98 V70 need ideas - corroded metal nipple - coolant

[98v70dad]

I am doing a timing belt and water pump replacement this weekend and will have to drain the coolant.

The connection between the rubber hose that comes off the bottom of the overflow tank and the steel line on the aft side of the engine block has been badly corroded since I bought the car a few years ago. The "nipple" end of the pipe is corroded to the point that its bumpy and slightly pitted. Last time I did a coolant change I cleaned up the corrosion as much as I could and made sure to thoroughly clamp the hose on. However, I'm pretty sure it still seeps a bit since it always looks just a little damp. So, I'd like to do something to mitigate the problem while the coolant is drained.

The only idea I can come up (other than letting it seep) with is to wrap the corroded area with a few wraps of self fusing silicon tape to help fill in the voids . They sell this stuff in the plumbing aisle to wrap the outside of low pressure pipes to fix small leaks. Its actually no good in that application but I think it might work for my problem. If you haven't seen it, it's tape about the size of teflon plumbing tape but made out of "almost cured" silicon and it fuses to itself and won't come apart when wrapped. Its great for wrapping wires. Anyhow, I'm a little hesitant to do this repair idea because I don't know if it will stand up to temperature and the chemical properties of the coolant. That said, the spot is easy to watch and easy to get to if it doesn't work out.

Cutting the corroded length off probably wont work because what remains is too short and too close to a bend. A new part is several hundred dollars and replacing it is a fairly involved so getting a junk yard part doesn't really appeal to me.

So, I bet all of you are more creative than me...any good shade tree ideas?

[98v70dad]

Wow. Zero for 45. A new record for one of my posts. There's no wrong answer to this question. I'm just looking for ideas. The other idea I came up with was to put some RTV gasket sealer on the nipple and let it set up a bit before pushing the hose on. I talked to a professional mechanic a little while ago and he indicated that this is a fairly common issue and the RTV trick is often used but it requires a good touch to pull it off. This is because if you go too soon you push all the sealant off the tube and if you wait too long it wont adhere to the inside of the hose.

[erikv11]

Well it's a slow day here but also this one sounds like a no-brainer to me, that's why I didn't respond. If "bumpy and slightly pitted" is even approximately accurate then how about simply smooth out the nipple with wire brush, sandpaper etc, and clamp up a hose.

If access is a hassle for you then maybe a dremel-mounted abrasive would help, just don't go overboard. Replacing that hose would likely help too in terms of getting a good seal, but I know you are basically restoring this car so have likely done that already.

[98v70dad]

Well it's a slow day here but also this one sounds like a no-brainer to me, that's why I didn't respond. If "bumpy and slightly pitted" is even approximately accurate then how about simply smooth out the nipple with wire brush, sandpaper etc, and clamp up a hose.

If access is a hassle for you then maybe a dremel-mounted abrasive would help, just don't go overboard. Replacing that hose would likely help too in terms of getting a good seal, but I know you are basically restoring this car so have likely done that already.

I already did that and its still seeping. It is bumpy and slightly pitted AFTER cleaning it up.

[FLXC90]

Sorry, I was out at a pick n' pull "shopping" for KIA stuff- managed to get one fender marker and harness though, and I know where a SPARE turbo is for my T-5!

After you smooth the corroded area, you could fill it with JB weld kind of stuff and then smooth that as an area to clamp to, that way you build up the area that was eaten away. Once the epoxy is cured it should be a good bondable surface.

[cn90]

Below is a view from behind for Turbo engine.
If you have the Non-turbo model, then the "Turbo Coolant Outlet Hose" part does not exist.

If the nipple is pitted, then you have a few options:
- Use the OEM hose but add a bit of RTV on the nipple beforehand to seal any imperfection....or...
- Find a longer heater hose and goes past the nipple 1" or so...

[98v70dad]

Below is a view from behind for Turbo engine.
If you have the Non-turbo model, then the "Turbo Coolant Outlet Hose" part does not exist.

If the nipple is pitted, then you have a few options:
- Use the OEM hose but add a bit of RTV on the nipple beforehand to seal any imperfection....or...
- Find a longer heater hose and goes past the nipple 1" or so...

Thanks for your ideas and the photo. Its the "nipple" in the far upper right of your picture and it has a raised flange on it so you can't push a longer hose past it. Not really a nipple but I couldn't think of a better way to describe it. Its the hose that comes off the bottom of the overflow bottle. I didn't remember the length of tube before the flange being so long. I could probably get three clamps on that and that might help. Last time I worked on it I was up in the bonnies and I had to work with the one clamp I had.

I may go with the RTV sealant idea but I think most(or all) of it will get pushed off when the hose gets installed. I thought of JB weld too but I think future corrosion and the temperature cycles may eventually pop it off.

I don't think there's a real good solution short of brazing (or maybe soldering) on a thin repair sleeve or an extension. Thats too much trouble for the small problem of a very tiny leak.

[RussB]

Use a new silicone hose. 10mm ID is what you need. It will conform and seal the pitting

[cn90]

And longer hose will go past the ridge on the metal pipe. Add a bit of oil on the nipple so it slides through.

[erikv11]

Use a new silicone hose. 10mm ID is what you need. It will conform and seal the pitting

This is a darn good idea.