Hi all. First time posting! I need your combined diagnostic skills...
I found a large amount of oil in my coolant reservoir! However, I cannot find any trace of water in the oil. I have drained the engine and gearbox oil, both of which look good. When stripping the auxiliary fittings off the head to get to the engine oil cooler, I have found only crystal clear coolant. I've replaced the gearbox oil cooler as it was pretty cheap, but have suspected the engine oil cooler to be the problem based on my findings on this site. Now that I have taken the engine oil cooler (and filter assembly) off the block, I see only clear oil. I know that the oil pressure is higher than the water pressure so the oil will move towards the oil if there are any leaks. I also don't believe that my lungs are strong enough to blow into the water pipes of the cooler to listen for a leak! The only spare engine oil cooler in my area is from Land Rover themselves at a Land Rover price The engine has never over-heated, has been perfect until now, and for the past year, has not driven more than 75km in a single trip. Any ideas for me?

I agree that sounds more like oil cooler than head gasket but head gasket is a possibility too... depending on where the leak is that might be a one way oil=> coolant leak.

Any sign of unusual moisture at the tailpipe? It will normally drip a little plain water after startup and then should be dry after warm up.

I'd probably just replace the oil cooler and see what happens... that cooler, like the radiator, won't last forever anyway

Last edited by merlinj79 on 19th Jul 2021 3:59 pm. Edited 1 time in total

Hard to test now as the front of the car is in pieces. I have never noticed any dripping from the pipes. Just before I tackled this job, I parked the car, got my GF to stand behind while I revved the engine. There was no smoke or liquid, she said just clear air. I'm open to any suggestions before I move my focus to the head.

Could the Auto Transmission Oil Cooler be dumping transmission oil into coolent water?

It looks to me as if hot climate cars still have the standard oil/water cooler, plus the additional oil/air cooler. FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 76k+ miles) (MY2015)

I've replaced the transmission oil cooler (the local shop sold me one when I asked for an engine oil cooler). The engine oil cooler came out yesterday. Here's a pic before I pulled it out. Notice the lack of oil in the thermostat housing. I would have expected to see evidence of oil there given the amount of oil in the coolant reservoir.

Engine oil cooler before being taken out.

see link below

https://www.freel2.com/forum/topic34430.html

I had remembered someone saying that on modern cars it was worth trying the oil coolers before attacking the head gasket.

Otherwise the historic cause of water/oil mix was head gasket (if you were lucky) or head cracks or warping (if not)

Have you been having to top up coolant recently? That is a symptom that I associtate with head gaskets. FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 76k+ miles) (MY2015)

I haven't had to top up the coolant for about a year, probably more. It simply has not lost any water whatsoever. The more I read, and the more advice I am receiving on this forum, the more convinced I am that the problem lies in the engine oil cooler. The oil in the reservoir was brown, ruling out transmission oil.

Update: new generic gearbox oil cooler, new OEM LR oil cooler. Put everything back together. Flushed the water system once (anticipating doing it again). Took the car for a 35km drive now, and the reservoir is full of brand new expensive engine oil! I can't think of what other route to take besides the head. Still no water in the oil. Any ideas?

Sure it's not residual oil? Try flushing again? Carefully note both coolant and oil levels when cold and hot for future reference.

I forgot to mention that the water is disappearing rapidly: about 20km from full to 'low coolant' warning. The amount of oil and the clarity of the oil in the coolant reservoir leads me to believe that it's the new clean all that I have just put in. However, the level on the dipstick appears have stayed the same. I'll flush the system tomorrow, mark the current oil level on the dipstick, and take a drive. Then I'll check the oil level after. The rate at which the coolant is dropping has me pretty worried.

Its starting to look like you are blowing hot gases into the cooling system.

Internal Head Gasket failure? FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 76k+ miles) (MY2015)

GarethC wrote:

Hi all. First time posting! I need your combined diagnostic skills...
I found a large amount of oil in my coolant reservoir! ?

IanMetro wrote:

Its starting to look like you are blowing hot gases into the cooling system.

Internal Head Gasket failure?

Hi p_gill ianmetro, and merlinj79. My engine bay looks NOTHING like that, however that mess was completely contained in the reservoir tank, when I initially found the problem.
Yesterday, the local mechanic pressure-checked the coolant system and we found an obvious leak which appeared to be external of the head/block, somewhere around the new oil cooler. So I'm hoping to find that the disappearing water (subsequent to the change of the oil cooler) is simply a loose hose clamp which I missed in my excitement to put the car back together! We'll find out today when I tackle it.
The mechanic also feels that the oil which is showing up in the reservoir tank is simply the old oil which loosened up after the 30km drive I took on Sunday. He said that the last vehicle on which he replaced an oil cooler required 7 or 8 flushes to clear it up. The oil level hasn't dropped noticeably on the dipstick.
I don't see any excess smoke of any color out the tailpipes, and the engine and gearbox are now smoother than they have ever been.
Today, I'll find the leak, fix it, flush the system again, and go for a drive this evening. I'll update here after that.
Thanks for all the advice so far.