2006 Exige S

General Owners Cars
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My thoughts exactly :mrgreen: However, let’s not give Lotus too much credit… they’ve made some howlers in the past.

Yes likewise, Lotus parts diagrams say it’s thermostatically controlled however I think the counter argument to that is that the thermostat isn’t an “open or shut” case so to speak. It always allows a little bit to circulate to prevent any big spikes/drops in temp… which I guess makes sense.

When it all comes down to it though, i’ve monitored oil temp across two cars now - one my air/oil Exige with twin coolers and my other was my Elise which just had the factory air/water circuit and both show similar warm up times. So I remain unconvinced.

The several meters of hosing an extra oil are hard to argue with, I can certainly see benefit in going rear mounted (whether oil/air or oil/water) providing enough airflow can be had. I think if I was to go Laminova, I wouldn’t be too hasty in ripping out my old plumbing just in case I’m underwhelmed with the efficiency of the new setup.

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What fantastic account of your Exige ownership experience… :thumbup:

Lovely Exige too - Laser Blue has quite a nice hue, especially under artificial light.

I will take some time to go through it all, but I will, which as a Lotus newbie will no doubt be hugely educational.

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Cheers Lankan, hope you enjoy it - I went down the suspension refurb route on my previous car (Elise 111R) so if you’re interested in that, there’s a thread lurking around on Pistonheads somewhere I can dig out for you when you’re finished here!

Back to my oil cooler situation, I doused the front side of them and lower union in brake cleaner and gave them a good hose down last night, unfortunately I can’t get access to wipe it all down properly with a rag so they’re not totally clean… but clean enough. I fired the car up in the garage and let it come up to temperature (note for future, my pizza oven comes up to temp much quicker than the car does) and once the oil cooler circuit was live I gave the car some beans to build up some oil pressure. I couldn’t see any sign of leakage, car was running for a good 25 mins with no real evidence.

This morning the baby decided to grow a tooth at 3am so once we got her back down, I was wide awake so decided to get out and do some miles. With much attention paid to the oil pressure gauge I did a good mix of cruising, ‘pulls’ on second cam and tried to keep the oil pressure up as much as possible. About half way round I stuck a torch into the front mesh and thought I could see some new oil, but the light made it very difficult to see past the mesh and I may have been seeing things. I got back home for a proper look in the garage and sure enough I couldn’t see a spec of fresh oil, just a bit of old staining from the old lot.

On the ride home I was processing my options, in many ways I really wish that I found a real obvious leak today because at least then I could plough on with some conviction.

I still really like the idea of going laminova, mainly to liberate the car of so much plumbing - even if the oil temp concerns in the US are unfounded, it’s still a lot of weight and puts the coolers in a fairly vulnerable place judging by the catalogue of stonechips I have in the immediate surrounding area!

However to counter that, it’s going to add load onto the water cooling circuit - and in theory my car is pretty much already well loaded up thanks to the AC condenser and charge cooler pre-rad. I will say though that switching to top mounted fans seems to have had a really big impact on my engine coolant temps, I struggle to get above 82/83 degrees on the road whereas pre-charge cooler it was high 80s and low 90s on track, so maybe I’ve gained some capacity for a laminova?!

With all that in mind, I’d pretty much decided to just take the clam off this weekend and see what was going on. Either the link pipe between the two coolers is not sealing on both coolers, or both coolers have been damaged - potentially with a hairline crack somewhere from the force of undoing/redoing the link pipe over Winter. I could attempt to resolve the sealing issue by refitting the pipe with some loctite RTV or something, and if the coolers showed obvious damage I could whip out the spares (though they look pretty tired tbh, not sure how much confidence I have in those!) so ultimately I could ‘fix’ whatever the problem is for effectively zero cost, just a few hours of clam removal/refitting.

