Pressure-Testing Heater Core

[thehackmechanic]

I was about to reassemble the heater box when I realized I hadn't pressure-tested the core. I read online about cutting an inner tube, hose-clamping it onto the pipes, inflating it to 5psi (yup, low pressure -- this ain't an evaporator core), dunking it underwater, and looking for bubbles. Voila!

Plus, as a bonus, you get the "WHAT IS THAT IN THE SINK?" effect on your wife!

[Scott Sislane]

What a great idea. Thanks for sharing Rob-

Scott

[Mikesmalaga72]

+1 on that one!

Get some CLR or similar and de-lime it and recheck IMHO..Thanks.

[Hans]

I think you wife should write the sequel to your book. My Life with the Hack Mechanic. So did it leak?

[thehackmechanic]

<>

My wife? No, tight as a drum.

BOOM!

Sorry.

(It did not leak. The heater core.)

[BillWilliams]

Great idea. Are you going to clean it out somehow?

[TobyB]

Ha! That's so much quicker than the fittings I jury- rigged to do that job.

Neat!

Plus, there's a lot lower danger of accidentally pressurizing it to the 90 psi of the compressor....

...but I'd go to 15 psi, myself- I found that some cores can crack at the end

tanks, and the cracks only really leak when you're running the same

pressure as your radiator cap.

t

[thehackmechanic]

Toby, so 15psi is good? Things I read online at other sites said 5. I didn't think to tie it to the cap pressure, but that makes sense. Thanks!

[Napes]

Glad you included the picture - I was trying to imagine doing this with a car tire innertube. Didn't even think of a bicycle innertube. But, my confussion notwithstanding, that's a good idea.

Bob Napier

[Mike Self]

Bet you could do the same thing to test a radiator with a length of plastic plumbing pipe, two pieces of inner tube and four hose clamps. Install the cap and pump until the cap pressure released.

mike

[Kidasters]

Just be careful.

Remember - with 5 psi, the inner tube won't grow that much. With 15 psi, it will grow more. If you want to test higher than 5, I'd build something with hose that won't expand and some fittings.

I agree with the "clean then test" theory. Crud will hold a lot of pressure.

[dbmw2002]

Hack, thats what I call thinkin like a German, the longer we are at this the simpler it becomes

[thehackmechanic]

So how do you pump up the tube to 15 psi when a tube without constraint (ie, outside of a tire) will blow up at 15 psi?

Constrain it.

Packing tape.

[jimk]

Keep your face away from that tube with it pumped up. If it blows it will slap the hell out of you along with a possible hose clamp on it's end.

[TobyB]

Packing tape

Yipes! Not duct tape???

I'm with Jim, that thing scares me!!!

And yeah, Rob, I found a core that had cracks in the end tank (maybe it froze?)

It held both water and air at 5 psi, but at the 13ish of the cap, the cracks would

ooze coolant.

So now I test at 15, and if it explodes, then it was never meant to be.

heh

t