Hi Guys,

I'm new to this forum so please excuse me if this topic has been discussed else where. I'm having issues with a range rover L405 with the SDV8 having constant oil leaks, Last year, we noticed our car was having a oil leak from the back of the engine, research indicated that the leak was either from the oil turbo feed lines or from the oil cooler. Me and my dad changed both of the oil cooler gaskets and the O-rings on the turbo feedlines and we tested the engine afterwards with no issues or leaks, My dad's a Heavy Diesel Mechanic so he was able to show me how to do it and we followed the manual.

Jump forward a few months and we found the car was leaking oil again, upon inspection, we found the oil cooler gasket to be leaking again. My dad was unavailable for the reassembly of the cooler so I replaced the oil cooler gasket with some assistants from a friend who does a lot of mechanical work. We did it the same way as before, only difference is we used genuine land rover gaskets with a light coating of aviation gasket sealer and we placed it very carefully to ensure we didn't pinch the gasket.

A few days later it was still leaking, this was my fault as I didn't replace the turbo feedline O-rings when doing the gaskets as this is where the leak was. At the same time, I checked the oil cooler while I was there and there was no signs of any oil leaks around both the oil cooler gaskets. After replacing the O-rings with caterpillar Viton O-rings, we checked it a few days later, no oil leaks so we thought we solved it.

Jump a few weeks later and the Oil leak is back in the same place, I haven't found out which is leaking yet but I suspect the oil cooler gasket is to blame as the Turbo feedline with cat O-rings was a very firm fit. And the coolant warning light had just started turning on and off for low coolant.

I'm under the impression there's not suppose to be any pressure in that part of the engine, if there was pressure it would be crankcase pressure. We haven't got any other warning signs though I know the cars done 125,000km and the DPF has never been cleaned in the 5 years we have owned it but there's no warnings when its regenerating or full. Also that when we took the Oil cooler off, the oil cooler was slightly warped where the oil cooler meets the housing. Apart from this, I can't really think of anything else that would cause constant oil leaks oil leak from this one spot.

I'm wondering if anyone else has had this same issue or would be able to advise on other areas I should check for problems.

Thank You

Did you put a new oil cooler in? They often warp apparently (like yours).

Hi Richie,

No we didn't, is it know to cause repetitive oil leaks? because it did stop leaking for a few weeks. We did do the bolts that hold it down to the same torque as the bolts holding the main assembly down as there's no torque specified in the manual.

Thank You

Its not unreasonable to find that new gaskets on a warped housing prevent leaks for a short while until they have been heated a few times.

Yeah, you definitely should change the cooler. Mine leaked a few months ago and I changed the cooler. Job done 👍

Same here, had the usual oil leak from the oil cooler and was recommended to replace the oil cooler as there are very susceptible to warping and even cracking so for a few hundred pounds (OE approx £450 but good after market ones can be bought for a couple of hundred) I replaced the whole lot, job done, should not need to worry about again for quite a few miles.  _______________________________________________

2019 4.4 V8 Diesel Range Rover Autobiography, Byron Blue

Hey Guys,

Thank you for the advice, we decided to buy a new Genuine oil cooler assembly and I'll fit it once it arrives, ill probably replace some of the plastic coolant lines as well when I do the work as 9 years in Australian heat, there probably brittle enough they would crack from touching them.

I don't know if anyone has posted this on the forum but ill mark the bolts and crack the bolts loose holding the oil cooler down on the new unit and re tighten them with a torque wrench until the marker lines line back up and upload the torque's I get onto the forum as this spec is missing in the repair manual.

Is this what you mean, the torque for the oil cooler bolts? 13nm according to the workshop manual in the forum Wiki.

No, the bolts holding the oil cooler to the casting, see the image below, there's 6 of them but you can only really see 3 of them and in the manual there no torque setting for them. There probably 13NM but ill check it once I get the new unit as I haven't seen anyone post the torques on the forum anywhere though I could have missed it somewhere.

[/img]https://www.fullfatrr.com/gallery/albums/userpics/28115/thumb_OIL%20COOLER.jpg

You shouldn't need to touch those bolts if fitting a new oil cooler assembly as they hold the 2 halves of the oil cooler together. The other bolts hold the complete oil cooler assembly to the EGR cooler.

One of my expected advantages of having EGR mapped-out is that the EGR cooler no longer gets hot from exhaust gases and therefore the oil cooler gaskets should survive better.

Ah, I can’t see the image you posted (on my mobile) but I think you’re referring to the cooler part of the combined oil filter/cooler assembly. As far as I’m aware the replacement ‘oil cooler’ only comes as a complete cooler and filter assembly I.e the cooler part isn’t available separately.

I bought one recently (was part no LR022895, latest is LR113200). I received the complete filter/cooler assembly as per the Worksop manual picture above.

Hi Guys,

I need some help or advise, we recently had a new oil cooler assembly and gaskets installed on our Range Rover SDV8, all genuine parts, we have only driven it 3 times over the course of 5 days, and the oil and coolant leak are back. I'm not understanding what is going on as these a new gaskets (with aviation gasket sealer), a new genuine oil cooler and its still leaking. All surfaces were thoroughly cleaned before the gaskets were placed and the gasket was carefully placed on the engine ensuring it was sealed correctly (no gaskets pinched or loose from the housing when flipped over) and the correct torque was applied to the bolts in small increments making my way up to 13nm and the leak is back.

Can you guys think of anything else that could be causing the issue as the oil cooler is new and the workshop repair instructions were followed correctly.

Also, I tested the factory installed bolts that mount the oil cooler to the casting on the new unit and there done to 13nm.

Thank you

Interesting, I have a very small oil leak, have replaced the oil cooler and O rings but a slight oil leak is still occuring. I am unsure where the leak is but have an idea it isn't from the oil cooler. Leak is about 200 mls between oil changes, so no big deal but annoys me. I aim to clean down the valley area and get the borescope in and see if is infact a leak from the oil cooler. My son in law who fitted my last set of O rings seemed to think the leak is from the Drivers side rear , but I have checked Tappet cover and seems no leak from there.

So the search goes on.

Hey guys,

I did eventually find and fix the oil leak, the issue was something I didn't even consider but the heat exchanger was bent. It was only slightly bent but was enough that you couldn't get a good enough seal. We ended up replacing the whole heat exchanger assembly, I also pulled the assembly apart and applied a small amount of aviation liquid gasket to the rubber to help it seal better and now the oil and coolant leaks are gone. I did also check the torque specs for the bolts holding the heat exchanger down to the cast part (one with the oil filter thread in it) when I pulled the new assembly apart and there the same torque specs as the ones used to mount the complete assembly.

I was just thinking this could be my issue, I replaced the oil cooler but as I understand this sits on top of the heat exchanger and the oil flows though this to the Oil cooler. So a gasket leak from the EGR cooler may be the issue.

SO I will move on this. Thanks for sharing.