Oil leak on send or return oil cooler pipes


I have a very slight intermittent oil leak that seems to originate on the rear junction of one of the two pipes that run from the engine bay, to and from the oil cooler, via the drivers side sill box.

It is more of a weep than a leak, if that makes sense.

There is a Lotus fitting crimped on to the pipe end, in the engine bay, where it exits the chassis rail and it is there that the leak seem to happen.

I understand that the crimped piece cannot be repaired, so I will have to replace one or both of the pipes.


  1. How do I get the pipes out, since I think they are tied down somewhere in the middle of the sill box… ???

  2. Should I replace with the standard lotus part, and if so what will it cost ??

  3. Is there a better part, and if so from whom, and how much ??

  4. Assuming yes to better hoses, should I use braided oil hoses, or will they wear their way through the chassis, and make a hell of a lot of noise at the same time ??

If you don’t need the car for a while you could pull out the existing hoses and send them to be copied to one of those guys that make bespoke hoses.
Don’t have details right now, have to check some magazines, will post later.

But you’d have to leave some sort of rope or guide in placeto be able to pull the new ones through.

But yes. don’t bother with the Lotus ones, they’re not so good.
Mine sometimes leak and then they stop.

Will eventually replace them with a water-oil cooler because I’m not a believer of the aerodynamics of the hot air coming out of the oil cooler below the chassis (better seal those holes)

Had my oil leak repaired late last year was at the oil filter housing where those pipes join in and to my horror the Castrol RS had almost reached it’s flash point, so i have a water to oil cooler sitting in the garage for fitment along with cams. Problem is with m/sport splitter the seal is not as good as it could be for the oil cooler box in the front.

If budget allows go for the water to oil as it is safer in the long run, alternatively make sure of guide rope when removing pipes and it should not be a major problem, just a pain. An oil cooler supplier should be able to make the hoses up for you in a couple of hours, and some sort of foam sheath as used on the origonal clutch hose would solve any rattles which could occur.


You can get hoses made up by Pirtek


They can do it while you wait on site …

You have JLS, BMRS, and I seem to recall there are others, but can’t remember who.

Not sure of the geography down there but do you have to route them back through the chassis? If so can’t you get a union made before it enters the chassis - it can’t be leaking from inside can it?


the risk in doing that will be that you’ll have a compression fit joint in your oil-line…

Thanks guys

So down to the practical bit then…

I suppose I’ll have to drain all the oil out, or some of it, else I’ll have a right old mess…

What is the best way to set about it ??

Obviously undertray off, but will I need to put the car on axle stands or something ??

Any step by step guidance would probably save me from drowning in oil !!!

Rox - I can understand why no joint is better than any joint but I am missing the point with regard to a compression seal? providing it is done properly there should not be an issue.

This has to be preferable to trying to the alternative Mike is looking at - doesn’t it?


Back the car onto some ramps (the halfrauds one’s are a pretty cool for this, says they won’t fit the tyre size but do fit fine), with standard ride hight you’ll have clearance at the front.

Then undertray off, find the sump, will be a flat bit of metal on the bottom of the engine, then there’ll be a sump nut… Undo this and have a container ready to catch all the oil that pours out.

If you want to do an oil change while you’re at it (may as well) warm the engine up before you drain so the oil will be thinner and drain better… But also be host so careful

find the sump, will be a flat bit of metal on the bottom of the engine,

Very “Vorsprung Deutsche Teknik”

Would the baffled sump I just had fitted be similar to the sump referred to, or am I misunderstanding!!



Six glasses of pure malt is a hell of a way to start an evening !!!

Would the baffled sump I just had fitted be similar to the sump referred to

Don’t know, cos I’m baffled too

PS 6 glasses


If you are going to go full monty and replace these pipes… (prolly best way imho - even tho it looks like it will be hassle).

  1. Can’t Bernard give you top advice ?
  2. If not then i’d say…
  3. Drain oil as normal (like RL says) then remove the oil pipes at both ends (ie engine end around the oil filter 1st, then at the front of the car from underneath – be ready to catch more oil here )
  4. This next bit i’,m not sure of but looking at Uldis rebuild pics and the partslist drawings… and provided the holes in the chassis siderails are big enough to allow the oil pipe connections to feed thru (which i guess they are otherwise how’d they get them in there in th efirst place?), then you need to tie some nylon cord (or something that won’t snap ) to the pipes at the front of the car such that the cord won’t pull off… make sure its long enough eh…
  5. then gently pull the pipes thru from the rear of the car - i wouldn’t pull them thru from the front because then it looks like you’d have to negotiate a rise within the chassisrail - whereas if you pull from rear of car when the hoses dissapear into the hole they will drop down to the bottom of the chassisrail and then it looks to be a straight pull to the back of the car .
  6. when running your new oillines in, i’d go front to back again for the same reason. Just make sure you feed them into the hole the right way round (its the sort of thing i’d do wrong and after spending hours of frustration i’d have to do it all again.

Don’t take any of the above as gospel 'cause i’ve never seen it done and i’ve never had to do it myself.

I also conveniently ignored the access problems you will have to the points where the oil-lines dissapear into the chassisrail at front and back… maybe you can do this thru removal of wheel arch liners but i fear it might be a clam off job ?? need to wait on Uldis or someone who will have a better idea to come along.

Wouldn’t need to be a clam off job.
Front and rear right wheels liners off and you could do it.

As Rox says, there is not much for a recipy here, just common sense.
-You need to free both ends, right.
-To do that you’d have to drain as much oil as possible, maybe put some air under (low) pressure on one pipe to get the rest out.
-if I was you I would plug the ends with some sort of threaded plug so nothing came out inside the sills.
-one side of the plug should end dragging some sort of smooth plastic hose just as a future guide.
-with the hoses out you can copy them well (thread type and hose length). Just send them away to be copied. Simon Erland gave me once the phone of the guy that made the hoses for the MS series but I can’t find it now. Call him.
-one you have them, you pull the new ones in with the hose that you left in place.
-and connect.

But, if I was you, I would get Bernard to do it.
After all, there might be some changes that you don’t know about, and I would expect him to be eager to give you some customer support.
Heck, I would expect him to help with the repair for free, since the conversion is practically new (or, you just buy the hoses)

But the fact that you’re asking means to me that you’re not confident on doing it. Better let somebody else do it.

Bernard is the man.

I’d be happy to help and obviously I am more than happy to foot the bills anyway…

Only problem I have is that I have just taken on a second job, and extended my hours on the original job, so I will be working 56 hours a week on the first job, and all other daylight hours on the second job, maybe another 40…

So when the ‘pucklechurch’ can I get the car repaired ??

Maybe my ever loving son and (potential) heir, who has much more mechano skill than me will step into the gap (or move out of the house - hee hee !!)

PS Pucklechurch is a little village close by, which conveniently doubles as a clean expletive!!!

Sodbury’s an alternative Mike.


ps. Use to live in Kingswood

Sodbury’s an alternative Mike.

Or this one in Orkney:


Would you want to take the coin holder off as well? With little monkey hands you can reach into the sill to help move stuff about, it really helped when replacing my clutch hose!

Oh and the baffled part of the sump will be inside the same sump you already have

Thanks Mark - good tip…

The sump I already have is on the floor of my garage, and the new baffled sump isn’t - if you see what I mean !!!