What's the going way to seal a sump on a na engine. Mine keeps leaking and I've done it 3 times now. 1st time just gasket, 2nd was gasket + hylomar blue, 3rd was rtv sealant. I'm thinking of buying some of the sealant used for 300tdi sumps next...

It doesn't **** out, just drips all round.

I use a gasket and three bond semi setting stuff.
Even using hylomar, it should seal if the surface is clean. Has it been over tightened and distorted round the holes at some point? Is it definitely the sump and not where it meets the timing chest or rear bearing?

gasket and hylomar is best but apply some silicone across the joins at rear main cap and timing cover to block

Cheers guys, my next oil change is due shortly so I will get it then. I'm pretty sure its the sump because I rebuilt the engine 2-3 years ago and the last few times cured it in the short term. Also it seems to be leaking all round high up and from what I can see the drain holes and anything above the sump is clean. I think I also need to be more careful and patient cleaning the mating surfaces and manoeuvering the sump into position without knocking the gasket/silicone.

I've been deeply into this problem myself, and have I think all of the solutions..

After a lift and replace of the same engine, I started getting bad oil leaks at the rear of the pan.
With a dry rag in the hole for the wading plug at flywheel housing bottom, it would stay dry after running, and collect no oil; hence, not a leaking rear seal.

I had the pan on and off enough times with different gaskets, and then assumed it was the leaking t-seals, which had just been done. The engine later failed on me, as the bores were badly worn.

Upon disassembly, it was noted that some of the composite washers that hold larger banjo bolts on the small oil pipe at the rear of the block between block and head were cracked, and since replaced with Genuine LR.

That pipe might be impossible to get to with engine in, particularly if lifting brackets are in place.

I hope I saved your garage floor here.

I've had the same issue with my transfer box pto cover which I did with the same stuff as the oil pan. I think I've just used a cheap rtv sealant as I've now bought the stuff Ashcroft use and it's much thicker and sets firmer. Just done the pto cover, sump I'll do soon.

I did have a leak from that pipe which I cured a while ago, mine is definitely leaking from the sump/block joint.

A favourite leaking place is around the rocker cover, which you don't find until it drips off either the sump or gearbox

They do that by design to stop engine block and components going rusty

First, let me say there's an excellent video on diagnosing Land Rover engine oil leaks on the Internet. They show an expert mechanic telling a young woman 4x4 driver what to look for and giving step-by-step instructions and diagnostics. See my further post, after Huddy84's reply.

Ok, a bit of history: At the time Land Rover built the 2.5 N/A engine, a silicone sealing compound was used (not a gasket) but, ironically, in those days, the available sealing compounds were not totally resistant to oil. As a result, over time, oil leaks from the sump pan are inevitable. I guess this is why it's said that all Land Rovers leak oil. But they don't have to. They can be made totally leak free.

Fortunately, in 2017, you can buy sealing compounds that are resistant to oil. WURTH RTV Silicone Sealant is recommended by the prestige Land Rover restorers.

As others have stated, what looks like an oil leak from the sump pan may actually be oil running down from a leak higher up in the engine. In my case, I had a leak from the rocker cover as well as the original sealant on the sump pan having been degraded by 20 years of oil contact on material that wasn't totally resistant to oil.

Looking to choices between fitting a gasket or a 2017 specification sealant, I chose to use flexible RTV sump sealant over an aftermarket gasket. My rationale was that although the gasket would be easier to fit, the sump pan is somewhat exposed to striking rocks or ground when driving off road, and I wanted a seal that would have some flex to enable it to remain sealed if the sump pan got bashed. Gaskets are relatively thin material, so require everything to be nipped up nice and tight; a couple of bolt heads sheared on a rock would jeopardize a gasket's oil integrity, while a flexible material bonded to both sump pan and bottom end would likely retain its integrity well enough to get me home. The army still use sump sealant and my 1987 Ex-Military Ninety has survived 20 years' "active service" in extreme off road conditions -- including operations in the 1st Gulf War -- with its original sealant only weaping, so sealant it was.

I chose what is said to be the best quality brand for this critical repair: WURTH flexible black RTV Silicone Sealant, which comes in an aerosol-powered can, and (being aerosol) is extremely easy to apply without any special tools.

Procedure: drain all engine oil. Remove sump pan. Scrape old sealant from sump pan and bottom of engine with Stanley knife blades. Clean ALL oil off and around contact surfaces (else silicone won't stick!). Apply 8mm bead of sealant to channel around edges sump pan, GOING AROUND OUTSIDES OF BOLT HOLES; as is obvious when you think about it. Offer up sump pan to engine and hold, lightly, in place with 4 bolts. Gently screw in those 4 bolts until the sealant just contacts the bottom of the engine. Loosely insert the other bolts. Using a similar procedure to tightening down a cylinder head, gently nip up opposite pairs of bolts going around the sump pan, but Do NOT fully tighten. You want it to be tight, but NOT fully tight. LEAVE FOR AT LEAST 24 HOURS. Let me say that again: LEAVE FOR 24 HOURS! This allows the silicone sealant to air cure. Then you can fully torque up those sump bolts (only around 6 ft/lbs if memory serves me). Ideally, leave things for 48 hours, before refitting the engine oil, but 24 hours is the recommended absolute minimum curing time.

Job done. I've not had any oil loss from my 1987 B19 N/A sump since doing this job.

It's an easy (if oily) job. Try to find that video, and don't forget your Landy will be unavailable for 24-48 hours while the sealant fully cures,
Rick

In the end I used a decent sealant, same stuff Ashcroft use to seal their transfer boxes. Roughly followed procedure as above, I put sealant both sides of the bolt holes just to be sure. Nipped bolts up then next morning tightened them up.

Same stuff also finally cured the leak from my pto cover plate also

Forgot to mention, the bolts holding my sump pan to the engine were not all the same size -- I thought they would be -- so make a note of which size bolts fit where!

Anyhow, here are the two excellent videos I mentioned, in my post, above:

WARNING - they show use of aerosol Brake Cleaner to remove leaked oil -- so you can see where the oil is coming out -- DON'T do what I did, and stay too long under the vehicle (especially if working on your driveway) -- as you shouldn't be inhaling this stuff! Probably best to spray onto a cloth, when you're outside the vehicle where the wind will blow the fumes away, then only stay under the Landy for lots of short spells. I inhaled some of the stuff (read warning label) and was rather unwell for a few hours. Stupid!

Video 1) is about diagnosing fluid leaks:

Video 2) is specifically about re-sealing a leaking sump pan:

WÜRTH - "SUPER RTV - SILICONE Black" product code = 0893 321 10 and (in smaller print) 072. Bar code is 4 053479 652276.

These videos are part of a whole series of videos that I've found from the same people. They're all really excellent, because everything is really well explained.

Rick