However, now that I’m home and I can’t see any leak evidence - I’m now back to not knowing wtf to do. I don’t consider clam removal particularly hard, but it’s not fun either. :crazy:

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I had a laminova on my old S2 Elige… Circa 300 bhp with a sequential. Pro-alloy triple pass rad, no A/C but with charge cooler rad. The system couldn’t cope, so i added a small radiator into the heater circuit using a rad in the nose where the LH oil cooler was. That fixed it
Being honest i think you will find your car is OK as is, but with a laminova you will find its capacity limit…
Now for a shameless plug
I have new original spec oil cooler rads on the shelf

Happy to ‘look’ at the prices if buying both LH and RH at the same time

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Cheers Dave, it’s good to get first hand knowledge of the laminova setup and I appreciate the offer to do a deal on some coolers… read on.

I took a picture this morning btw, already feels like days ago but it was only 5 hours…

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After making my post this morning, I knocked up a greasy breakfast and discussed my options with the missus on a sunny patio. Not really knowing or caring she just told me to take the clam off (what’s a clam?) as it’ll keep niggling me otherwise.

65mins later…

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:laughing:

I can now have a proper look at the issue, and it was definitely worth removing the clam even though I’m still not quite sure what the full extent of the problem is.

First off, the OS cooler seems the ‘least leaky’ as the only evidence I can see is an oily damp patch in the fins itself - it doesn’t photograph well but you can just about make out a darker/blacker patch above the union.

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So either:
a) The union has been weeping and airflow has flicked it up into the fins
b) There’s damage to the core (unlikely as fins are unmarked in that area) and its dripping down towards the union
c) It’s the union leaking on the other side and it’s dripping through (unlikely as it seemed dry on the ‘wheel side’ of the cooler)

If I was desperate to save money, I’d gamble on keeping the OS cooler and just refitting the hoses maybe with a bit of RTV on the threads. I’m not sure I’m that desperate though, so may just swap it.

Onto the NS cooler and we have a bit more to look at. This has got evidence of a stone strike going into the bottom right corner, much more dampness in the core and there were fresh looking (golden coloured) drips on the under side of it. Amazingly no evidence of oil anywhere else, not in the clam, undertray, wheel arch liners, nowhere - so it’s either very, very recent or it’s dripping so slowly that it’s barely noticeable and surface tension is keeping it all in check. Either way, not good.

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Other observations are that the rubber o’ring in one of the barbed fittings (the new fittings that Lotus do as a recall) seems a little pinched - does anybody know what size these are to be replaced?

I appreciate the thoughts of the people, I’ve got a trackday in 6 days time so I need an option that’s quick - we’re lucky to have access to [mention]seriouslylotus[/mention] in that instance :wink:

Dave - talk to me. :thumbup:

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Echo Dave’s comments on the Laminova. I had an almost identical setup and it couldn’t cope with sustained track use. My solution was to add an additional air to oil cooler in the drivers side sidepod.

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Oil’s always a pain as even the slightest drop spreads massively (anyone who did the ‘oil drop’ test in physics can confirm!) and when it’s warm on a metal surface it will spread quickly…so there’s only the tiniest weep. A few thoughts, then conclusion:

  1. From what I can see you have steel unions on the link pipe going onto aluminium threads on the coolers. Quite a heavy chunk of (harder) metal onto something quite soft by comparison.

  2. There’s a length of the link pipe that’s unsupported going to the coolers.

  3. The difference in thermal expansion for aluminium and steel means the union shouldn’t slacken when it’s hot (aluminium expands more than steel). This also means the aluminium will contract further once it cools down.

  4. There looks to be a some evidence of surface corrosion on at least one of the steel fittings (OS cooler).

  5. The ‘focus’ of the spread pattern is the unions on both sides.

I’m not sure point 4 is particularly relevant, but I suspect the link pipe may be vibrating (possibly the unsupported lengths hitting a harmonic - difficult to check, admittedly, unless you can have someone watch them whilst you increase/decrease revs stationary with the clam off).

Combined with the strength/weight of the steel fittings compared to the aluminium, this is allowing a tiny bit of oil to escape through the threads. Once out, the hot oil is spreading out to give what you see now.

This would be consistent with seeing similar issues on both sides. It would be less likely to be that similar if the cause were to be cooler damage, eg. stone hit.

