1978 Vintage A4 Exhaust Manifold

[sgblume]

Greetings picked up a used replacement, and have begun preparing it for installation. Discovered fouling in the water inlet/outlets once I pulled the fittings off. Used the famous coat hanger trick to start breaking things up. Going to try to hook a hose to it today and run some warm water through it. My question is whether this can be boiled out similar to a Radiator or like when I did my Monel fuel tank?

[jpian0923]

I think a Muriatic acid flush is the quickest way. Refer to Overhaul manual for the correct procudure ( I can't recall it off hand). It worked wonders on my exhaust mixing elbow complete blockage, but it took a month of soaking to clear it.

I defer to others on the boiling technique, never did it myself.

Also, if raw water cooled, I'd suspect the fouling at the fittings are marine growth related...which muriatic acid is great for dissolving.

[sgblume]

1978 Vintage A4 Exhaust Manifold

My Pearson 28 has been drinking fresh lake water for the last 6 years, however, I purchased the manifold from a guy in Houston who is scrapping out old A4's after the last hurricane went through in the Galveston area, so I do suspect that the problem is rooted in the affects of salt water.
I plan to take it to a radiator shop this week to have it flushed with muratic acid then boiled out just to make a fresh start!

[Mo]

The rad shop will do a good job for you. They will rinse it out and all that...should be good to go once they are done with it.

[hanleyclifford]

Wouldn't hurt to do a pressure test on the water jacket before installation--just in case...