Has anyone experienced this leak from this hose? If so how did you fix it? It seems that the o ring requires replacing. Is there any chance I could purchase it or I will have to buy the whole hose? Does anyone know the part number. Maybe just the push fit connector?
Many thanks.

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2.5x18mm Viton o-rings have been used at the coolant fitting at the oil cooler which might also be suitable for that connector if the housing ID is close to 18mm.

Thanks GraemeS. I believe thats the right size 18mm. Thats what it says on the connector NW 18-30.
I will need to have a look as i remember I purchased some o rings for the oil leak I had from the back of the engine- the turbo pipe coming out from the oil cooler but I think these were different size.
I might just have to get buy those one and give it a try.
Once again many thanks.

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Or the inscription actually tells me the size is 30mmx18mm Viton o-rings ?

That would have to be 18 x 3.0 if it is the o-ring size.

I have a couple of 18 x 2.5 but might also get a couple of 18 x 3.0 to have in the spares box.

These pipes are not too expensive from main dealer.

Kind of on the same subject, could someone show me an engine diagram with the common leaks circled on the 4.4 TDV8? Mine loses about 100ml every 4,000 miles and in my searching around the engine so far, I haven't spotted anything pink yet, including around the thermostat housing and oil cooler. 2015 Range Rover Autobiography 4.4 SDV8

I have a small leak on the fitting on top of the thermostat housing.
Like a push fit connector. I think you have to buy the complete unit to get that pipe.
When I need to remove intake manifold I will replace.

The thermostat housing doesn't look overly different to the one on the 3.6 TDV8 which is one I've replaced before. Not an overly difficult job - just requires some persuasion to get the lower seal free on the unit and I found it easier to cut the 2x hoses going to the heads and replace with new than fanny around trying to get them off gently. 2015 Range Rover Autobiography 4.4 SDV8

It’s just the push fit pipe on the top. But need to buy complete unit to get that pipe.

garyRR wrote:

Kind of on the same subject, could someone show me an engine diagram with the common leaks circled on the 4.4 TDV8? Mine loses about 100ml every 4,000 miles and in my searching around the engine so far, I haven't spotted anything pink yet, including around the thermostat housing and oil cooler.

Not sure a pressure test would help, as I already know there's a small leak somewhere and just need to find it. It's of no urgency - would just be good to get some hints at other things to look at which are common on the 4.4 TDV8.

(Smoke test passed before anyone suggests) 2015 Range Rover Autobiography 4.4 SDV8

A pressure test would pressurise the cooling system with the engine cold and switched off so you could look for leaks.

It's a good way of doing it as you can rummage around safely without the fan or anything running and will also stop the air moving from the fan blowing the coolant from the source of the leak. 2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2007 Range Rover Supercharged in Java Black with Ivory Leather
2012 Range Rover 5.0 SC Autobiography in Indus Silver with Jet/Ivory Interior
2012 Range Rover 4.4 TDV8 Autobiography in Baltic Blue with Sand Interior

I bet it's an O ring somewhere. I'm convinced mine is doing the same but no obvious leaks...
I looked into buying a coolant pressure tester. Less than £100...
Workshop manual has a section on Cooling and pressure testing:

Using the correct adaptor connect the cooling system pressure test kit to the vehicle expansion tank.
Slowly pressurize the cooling system until the pressure gauge reads 1.0 bar (15 psi).
Make sure the cooling system holds pressure for 5 minutes, note that a small pressure decay of approximately 0.15 bar (1 psi)
over the first minute is normal. 2011 4.4 TDV8 Vogue SE Buckingham Blue with Ivory and clear glass = "Rory"
New Defender D300 90 on order so "Rory" will be going to a new home....!
1974 Series 3 Lightweight = "Millie"
My preferred specialist: www.glenrands.co.uk
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For you guys thinking of doing a pressure test, I had an old expansion cap that I managed to take apart and fixed a small tube in the centre. I connected it to my compressor and instantly saw where my leak was. A cheap idea for you handy folk.