Intermitant coolant leak

[daveccpa]

So I noticed a small amount of coolant leaking from underneath the car a few weeks ago . The puddle was behind the drivers side door. It was maybe 1/4 cup. I took the car to my mechanic who looked it over and couldn't find anything leaking. He checked all the hoses the radiators, the water pump etc. He suggested I replace the coolant tank cap which I did. He drove it for a day and couldn't find any more leaks.

I drove it for a few weeks as well with no problems. Then my wife takes it on an extended drive on Saturday (about 75 miles) and on her way home the temp light starts flashing. She pulls off and adds coolant and drives the rest of the way home without problem (20 miles). The temp never got about 185 so I think she got it before any damage. When she parked it there was a small amount of coolant leaking but stopped once the car was off.

There is no leaking in the trunk that I can see and the trunk is dry. However, I'm thinking it probably is the tank. Does these tanks when they do leak have intermitant leaks or do they just crack and drain.

[Mark at Pelican Parts]

Welcome to 986forum!

But you replaced the tank so it should be new?

[tommy986]

Yes, the tank leak can be intermittent depending on temp.
Mine did basically the same thing.
You need to remove the trunk carpet to actually see where it leaks into the trunk.

[mgfranz]

I have the same problem! An intermittent leak that only happens on about 20% of the drives I make. Small coolant puddle just before the driver side wheel. I checked the cap and pulled the trunk carpet but could not see anything. I pulled the driver side vent and didn't see any accumulated water in the cup, but it looks like there had been some previously. I pulled engine covers and drove for a bit, came back and got under but didn't see any leaks. So now I'm thinking I might just have a bad, or going bad cap.

[Steve Tinker]

How can a bad cap (located in the passengers side trunk area) cause a puddle in front of the drivers side wheel?
There is no coolant line close to the drivers side engine air vent.

[woodsman]

There's an overflow hose that exits in front of the pass side rear wheel.

[Steve Tinker]

Agreed - perhaps the op is driving a right hand drive car in So Cal......

[woodsman]

The oil cooler is on the left side of the engine and it has coolant flowing through...

[daveccpa]

Mine was a cracked coolant tank. I think when the pressure in the system built up it caused the cracks to open and thus leak.