I have been searching all day and can't find anyone with this problem. While the engine is running there is no leak. When the engine is cut off for a few minutes coolant starts leaking on the passenger side behind the engine. It leaks a 1 or two cups of coolant and stop. I can't see where it is coming from. I did loop around the heater core to eliminate it as a possibility. Any ideas??

95 4Runner V6 3VZ-E
original head gasket
211,000 miles

 

 

Thanks Bob, great picture. I am 90% sure that's not it but I will watch it again tomorrow to make sure.

 

It is not the hose. The leak is below that somewhere I can't see. Today it did leak a little while driving then stopped. When I cut it off it did not leak as it was doing. I wish it would at least leak consistently.

 

Your best bet is a cooling system pressure tester, with an adapter for the radiator. This will help you locate the leak when the system is cool.

 

I'm having the EXACT same issue. Only leaks bad when stopped but with the rear window down i can smell it even when im on the highway.

93toyrunner is probably right about the hose he posted in that picture. There isnt much on the back of the engine that carries coolant other than that piece and the coolant crossover for your heat core and throttle body.

Can you run this pressure test with the upper intake removed to better see the hoses back there??

 

I have a similar problem with coolant leaking when the engine is off - I had to replace the bypass hose a couple months ago, but this time the leak is in the front of the engine.

The car will sit in the drive way for 3 days - one day nothing, and one day it will leak. Water pump has now been replaced twice in the last 10 months...Once two weeks ago, and once 10 months ago..

They replaced my water pump - (Part was warrantied) and it's still leaking..They said my headgasket is leaking some, and valve cover gasket, but what else could it be...did they not get the water pump sealed?? Water pump was just done two weeks ago.

 

Hoses swell when hot, shuts off leak, cools down, contracts and leaks.

Pressure test the system. You could guess until hell freezes over.

:wabbit2:

 

I know this thread is several months old, but that U hose is part 16267. Im having the exact same leak.. not sure like many other if it is coming from the U hose or not. Going to replace that but want to know if it could be the coolant intake manifold that the U hose plugs into part 16351? It has a part 16347 as a gasket to the coolant intake manifold but what is the likely hood of that gasket going bad? I will know for sure after this weekend if it is the hose or not.

 

I had the same type of leak last year, but it would show up on both sides of the engine at the back, it was my intake manifold leaking. Would only be visable when the engine was not running, this may not be your case, but its something to check.