Engine coolant hose outlets curroded

[Jug]

Just spent the afternoon removing all the coolant hoses from my 990SD - fun job...

So I now know why it was prone to leaking, the parts where the pipe go on (hose outlets I guess), the metal had corrosion on them which would undermine the seal.

My plan is replace all with silicon hoses and quality screw clips but what to do with these outlets first?

engine pipe.jpg

My thoughts so far are to Scotch-Brite back to clean metal as best I can (it's alloy I think) and then maybe paint to seal the surface.
Is this a good idea?

There are 2 like above and also the 2 on radiator.

As far as I can see this is a result of water tracking in under the hoses over the years.
Would be nice if there was a plumbers product for this job, something that acts as an assembly lube but then as a sealant when set, is there such a thing and if so is it suitable for silicone hoses?

[billinom8s]

Sounds like a question for Kawasakiracer.

I would just clean them up gently with a green sponge to get rid of the corrosion. The new tubing and good clips should do the rest.

PTFE tape?

[MellowYellow]

WHITE vinegar (not fish & chip stuff) with fine wire wool (or Billlis green pads).

Lemon could do as well.

[Robbo87]

Wot he above said. Except for the the PTFE tape cos it's for sealing the thread on (mostly) brass fittings and mightn't be too grippy on nice slippy silicon hoses. It's been called, amongst other names 'Teflon Tape', which is not stictly accurate but is a good indication of what NOT to use it for.

[Jug]

Okay, but what should I seal them with as it's surely just going to happen again?

Also I'm not 100% on silicone hoses as replacements TBH.

I have read that standard rubber hoses seal better.
I have also read some reviews where people say it can take a few rides (and re-tightening sessions) before the clamps seal the silicone hoses properly.
This may seem trivial to most but on a 990 that means 14 places that could leak and most of them are pretty inaccessible for re-tightening, might just get a new set of OEM rubber ones.

[Mervin]

how about fitting them with silicone sealer that should seal the metal

[Ruffian]

Clean with stainless wool. Or a scotch bright.
Brake cleaner or degreaser.
Then just refit with good quality hose clamps.
I prefer mild steel to stainless as higher tensile strength.

Silicone hoses are ok provided they are decent quality.
Samco/sfs hoses.

Seen some properly cheap far eastern alternatives that have refused to fit previously as the "quality" was loose at best.
Would not use any sealer on the joint in my opinion.

[TLS-Moose]

Use rubber where hidden/hard to reach, silicone where visible/accessible?
Clean down surfaces and seal with paint. What coolant do you use? One with a corrosion inhibitor?

[Jug]

I use a G12 VW spec coolant TLS.

The brand is TripleQX (which is Eurocarparts own brand), it's VW spec OAT type coolant, which I also use in my van.
The corrosion on these tubes has come from outside as the inhibitors in the coolant would have stopped it otherwise.

I think I will clean them down and paint a band around the base of them. That way the hose can still make contact with metal but the rear of it (the area before the clamp) has some protection against the water that might get wicked in under the hose.

[royb]

how about fitting them with silicone sealer that should seal the metal

Fully agree Mervin.

Making sure the base metal is clean, dry and rough (not smooth).
Coat the metal with silicone sealant (bathroom, builders sealant is fine).
A thin layer inside the rubber hose,then push on and clamp. Wait 12 hours for it to set.

The silicone stops the water getting to the base metal surface, therefore no erosion.
This has worked for me over many years that silicone sealant has been available.

[Jug]

Right sorted then thanks everyone.

OEM rubber hoses ordered and clear sealant will be put on them when installing.
Hoses on back order with KTM (Fowlers) so I have time to get over this stinker of a cold before continuing this job.

Need to remove and clean the air filter next.... but I've read I've only got about 10 minutes once I lift the fuel tank up before it dis-shapes and refuses to go back on, so I'm doing F1 pit crew training right now.