Paul,

Could you post pictures of the coolant system pressure tester that I think you and Perry were using to find
the leak in his system.  I thought the local AutoZone store had a pressure tester as part of their Loaner Tool
program but they don't.  Nether did Advance Auto, so I must fabricate one to test my recently rebuilt '87 engine.
I need to determine if I trapped an O-ring and am burning coolant or I'm still burning off the assembly oil.  I fear the
former.

One other thing, the engine "idling" is cycling up and down like a lawn mower.  I suspect a vacuum lean.  Can anyone suggest
where to look for that?

Jim Brewer
Albemarle, NC

PS engine is in a car--tomorrow the sky!

Jim,

Vacuum leaks in cars with computer-controlled usually act in the way you
describe: cycling RPM up and down. The added air leans out the mixture,
the computer injects more fuel, the rpm increases, the computer cuts the
fuel to cut the rpm and the cycle begins, I believe. The whole system
"hunts'" to find equilibrium with the unexpected.source of air.

I've always heard that the way you detect vacuum leaks is to crack the
valve on an unlit propane torch, which you then waft over the various
vacuum hoses. When the burnable propane gets sucked into the vacuum
leak, the rpm will definitely increase. Then you've located the area of
the leak. If you can't find it by inspection,  replace the hoses in the
area.

Do this outside, obviously, on a day that's not too windy.

Those might be some pretty old hoses, with brittle rubber. Hoses I took
off an 88 RX7 were definitely cracked and stiff, sitting atop a hot
engine for those years.

Barry Gardner
Wheaton, IL