Equinox Coolant Leak Playing Hide and Seek and I'm Still "It"

I am trying to find the source of a coolant leak in this 2005 Equinox 3400 CC that leaves coolant in a lower framing member all the way down at the right side of engine, below the alternator. All dry around other likely areas like water pump, radiator, hoses, thermostat. I am fearing a head gasket or intake manifold gasket problem like with my 2000 Buick Regal. What are some of the typical frequent coolant leak problems this particular engine may have?

my (limited) understanding is that if you have coolant dripping externally, that is not a head gasket leak, and probably not a manifold leak.

It has to be dripping somewhere. There is a UV dye you can add to the coolant that makes it easier to see the leak.

If I had it in my shop I’d to a pressure test and see if I could locate where it’s coming from. Common culprits are intake manifold leaks and head gasket leaks. You may not be able to find it because it only does it when it’s completely warm and in traffic or something like that. Do I understand that you are seeing coolant on the back of the engine? Where it mates with the transmission?

I tend to disagree with you . . .

I’ve encountered plenty of leaking lower intake gaskets which leaked coolant externally

But I don’t know if that’s the case here, because we don’t have pictures

The uv dye is a great idea :smiley:

I frequently add it to refrigerant, the green seepage is unmistakable

I bow to your superior knowledge. I thought that leak would cause the fluid to be sucked into the engine.

I was able to get a closer look today. There is a path of coolant running down the rear end of the large cast aluminum housing that the water pump is bolted into. Would this be the timing case? Looks like a gasket is leaking between it & the engine block.

It’s not superior knowledge

Just that I may have seen more externally leaking intake gaskets than you

The timing case would have no coolant flowing to it.

I’m guessing that there is a leak where the water pump mates up, or you have a pin hole leak at a hose and the tiny stream is hard to see. I’ve found a few by turning aff all the lights in the shop and using a flash light…it made the coolant kind of sparkle as the light was passed thru it.


Check the water pump weep holes. There are located on the water pump housing near the shaft (that’s turned by the pulley). There’s often one on top, and one on the bottom. If there’s a noticeable amount of cooling dripping out of one of those hoses, that the sign the water pump requires replacement. The top weep hole is usually easy to see, but to see the bottom weep hole on my Corolla requires some gymnastics. I have to keep trying to see it from different angles, laying on the ground below a jack-standed car with a flashlight, then I can see it.

Thanks for tip. But no coolant coming from under or over pump, or being sling by pulley onto lower radiator hose. So that’s why I had thought the coolant is flowing down under the alternator from a gasket between the block and what I thought might be the…timing chain cover?

Thanks, I could tell the lady to have her mechanic friend do this check for a pinhole leak spraying onto the left edge of what I think is the timing case. I can’t work on it, she returned to her home about 150 miles away this evening.

You may have to remove the alternator for a clear view of the leak to be sure whether it is leaking from the timing chain cover or the intake manifold.

When the intake manifold began leaking on my son’s 3.4 L Pontiac it was leaking at the rear of the engine and puddled on the transmission bell housing, easy to see. For a leak at the front of the engine you will need to remove the alternator and power steering pump to perform the repair so why not remove these for inspection?

Makes sense, I will tell the lady to have her mechanic do that, thanks.