Coolant leak back of engine down oil pan, driver side

[InspectahDEck]

@treehan77 Does that run inside the firewall to the driver side? Would that be accessed behind the instrument cluster/ dash?

 

[treehan77]

The T connections are a little toward the passenger side and very common to leak, there’s 2 of them

 

[InspectahDEck]

@treehan77 Yeah that's what I replaced two days ago. It was leaking there on the white T, but after fixing that, and confirming that area has stayed dry, is when I started looking it this further. The white Tee was visibly leaking (I could see it drip every 10 sec or so), so I did not bother to think there was a second leak somewhere.

After fixing that and the leaking continued, I got under the vehicle and can see coolant on the driver side of the oil pan, going up towards the back of the engine.

Digging around, I have seen mention of freeze plugs having issues. Are there freeze plugs up there that I can visibly see with an inspection mirror or similar before I commit to taking off the heads?

 

[strutaeng]

@treehan77 Yeah that's what I replaced two days ago. It was leaking there on the white T, but after fixing that, and confirming that area has stayed dry, is when I started looking it this further. The white Tee was visibly leaking (I could see it drip every 10 sec or so), so I did not bother to think there was a second leak somewhere.

After fixing that and the leaking continued, I got under the vehicle and can see coolant on the driver side of the oil pan, going up towards the back of the engine.

Digging around, I have seen mention of freeze plugs having issues. Are there freeze plugs up there that I can visibly see with an inspection mirror or similar before I commit to taking off the heads?

Yes. There's a large Allen head brass on the driver's side and a smaller one on the passenger side (have to remove the starter to see it) IIRC.

I think both a lower on the engine though. I don't believe the leak would show up behind the the transmission bellhousing(?)

Can you go rent a coolant pressure test kit from the local parts store? Pressurerize the system them go looking for the leak. I think there's even some dye you can add to help locate leaks?

 

[InspectahDEck]

I do have dye in the coolant, which in my second video of OP shows where it's dripping from, but that's about how far up I can see.

Would a head gasket combustion leak test kit work? If not I can try and rent a pressurized tester

 

[strutaeng]

I do have dye in the coolant, which in my second video of OP shows where it's dripping from, but that's about how far up I can see.

Would a head gasket combustion leak test kit work? If not I can try and rent a pressurized tester

Ah, ok. No wonder the coolant looked kinda bright?

You can try the combustion leak test, but that will only tell you if you have combustion glasses mixed into the coolant; you seem to have an coolant leak externally.

Your truck runs okay? No overheating, rough idle or gurgling on the coolant tank?

Was that you that created the recent thread about a leaking thermostat housing? Maybe I'm getting confused with that thread?

I have an engine block in my garage. I'll take some photos shortly so you can see the water passages and maybe that will help you...

 

[InspectahDEck]

Your truck runs okay? No overheating, rough idle or gurgling on the coolant tank?

Yes runs fine, have not noticed anything out of the ordinary.

Was that you that created the recent thread about a leaking thermostat housing? Maybe I'm getting confused with that thread?

Yes that was me. I have sprung multiple leaks out of the blue within the last month. It started with the thermostat housing, I replaced that gasket and was still leaking. Then I saw it was leaking from the heater hose tee, so I replaced that. No I'm leaking from the back of the engine somewhere... I suppose they are all possibly related, but it's been one thing after another.

I have an engine block in my garage. I'll take some photos shortly so you can see the water passages and maybe that will help you...

I would appreciate that tyvm

 

[strutaeng]

Here you go. Those little "V" looking things on the deck are the coolant passages.

You can also see the Allen head coolant core plugs.

Try to get an inspection mirror so you can see the mating surface between your block and the heads. Maybe it's leaking from there?

 

[Fless]

Maybe the coolant crossover?

What is this part that is leaking coolant?

I have a coolant leak that I thought was from the thermostat housing, but after replacing that and the thermostat the leak continues. The thermostat area is completely dry, so I added some dye so I can find the leak easier. It seems to be pooling from the area circled red, I also included some...

www.tahoeyukonforum.com

 

[InspectahDEck]

@strutaeng Awesome, very helpful. I'm going to run and buy an inspection mirror so I can try and get a better look.

@Fless I just recently put new gaskets on the crossover at the front and am not seeing any leaking there (is there one on the back?)