Jump to content

litp.jpg

Lotus in the Peak
28th - 30th June 2024

Nlc - Lister Bell Stratos Build Thread


Dr H

Recommended Posts

  • Replies 668
  • Created
  • Last Reply

The pitting, and the casting lines, could well be the cause of the leaks. From what you've said previously it's not something mechanical (clips, etc.) that is at fault.

Silicone hose is very smooth, so may not be conforming into the pitted surface.

I would avoid using any type of filler in case it flakes away into the system. As I posted earlier, run a bead of sealant around the fitting, just behind the flare. Then fit the hose and clamp up, but not fully. Leave the sealant to cure, then clamp up a final 1/2 turn.

How was the housing cleaned (I'm assuming it's not new by the look of it...)?

I have seen aluminium become porous after chemical cleaning. A few years ago we had some components from a piece of laboratory kit cleaned & re-anodised; even though they looked fine visually, they were full of minute fissures that leaked. We only discovered this when the instrument was rebuilt and we put gas pressure on it. Went through every seal, o-ring, etc. on it before concluding the metal itself was at fault. We took the part off, submerged it in water and pressurised it; result was streams of bubbles from everywhere!

The conclusion we came to was that there were corrosion tracks through the metal that had been stripped out by the chemical cleaning, leaving 'tunnels' through an apparently solid aluminium block. Whilst that was gas-porous, it's may be possible there's a similar thing with your part, which is allowing the slow bleed of water through over time.

Link to comment
Share on other sites

Cheers chaps. Timbo, I think your comments on porosity could be valid, it was something I did wonder about.

The housing had to be specially machined  because I had the heads machined by 1mm to raise compression and it brings the 2 water pipes on the heads slightly closer together. So I can't just swap it out for a new one without a hell of a lot of messing about.

Having said that, the top of the housing that has the thermostat in it comes as a cast piece with the stat installed. That's been replaced so the casting in brand new and that seems to weep too!

I guess a bit of epoxy metal to fill in the pitting and then sand back might help. Worth a go I guess.

If it is porous I could also try bonding a thin aluminum pipe on the inside. The silicone hose that comes of this is a reducer anyway so no issue about reducing the diameter a little further back.

 

Link to comment
Share on other sites

Here's a thing......

I decided to test some of the joints that were leaking. Took the hoses and pipes off the car. Plugged the 2 open ends with caps or plugs, one with a schrader valve in it. Pressurised it and got this!


44331551121_5c9d813ae8_c.jpg

29395749637_ed10ff5eae_c.jpg


The hose is somehow compromised and water has seeped into the structure. This was only about 10psi pressure so presume the coolant is seeping out when it's full and under no pressure. Running the car and bedding stuff it would never have got rid of this.

Pressured it to about 30psi and put the joint underwater. Nothing at all from the hose/pipe interface, but loads of bubbles out of the wall of the hose itself.

Who'd have thought!

This would also explain why it will stay dry for days after first filling and then start weeping. It must take a few days for it to leach through the wall of the hose.

The other problem hose seems OK though so must me the seating of the joints on that one. Did the same pressure test to 30psi and not sign of any air leaks at all. So must be something to so with the seal on the thermostat housing in my previous picture.

Link to comment
Share on other sites

Supplied by LB as part of the kit, but they aren't to blame, they could never have known this was a dodgy hose and the other's they have supplied seem OK so far.

It's made by ASH http://www.autosiliconehoses.com/ - I've used there stuff before (on the S2) and it's been absolutely fine!

I've ordered a Samco one as a replacement and it's over twice the price of an ASH one, so maybe that tells me all I need to know!?

Link to comment
Share on other sites

Good work! Really pleased you've got to the cause of the problem. Never seen this before with water, although silicone can be gas permeable.

Apparently silicone hoses for water use should have a liner to prevent this happening; looks like a manufacturer fault?

Link to comment
Share on other sites

24 minutes ago, timbo said:

Good work! Really pleased you've got to the cause of the problem. Never seen this before with water, although silicone can be gas permeable.

Apparently silicone hoses for water use should have a liner to prevent this happening; looks like a manufacturer fault?

Must be a manufacturing fault. I might cut it open and have a look.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.


×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. Terms of Use