Actone for identifying a crack

[superfets]

I have a 3.0 l mercruiser with what i suspect is a cracked intake/exhaust manifold. How long does the acetone take to creep through the crack? 30 minutes or 12 hours?

Cheers and thanks

 

[harleyman1975]

it goes through pretty fast.

 

[flipbro]

If it's cracked it would be seconds.

 

[superfets]

Ok. I bought a bottle of acetone and poured it in the manifold on the exhaust side and saw no sign of a leak for a half hour. I was pretty sure it was cracked but my brother said it looked like a casting defect. And after hitting it with a scotch pad on the grinder I think I may be ok.

Thanks

 

[HT32BSX115]

Another way to check a manifold is to pressure check it.

Make yourself a manifold-riser block-off plate out of thin aluminum, copper flashing, etc...... and make 2 gaskets to sandwich the plate. Apply sealant to plate, gaskets and bolt it together. Torque to spec. Pressurize the manifold to 15-20 PSI, use a 0-30 psi gage and a valve so you can shut it off. See if it holds pressure.

I used an old closed-cooling block-off "plate" and home made gaskets to pressure check one of my 7.4L manifolds. It held 20 PSI for the entire day.