Truck is a 2001 Supercrew 4x4 with the 5,4

The coolant leak is somewhere I really cant see it just the liquid it leaves on the ground. I would say on the rear of the engine on the passenger side. Weird thing is it only leaks when its colder outside and I first start the truck to let it warm up. Once the engine has been running for 10 minutes or so it stops and it will not leak again until the next day. I though it might be the heater hose from the core to the front of the engine. That was no it, Just looking for some suggestions as its driving me crazy.

Thanks in advance

Marty

 

I would try a coolant gases test or Hydrocarbon test on the coolant. Most parts stores should have them.
If this turns up positive, then there is a good probability that you need head gasket replaced. Or you can pressure test the coolant system.

 

 

Not necessarily. That will only happen if it's leaking between a coolant passage and an oil passage.