Coolant flange leaking dont know how to fix

[slybunda]

iv cleaned up the engine block area where the flange fits and noticed its pitted in some areas and one area had a deepish pit in it where i think its been leaking from. the o ring on the old flange looks bad and also looks like part of the flange may be broken.
iv attached pics, i dont know if the new flange and o ring will be enough to seal or what can i do about that pit which i have circled in red?
thanks all

 

[CarbonSteel]

Ouch! You could add a 1/8" thick aluminum or stainless plate between the new neck and the block and use a gasket and silicone on the block side to seal the leak. Be careful with the threads in the block as they are aluminum. You may want to use studs instead of bolts.

Hope this helps!

 

[kschachn]

Also there are some two-part epoxy putties that are used to repair aluminum like that.

 

[andyd]

I use Permatex Aviation Forma-Gasket # 2 for pitted aluminum.For a really deep gouge, maybe some JB Weld. That neck is beyond help and its condition tells me you're not changing your coolant very much.

 

[ragtoplvr]

Defcon metal filled epoxy. Then when just about cheese hardness use Stanley Sureform to flatten. Let set up, file flat. See if you can get a new hose neck.

Rod

 

[kschachn]

Originally Posted by ragtoplvr
Defcon metal filled epoxy. Then when just about cheese hardness use Stanley Sureform to flatten. Let set up, file flat. See if you can get a new hose neck.

That would be Devcon metal filled epoxy I believe, not Defcon.

 

[slybunda]

its a vw corrado g60 around 30 years old. was bought about 3 years ago but not driven much, had little history and im guess the previous owners did no do coolant changes on time or at all.
i dont know if due to pitting im gonna need more clamping force or something but since the flange is plastic i cant risk it. would i be better off getting one of these as a replacement:

 

[slybunda]

ok after hunting around looks like i cant get the aluminium one in the uk so plastic its gonna have to be. the above suggestion for jb weld maybe something i can look into.

 

[Trav]

Regular JB will be fine for that job, with a new flange it should be all set. Use some Hylomar under both sides of the O ring.

 

[JimPghPA]

Fill the pit with JB Weld epoxy and press a piece of wax paper against it to get a flat outer surface and let the wax paper on it until the next day. The wax paper will peal off easy and leave a flat finish. You may have to sand it or take a flat stone or fine file to it to finish it.

When you put the wax paper on it look for air bubbles trapped between the wax paper and the epoxy. If you get an air bubble you may be able to get rid of it by putting a pin hole in the wax paper.

You are lucky that you are doing this in the summer. JB Weld will not set up if it is too cold.

 

[Colvin]

Find a welder that dose aluminum welding, he should be able to fill it then smooth it down. That's really the only permanent fix.

 

[Dave9]

Be sure to wire brush and solvent clean the pits before putting epoxy in. However once you've done that, epoxy probably isn't needed, just some silicone RTV, laid on and then a squeegee to scrape-level it off, then let that cure before reassembly. Epoxy can last longer but depends on a cleaner surface to do so, otherwise will more readily crack off. Plus many of the putty type epoxies have terrible adhesion, you might want to squeegee compress those in too.

 

[slybunda]

cropped the pic but need to get a proper macro shot to see it in detail. im getting the o rings ordered in so have time to sort the car out.

 

[slybunda]

would something like this work: https://www.ebay.co.uk/itm/85g-MANN...ant-High-Temp-Sealant-300-C/202779518720
??

 

[andyd]

Maybe. JB Weld works great with aluminum RtV will work but its excess can clog stuff IIt takes time to cure too. Forma gasket skins over and you assemble it ,Done. I also coat threads in aluminum.with it.

 

[slybunda]

Do you have a link for this forma gasket?

 

[andyd]

https://www.autozone.com/sealants-g...2-form-a-gasket-sealant-3oz/526681_0_0?s

It is virtually the same as Hylomar only cheaper and more widely available over here. The Aluminum necks were pitted on my 528e. No matter how much I tightened the clamps. I was getting green fuzz. from weeping coolant. Pulled the hose off. Neck is pitted all over. Gooped the entire neck . Hose slid back on and never leaked again. It is non hardening, so the hose comes off easily too. Older tech than RTV

 

[Trav]

He is in the UK, Hylomar is probably cheaper because its made there and readily available.

 

[slybunda]

Yes i saw hylomar is easy to get and price is decent. Got stuff on order. Will let you know how it goes.

 

[nobb]

Luckily you still have enough meat on the surface such that even if you were to use a standard paper gasket, it would still probably seal ok. In this case, I would clean the gouge really well, fill it with JB weld, sand the entire surface flush, and use a paper gasket (to make things easier to service next time). Oh, and change the coolant more often!