DIY to leak test heat exchangers with water and air, So you don't suffocate someone with exhaust fumes.... Options

[SpecialInt]

I have some SS heat exchangers for sale and someone asked if I had tested them for leaks. I had not. A few people chimed in with some procedures to test them. Thought I would document my test so anyone selling a set could easily check for leaks.

Needed.
1 valve stem. Long for alloy wheels.
1 one x six or similar
6 bolt
12 washers
6 nuts
Some gasket material/ pond liner/ vinyl or similar

You can get rubber plugs from Home Depot or make the with the items below.

Home made plugs
4 lg fender washers
4 med fender washer smaller than exhaust tube at head.
4 small rubber washers
4 lg o rings
3 bolts/nuts

Some basic tools.

Cut some gasket material to fit the muffler end of the exchangers.
Place it against the flange and mark the holes.

Punch out the holes

Place the 1x6 against the exchanger flanges.
Mark the holes
Drill the holes where marked

Bolt the exchangers to the wood

Fill the exchangers with water. Make sure you lift the head ends up where you fill the so they are full or close to full of water.

Insert the plugs. If you made some like I did you will need an air gun to tighten them since you can't hold the nut.

Insert the plug made with the valve stem.

Lay them flat on the floor.

Use about 20 PSI at the valve stem.

The flanges started leaking at the gaskets but the heated air ducts showed no signs of leakage