Mystery milkshake after pan gasket change

[Instigator01]

Hello,

New member here and of course looking for some help or guidance.

2001 denali LQ4 317k miles.

Swapped front diff due to some heavy chatter when pulling my boat. I thought what a great time to change the oil pick up o ring and pan gasket. I took my time and was very careful about each.And every step, including thoroughly cleaning the oil PAN and mating surfaces and reinstalled.Everything which seemed to go smooth no.Issues.

Refilled with oil and fired it up.Sounded great went for a quick test drive.Oil pressure was fine by the time I went a mile and back home.I had a serious rodknock. Did a quick search on YouTube?Most ideas were maybe somehow some.
R t v got sucked up into the oil pick up.

So here I am starting the whole process over again to remove the PAN as soon as I drain it, out comes fresh milkshake. I'm stunned I can't believe there's water in my oil. Seem like a lot too.Maybe an extra two or three quarts anyhow.

When I drained the oil to do the PAN gasket, the oil was black and fine.There was no indication of water in the oil.

 I carefully did the repair.And I am at a loss to how that coolant got in the pan. I didn't touch anything else on the engine.Only the oil cooler lines and the removal and installation of the front diff.

Now I'm getting ready to install a long block.And I don't want to run into the same problem.Can you guys tell me where to look to figure out after this seemingly simple repair?I ended up with a dead engine and an oil PAN full of coolant.I have no idea how it got in there.

Any help would sure be appreciated!

Thanks

 

[the 18th letter]

WAG but double check the cooler lines maybe?

 

[89Suburban]

That blows, sorry man.

 

[Larryjb]

Could be a cracked head. It may have just let go. It is common on these years.

Pop the valve covers off and look for a "clean" section by the head bolts. Below is a thread showing what my head looked like.

Latest oil change/ oil filters

I just pulled the valve covers to inspect the head. It is not a Castech, BUT it is cracked in the same position that the Castech heads were cracking. Time for new heads. In the oil drainback hole you can see the crack before I pressurized the cooling system. I already cleaned the area for...

www.tahoeyukonforum.com

 

[Instigator01]

It crossed my mind, but it is too coincidental to The timing of the repair.


The engine still runs absolutely perfect.No misfires no check engine lights, idles completely smooth.

As I pull it apart, I'll be checking in take manifold gasket. And I might be left with no choice but to change the oil cooler/radiator Just to be sure they're not corrupted.

Is there some way the water pump could have failed and dumped coolant down the front of the motor into the pan?

 

[Donal]

Hello,

New member here and of course looking for some help or guidance.

2001 denali LQ4 317k miles.

Swapped front diff due to some heavy chatter when pulling my boat. I thought what a great time to change the oil pick up o ring and pan gasket. I took my time and was very careful about each.And every step, including thoroughly cleaning the oil PAN and mating surfaces and reinstalled.Everything which seemed to go smooth no.Issues.

Refilled with oil and fired it up.Sounded great went for a quick test drive.Oil pressure was fine by the time I went a mile and back home.I had a serious rodknock. Did a quick search on YouTube?Most ideas were maybe somehow some.
R t v got sucked up into the oil pick up.

So here I am starting the whole process over again to remove the PAN as soon as I drain it, out comes fresh milkshake. I'm stunned I can't believe there's water in my oil. Seem like a lot too.Maybe an extra two or three quarts anyhow.

When I drained the oil to do the PAN gasket, the oil was black and fine.There was no indication of water in the oil.

 I carefully did the repair.And I am at a loss to how that coolant got in the pan. I didn't touch anything else on the engine.Only the oil cooler lines and the removal and installation of the front diff.

Now I'm getting ready to install a long block.And I don't want to run into the same problem.Can you guys tell me where to look to figure out after this seemingly simple repair?I ended up with a dead engine and an oil PAN full of coolant.I have no idea how it got in there.

Any help would sure be appreciated!

Thanks

"When you refilled the engine with oil." Another likely source is that the oil jug had been used to hold antifreeze.

 

[Instigator01]

I wish that was the case.

 

[Instigator01]

 

[Instigator01]

Looks like I found the problem.Driver side water pump connection was leaking.You can see in the picture how it's cleaned the front of the timing chain cover.

I must not have got the pan gasket on correctly And coolant leaked into whatever gap there might be.

Still seems odd.There was no sign of coolant leak but it seems the picture shows It might have been a pretty steady flow.

Once I Pull the motor I'll inspect that pan gasket and see where I screwed up.

Seems like the only way coolant could have got into that pan.

I will do a follow up once I get more information.

Anybody have any thoughts?

Thanks

 

[89Suburban]

View attachment 428489View attachment 428488View attachment 428488View attachment 428488View attachment 428488View attachment 428489

What are we looking at here? Broken water pump bolt?