Mystery coolant leak ... how to locate ?
 

Just finished an engine install but I have a coolant leak from turbo banjo connections that should hopefully be easy to find + fix with new crush washers.
I just need to pull the downpipe to fix that leak I'm hoping.

There is also a leak from the engine/radiator side.
I have isolated turbo coolant lines from engine lines to help diagnose each leak seperately.
The engine/radiator portion loses 1 gallon or about half of it's 2 gallons of coolant before the leak stops. The leak is from the left passenger side of the block and leaks to the ground between the engine and surrounding subframe.

I haven't investigated beyond pulling the air ducts above turbos yet
and frankly reluctant to pull it all apart.
I'm guessing from the amount of coolant lost the leak must originate from a lower
hose bung on the water pump/coolant tower.
I had to put this build on hold because I'm broke and frankly fed up with the project ATM.
It's been a year of setbacks + waiting for parts ... not for timid shadetree types like myself. :)

Hindsight is 20/20, but I wish I'd tested coolant and oil systems using air
pressure prior to installing the engine/tranny.
It would have made everything so much easier !
I'll fill it with water + recheck for leaks in about a month when chances of freezing overnight weather are diminished.
No engine or tranny oil leaks yet, but I haven't started the car or brought it up to operating oil pressures yet.
Original JDM pinch type hose clamps were used for every connection.
The only corroded brass bungs were under the throttle body and the turbo coolant return line between front turbo + engine block.

Any sleuthing tips, suggestions, or sharing of similar experiences would be much appreciated.

Thanks

Theres not that many places that can leak. off the top of my head these are the possibilities

Turbo feed & return on turbo itself, and also engine block.
Block to radiator
Radiator back to block.

Rear iron to throttle body. Throttle body to front iron.
Heater - engine to firewall.
Heater - firewall back to engine.
AST or AST delete to overflow tank.

that's about all of the connections I think?

If you're losing a gallon of coolant that should be super easy to find. Go rent a coolant pressure tester from an auto parts store. Once you pressurize the system it should be apparent where the leak is.

Matt

Double post

You can re-use copper crush washers, but you need to re-anneal them first. They have been work hardened by compression.

Take a propane torch and heat them to a dull red-hot. Let them cool. They will go from being impossible to bend in your fingers to soft and malleable so you can bend them with your bare hands.

Definitely a job for a pressure tester.

Thanks guys.

I'll refill with water and try adding air pressure at throttle body inlet with an air pump
which should hopefully make the lower leak more obvious.
The strange thing on the engine/radiator portion is that it held air pressure when I tested it
prior to adding coolant and now it leaks coolant, albeit very slowly ???
I used less air pressure than the rad cap is rated at.

I already have the turbo inlet crush washers, but very good info for when we don't have spares, thanks Alex.