Leaking coolant

My '99 GT is leaking coolant from somewhere, and I can't seem to figure it out. Some of it seems to settle on the lower intake (before running onto the ground), so I can't tell if it's coming from the water pump (doubt it), the timing cover gasket, or the upper intake (maybe the plastic is cracked). I went to a mechanic and he put some pressure on it, but he couldn't find any leaks. It's not a consistent leak either. It'll happen for a few days in a row, then stop for a couple of days. Has anyone else run into this same issue? Thanks in advance for your help.

Check the heater hose from the water pump (located in the engine valley). Also, the plastic coolant crossover in the intake manifold is known to crack. However, you can rule out the timing cover since no coolant would leak through it since only oil is behind it.

If your intake is ALL plastic remove alt to look for crack. updated manifolds have a aluminum runner in the front for coolant. Changed one last week.

Originally Posted by gbic1

If your intake is ALL plastic remove alt to look for crack. updated manifolds have a aluminum runner in the front for coolant. Changed one last week.

The 96-early 01 cars have full plastic manifolds and they tend to crack and break. That is more then likly the problem. They have a TSB out and they replace it with the 02-04 GT manifold which has a metal coolant crossover in the front so it wont crack.

I dont know if your into modding this car, but its a good time to do the "coolant mod" if you are going ot add more power. If you dont know what that is i can explain more.

I believe it's all plastic (completely bone stock '99 GT). The mechanic I know told me he thought it was the intake, but after he put some pressure on it, he couldn't find a leak cause it's not leaking consistently. I feel pretty sure though that it is the intake. I haven't put much thought into mods for it spikeafrica, but I'm always willing to listen to any options. Thanks for the help y'all!

More then likliy its like all the other plastic manifold cars and is leaking from that front coolant crossover.