parking sensor on same bill, so I guess £450 ex VAT for the thermostat work - including replacement of thermostat housing itself.

The parts weren't expensive, Thermostat housing was £55, 4x hoses (changed at same time) £82, cooolant £20. Main issue was labour of 8 hours, which included the parking sensor. Most of the labour was the same as for the EGR valves, which were £900 inc VAT, supply and fit. Main dealer labour rate would probably double the total bill at least.

My LR specialist would advise changing EGRs having had the two TDV8 engines killed by bits of failed EGR falling into the engine. I think the EGR parts were around £600 of the total cost. 2016 RRS Autobiography, Gone in 2018 56 plate Vogue SE TDV8 - my first Land Rover since Disco 2. Other cars 2012 Boxster S, 2007 FL2, 1996 MX5 Gleneagles, kids Fiat 500 and Corsa. Recent now gone 2003 Subaru WRX Wagon PPP, Mk3.5 MX5, VW Tiguan, 997 Porsche Carerra 4S, Porsche Boxster S (old) and wife's 2007 Saab Wagon. Recently had Subaru Impreza STI PPP, various MX5s and RX8. RR is first grown up car for a while.

Thanks for info you all have been really helpful
Thanks I'll keep updated thanks

We had to change our thermostat housing at 65k as well, we were loosing coolant over 4ish months before reaching the low level. As above shine a torch down near the oil filter if you can see red gunk then thats leaking.