A film of oil is collecting around the bottom drivers side corner of the radiator and over the connecting pipe from the thermostat. With the grill off it can be seen extending up the sheet metal side cover for the radiators assembly to around half way up the fans.

I reckon the most likely source is the transmission oil cooler.

Whats the best way to get at things so I can see if the leak is on the radiator itself, connection or pipe. RAVE implies that you can see straight in once the grill is off but I'm blowed if I can see the source. Be nice if it were just the O ring seal but that is probably way too optimistic. If I do have to change the cooler is it a drain the transmission job or can it be done with minimal oil loss by setting the car nose up so only the cooler contents escape and topping up the transmission afterwards?

If it is the cooler which brand to choose? LR Direct have Britpart £100, Allmakes £150, Land Rover £250 approximately.

On a related note does anyone have a feel for how many of those nylon nut thingies that take the grill fixing screws are used on the P38. Part CZK3264L. I need new ones for the grill but, at 20p each, its awfully tempting to get a decent bunch for stock. All the suppliers say used in various places but give no idea how many or how various. Got a thing about not reusing over age plastic stuff if at all possible. £10 or £20 worth on top of my next parts order is hardly going to break the bank but no point in getting 3 cars worth!

Clive

Hi Clive.
I had this issue when I got mine a couple of years back.

Mine had been leaking a while, and so you get oil and dust caked on to the fins of everything, and it is very hard to spot the leak. You will have to remove the grille, and then i think you should be able to move the coolers a little to inspect between them - but it will probably be inconclusive. If you have red in the ABS tray under the rad then I guess you have your answer

I see no reason why you can't remove the gear oil cooler without draining the system - up to you when you want to service the box. But, it may get messy - high probability the input hose (the hot one) is "welded" to the aluminium thread on the gear cooler. Even if it does come off - do not be fooled - there will be ali stuck in the threads - cd be best to order a hose in case. But if you have to change the hose then the other end is on the transmission housing - prepare to get ATF down your arm...

I used LRdirect and got a genuine LR cooler - not something I do normally, but if IIRC there is a special mounting on it and i had read some reports that some of the aftermarket ones didn't get it right - and I just wanted an easy life/ straight fit.

According to LR cat the nylon retainers are used i. on the grille and ii. below the windscreen for the plenum etc - so 10-15 shd work

Hi Rob

Thanks for that. Your count on those nylon retainers is about the same as mine so 20 on my next order. 20 years is a good life. The frustration factor when one gives up is about a million times greater than the cost. Annoying that the ones I rescued from my Lancia Beta HPE are bigger, I guess 35 years isn't long enough to marinate into something useful! As its only one right now I can always make another if I absolutely have to. Bitchy job. Hate machining nylon.

Colour looks as if it might actually be more black engine oil than transmission red but not really enough to be sure of the origin. Yet! Mostly its just dirty. At least if it is the engine one I only have to take out one reducing the risk of lunching the threads on the alloy radiator stubs. Absolutely not among my favourite playtime toys. But if it is engine I'd have expected the evidence to start higher up. Shoulda taken pictures when I had the aircon condenser out so I'd know what I'm looking for.

Clive

Clive re oil... what car do you have? A v8, or diesel? a V8 shdnt have engine oil in that area... if the leak's been there a while then ATF does look v black - it took me ages to clean out all the muck. the dust and oil will have completely blocked the fin structure on the coolers (self-sealing rad lol), and the ram air will have dragged ATF back into the radiator too.

Rob

My car is a V8 4.0 HSE model year 2000.

Went out for another look as its not so bright outside today which makes it a lot easier for me to see things from underneath. I can now confirm that all the unions on both engine and transmission oil coolers have no leaks. Nothing from the ends of the coolers either. All I can see without pulling everything off is a very light dusting of dark oil on the just visible recess at top driver side of the transmission radiator. Clearly now't to do with the oil I'm seeing.

That is collecting all over the inside of the metal panel on the drivers side outboard of the radiators et al and running down to make the bottom of the radiator wet in that corner. The actual oil wetted area on the metal panel starts about level with the fan spindles which I feel to be consistent with spray from a leak at the bottom of the transmission cooler at the end plate joint or close to it. But I can't see any oil evidence elsewhere. Generally its all remarkably clean under the front of the car. not perfect, there is a touch of oil around, but weeps / oil dampness not leaks.

Clive

There is also an Engine Oil cooler, any dampness around there?

Rave shows the top cooler to be for the engine oil, and the lower one to be for the gearbox for post 99 v8 models. Not sure on the p38 but on the Disco 2 there are power steering pipes somewhere around that area, as the previous owner of mine had to replace one of those after it split, That to me would be more likely to produce black oil marks than anything else on a petrol. Also not a lot of ps fluid is needed to make a real mess around the engine bay area as it doesn't seem to disperse particually well.

Thanks for the help folks.

The fundamental problem is that all the bits and joints I can see on both oil coolers are clean and oil free save for the very small misting deposit on the top drivers side of the transmission cooler. I really need to get better visibility of things around the coolers so I've got a decent chance of figuring out where the leak is coming from. Stripping out the air conditioning condenser will give me all the visibility I need but de-gassing and re-gassing is a problem right now as my usual mobile air con service gal is obviously not working at the moment.