Any solution is going to mean draining down, so:

a) Drain the oil, remove the link pipe and check the state of the threads on the coolers in case of any obvious scratches, burrs, etc. that could be causing the weep. Clean up anything that you find.

b) The coolers can be checked for leaks by pressure testing. This would involve removing them but if you’re concerned it would identify quickly any problems , since it’s done with gas, which will escape through a much smaller gap than oil. Testing might be possible without removing the coolers or link pipe - take off the top fittings on both coolers and block off one, Put some pressure on the other and give the whole thing a spray with soapy water. Check for bubbles.

c) If the coolers are both good, have a replacement link pipe made up but with aluminium fittings rather than steel to reduce the load on the connections. Make sure everything is scrupulously clean before fitting and tightening.

On the subject of o-rings, in general it’s not unusual for this type of seal to deform under load/heat/time. Always worth replacing whenever a connection is opened up. Sorry I can’t help on the specific size but someone on here will know! O-rings are so cheap (try a supplier like Simply Bearings) that it’s false economy not to replace them.

Hope that helps!

Cheers,
Tim

328

Great info, thanks for all that Tim.

The link pipe is supported a little better than my original pics suggest, as per the Lotus TSB for the oil line recall it’s cabletied (via 3m pads) into place on the underside of the crash structure in this sort of W shape.

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It doesn’t take a huge stretch of imagination to see those 3M pads giving in at some point, and when I first took off my front clam they were all dried up and failed with the pipe sitting on the undertray itself - which luckily isn’t far to fall.

I’ve given this a lot of thought and I think it’s highly likely to be an issue with the threads and/or o-rings rather than being damage to one or both of the cores. If the cores were damaged surely there would be high pressure jets of oil spraying everywhere at 5bar :laughing:

That said, if the threads are knackered and not allowing a proper o-ring seal, then that still leaves me needing new coolers even if the cores are sound.

I removed/refitted these oil coolers over winter so bad workmanship on my side is a very real possibility, but considering the screw fits were all properly tight with no obvious cross threading etc, I struggle to figure out what else could be cocked up - which just leaves o-rings. I did swap them last time round, but I just eyeball matched up the sizes from a variety box of hundreds that I’ve got lying around. I could have got the wrong thickness, or maybe they’re not up to the same spec as the originals - who knows.

I can’t seem to find the spec for the original o-rings, a sledge hammer approach could be to order totally new fittings from Lotus which I imagine/hope include o-rings but timing isn’t on my side for that.

I’d love to get the cores pressure tested but no idea if I can get that done quick enough (trackday next Saturday). I do have a spare set of coolers from an older and higher mileage 111R but they’re completely unknown and have probably been mistreated over they years from being lobbed from storage box to storage box - not sure what I feel about bolting those on.

I’ve already given all of the pipe fittings a good clean out with a pick and some brake cleaner so they’re all ready to go. I’ll spend the rest of today trying to gauge what I think about the health of the cooler cores and then I may bolt everything back up again tonight perhaps using some RTV on the threads. Though I know the threads should not be sealing anything, this will give some piece of mind that:

a) They’re not going to shake loose
b) Protection against corrosion between the threads (the link pipe on my spare coolers is practically welded on due to the galvanic corrosion)
c) Might cushion vibration/movement a bit on the o-ring sealing face if the threads are chemically locked together
d) It’s just piece of mind, if an o-ring fails it’s a bit of a last line of defense.

I can then let the car run for a good chunk of time tomorrow on axle stands and pick out any weeping at all. If there are any doubts, I’ve still got time to buy new coolers from Seriously Dave and even look at getting all of the fittings replaced before the weekend. Time is my enemy here really, I’ve got no intention of cheaping out on a solution, but I just need something in and robust by the end of next week!

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Couple of quick points/ideas:

  1. Rather than threadlock, give the threads a couple of turns of ptfe tape. Normally I’d never suggest that but it might help as a temporary job, if only to see if the weep stops.
  2. Definitely replace the o rings,.
  3. If it turns out the coolers themselves are OK but the connections aren’t, a decent fabricator should be able to replace just those.
  4. Link hose does look really prone to waggling about.
  5. Consider new hose with aluminium AN10 fittings, and having matching stubs on coolers.
330

What are the o rings you refer too???

