As I noted in a parallel thread I got the valve out today. Just finished studying it mm by mm under a loupe for a tiny crack allowing slow driving leak under high pressure.

I see 3 suspect areas. This got me wondering, let me explain.

I can't think of a way to pressurize it for a test (how to connect my compressor to a 3/4 OD port). But was thinking of attacking proactively reinstall and retest.

Area 1. This is a 2 piece manufactured item. The seal at the seam is suspect.

Area 2. Suspect long thin area on the port branch.

Area 3. Under magnification a tiny area looks cratered.

As I thought about it, all of these areas are easily patched, but which path to take? Lord knows, the experience on this site is so varied i figure I'd ask.

Anyone know if black plastic like this will respond well to PVC cement used in plumbing?
Or
Should I just pull out the plastic welder and weld right over these areas?

I'd love to hear what you think. In the meantime I'm going to cover the outside in talc powder and see if I can add air pressure to reveal the leak area.

John

 

Depends on the plastic. I have recently been doing some bumper modification and have come to learn that polyurethane cannot be glued with solvent weld cement or with heat from a welder because it is thermoset plastic.

I would pressurise it like you said and spray some gas leak detector spray (another plumbing shop consumable) all over it to identify where the leak is.

Depending where the leak is you may be able to repair with something like sikapower 2955

 

Thanks! My brilliant idea using powder was a bust. No Einstein award for me.
Probably not worth repairing it.

If you might know of one of those plumbing 1 way valves, its 3 1/3 inches long, 3/4 inch OD pipes on either end. This is a duplicate of what I wrote in the other thread, not rushing you, just figured you'll see this faster easier.

John

 

John,
Please, please only fight the battles you're going to win.

Thermosetting plastic might be open for repair where there's no risk of consequential damage, which is not the case here. Either:

1) Take up RJ's offer of his spare valve;
2) Find a plumbing non-return that's guaranteed to work with temps - i.e. not yer 'garden hose' type fitting;
3) Hire a car until the new octopus arrives.

Apologies for the lecture mate, but I'd hate to see you reporting back in a few days that you have dropped valve seats/warped head(s)/Nikasil shavings in your oil pan.

 

I did see the other thread and will check tomorrow. I don't think the sizing is an issue but as Michaelh has mentioned the temperature may be. This sort of fitting in a plumbing situation would be used for boiler condensate or a hot water cylinder blow off so will like be OK for 70 degrees C but car coolant usually gets up around 100 degrees C I think so a plumbing part may not be tested to this temperature. I need to check the specs.

 

XKOwen,

Thank you so much. RJ was kind enough to offer me a spare jaguar valve he has, I really appreciate your offer, but it looks like I'm covered now. I appreciate you and everyone else who's jumped in to help here.

John

 

No probs, glad it is sorted.

A plumbing shop can be a very useful place when fixing cars 😄 I have used all sorts of connectors and clamps when fixing my car. My headlights have a couple of toilet seat fixings stuck underneath with epoxy resin as replacements for the metal lugs that rusted to the retaining bolts. Much cheaper than new headlights!

 

There MAY be a code molded into the plastic indicating the type of plastic it's made from. If you can find the code you can research the types of adhesives/repair techniques best suited for it. This link might help

https://en.wikipedia.org/wiki/Resin_identification_code

A lot of the automotive plastics are polypropylene, which are virtually impossible to repair with adhesive.

This is also from wikipedia ...

Repairing[edit]

Many objects are made with polypropylene precisely because it is resilient and resistant to most solvents and glues. Also, there are very few glues available specifically for gluing PP. However, solid PP objects not subject to undue flexing can be satisfactorily joined with a two-part epoxy glue or using hot-glue guns. Preparation is important and it is often helpful to roughen the surface with a file, emery paper or other abrasive material to provide better anchorage for the glue. Also it is recommended to clean with mineral spirits or similar alcohol prior to gluing to remove any oils or other contamination. Some experimentation may be required. There are also some industrial glues available for PP, but these can be difficult to find, especially in a retail store.[66]

PP can be melted using a speed tip welding technique. With speed welding, the plastic welder, similar to a soldering iron in appearance and wattage, is fitted with a feed tube for the plastic weld rod. The speed tip heats the rod and the substrate, while at the same time it presses the molten weld rod into position. A bead of softened plastic is laid into the joint, and the parts and weld rod fuse. With polypropylene, the melted welding rod must be "mixed" with the semi-melted base material being fabricated or repaired. A speed tip "gun" is essentially a soldering iron with a broad, flat tip that can be used to melt the weld joint and filler material to create a bond.

Hope this helps.