The radiator/cooler/condenser pack side of the drivers side metal panel is sufficiently oil wetted for it to run down and collect on the radiator bottom corner. The start of the wetted area looks reasonably consistent with a pinhole leak on the transmission oil cooler possibly just at the joint of the core and end cover or, more likely, an inch or two from the end towards the middle of the cooler. Just far enough in not to be visible. If it were at the end cover I'd expect a bit of "up-spray" to be visible.

Can't seem to get a decent run in with my fibre optic "borescope" camera either. But, to be honest, I'm pretty much pants at driving and interpreting the image from that thing. Despite being cheapy LiDL it works well. But most of the time I just wish I could figure out what its seeing.

Clive

Spray it all with brake cleaner which will clean it all off and evaporate very quickly leaving everything clean and dry. Then run it to see if you can see the origin.

Thanks. Brake cleaner sounds a good idea but is it paint safe? Back in the day we used to use cheap cellulose thinners!

Naturally I haven't got any in stock. Guess I'll wait for another super warm day, gunk'n water it down then tape a bit of cardboard, white painted hardboard or whatever onto the panel to collect the spray.

I guess its just me but I never seem to think in terms of looking for leaks, sprays et al real time with things running. Always want to try and trace the path afterwards with everything stopped and cooled down.

Clive

I was looking for the source of a power steering leak on my old Maserati last week. Everything was covered in fluid with drips off all low lying parts. Sprayed it with brake cleaner (which appears to be paint friendly as it evaporates so quickly it doesn't get chance to soften the paintwork) so everything was clean and dry. Started the engine and could immediately see that it wasn't leaking from a hose or banjo joint as I'd hoped but I've got to take the rack off and source some suitable seals.....

Gearbox coolers seem to leak as one of the P38 rites of passage. They usually leak on either of the end tanks - and I doubt there is much hope in repairing.

You should probably buy both lines too while you're at it, as the steel vs alu corrosion results in either the connections snapping off or stripping the threads on removal.

Guess what I found on mine while having it in bits for the engine work? Gearbox cooler leaking :) So that will be the third one this P38 sees when I get around to replacing it... to be fair the one it has now was a used one that happened to comply and come off my old P38 without too much fuss.

The one on our red P38 did not come off without a fight however.

Last thing - the britpart (and maybe others, I don't know) replacements don't have the screw hole for the overheat switch on the end tank. I think I stuck it on with JB weld rather than risk drilling/tapping a £100 heat exchanger.

For what is worth, is much easier to remove the engine coolant rad than the A/C one (piping might be very well "welded" on the threads of it, so better not touch it unless very necessary).
If you just remove the pipes cowl and fan, with minimal loss of coolant you have full access to the oil and g-b coolers, and you can assess the situation.
These two coolers "loosing fuld" cost me an engine radiator and almost the entire engine itself ... don't let it go on for too long.

Great. Going in via the engine radiator side sounds like the best plan it I do confirm that its an oil cooler leak and not something totally outlandish.

Need to change the top hose assembly anyway as my stubborn cool down water leak eventually turned out to be from the top T piece connection. Got the short trip timing just right about 3 weeks back and it was lots more enthusiastic than usual with visible leakage from the smallest pipe at the T. Screwdriver tight on the jubilee clips obviously wasn't enough so they got a socket spanner heave. Which I seriously didn't like on plastic. But leak is now back to a couple of itty bitty drips at worst. Always felt that that new hose set was touch slack on the pipes.

Clive

The T pieces are pretty sturdy - the wall is 5-6mm thick, PA66 GF30... I know you are a man who appreciates detail

I don't like plastic Tees or joiners, they will always leak after a while. I'd be included to swap it for something like this https://www.merlinmotorsport.co.uk/p/32mm-aluminium-t-piece-with-16mm-spout-mhj-t32-16 or if you can't find one of the correct size, one of these https://www.merlinmotorsport.co.uk/s/cooling/aluminium-hose-adaptor with the correct size stub https://www.merlinmotorsport.co.uk/s/cooling/hose-adaptor-take-offs. Although with your fabricating skills Clive, I'd expect you to make something.

Good idea on the metal Tee pieces. Something to look into when I've got the hoses off.

Don't remember my plastic Tee as being that thick on the sidewalls but it was about a decade ago that I fitted the hoses so they are probably due for a change anyway. Got a nasty feeling that the "whole engine" hose set I bought shortly after purchasing the car might have been Britpart in a plain bag. Have since been told that the spring clip types are better on plastic as they, supposedly, have effectively constant clamp pressure despite any thermal shifts of the plastic.

That Tee isn't something I'd fabricate. More trouble than its worth to do it right unless totally unobtanium. Its taken a few years but I'm finally learning that just because you could doesn't mean you should.

Clive

I've taken plastic Tees off that have been used on LPG installs and every one has distorted so is no longer round. Maybe because they've had Jubilee clips on them, but it doesn't instil confidence when I've pulled on one hose and the Tee has cracked. I make them up using 22 and 15mm copper and Yorkshire fittings.