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Inside the screw fittings on the oil lines. Will grab a pic when I’m home.

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That will be your issue. They don’t have an ‘o’ ring to seal them.
They use a mechanical seat that is a seal. Using ‘o’ rings or PTFE (Plastic tape for everything) is introducing foreign bodies that will stop the mechanical seat from sealing. You could put the worlds supply of PTFE on the threads and it will not seal either.
Make sure the seats on the cooler and hose fittings are clean and free from foreign objects. Pretty sure it will then seal nicely

333

Funnily enough, I was sent a photograph of #138 yesterday with its front clam off, and it shows that all 3 sticky pads had come off!

Couldn’t you anchor the pipe to the holes at the bottom of the crash structure using tie wraps - at least to the first two holes? Also, in mine, the union joints have a 90-degree bend, as described below, which is an excerpt from DeRouere:

Part Number: A120K0082S
Description: Hose, Transfer, oil cooler RH to oil cooler LH
Notes: 90 degree connector. For '11MY on cars (secured with items 29 & 30) or pre '11MY where previously fitted in conjuction with item 22a as per Service Bulletin

Items 29 & 30 are the aforementioned (3M) sticky pads - cannot imagine why Lotus thought that this was sufficient to keep the link pipe in place! :wink:

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Indeed so. As I am not familiar with these, I assumed the o-ring was intended to be there. Presumably, then, it is already an AN fitting?

Equally, as posted, I would normally not advise ptfe on connections where it is not appropriate; however it would have given some indication of whether poor threads were the site of the apparent leak (at work we use a lot of conical seat ferrules on gas analysers. Similarly these need no additional seal).

I still suspect the materials choice on the connections isn’t the best and the link hose simply looks designed to cause issues.

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Thanks again guys, the o-ring thing is definitely a mystery. My coolers 101% had o-rings when I first dismantled them, I didn’t just add them for the hell of it(!) so who knows why they’re in there.

Couple of photos:

This is how it looked when I took it off:

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And if I pop the o’ring off, you can see there’s a machined groove in it which looks like it’s supposed to accept an o-ring:

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So my next question is, does it look like the Lotus dealership that did my cooler line recall used a non-standard fitting for it - or do all of the fittings have that groove machined into them but with no o-ring installed?

For what it’s worth, I popped an o-ring out of the cross-over pipe and it cracked immediately - so looks like whatever I used is not oil rated or something, it’s just a brittle worm now - so that could be the cause of at least one leak!

Really struggling for ideas now, I don’t think I’m going to feel particularly confident putting this back together until I can solve the o-ring mystery.

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My crash structure doesn’t have any holes in it, if it did I would absolutely lob some cable ties through! I don’t want to be drilling new ones into such a critical aero device :laughing:

Something certainly changed though on later S2s - as you note they switched to 90deg elbows rather than the 45deg ones on mine, and apparently put holes in your crash structure. :mrgreen:

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I found a copy of the recall/TSB document from Lotus and it seems to suggest that oil seals (I assume these are the o’rings?) are required:

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Well that is certainly an o-ring, in a groove, that looks for all the world as if it is intended to be there!

Seems to be DIN3865, 24-degree cone with o-ring? Although the cone on yours looks wider…

What was the reason for the recall, originally?

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As far as I’m aware the barbed side of the fitting was not fit for purpose and teamed up with a crimp/clamp that was also naff - hoses were just popping off the ends :astonished: The recall simply chopped the ends off, put new ones in with much longer/deeper barbed sections and better clamps. The coolers themselves never changed as far as I know.

I’m going through my vast collection of o-ring variety packs, I’ve found what I believe to be an exact match but it’s green (from an aircon servicing kit). I’m trying to get some info on whether or not that would be suitable for this application, AC systems are uber high pressure and subject to big temperature swings, so providing the oil doesn’t actively disintegrate the material I imagine they’re better than a boggo black one?!