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?

 

[89Suburban]

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

I don't see how that is possible. But these days nothing surprises me anymore haha

 

[Instigator01]

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

No, all the bolts came out intact. Appears it's a gasket failure.

 

[Instigator01]

I don't see how that is possible. But these days nothing surprises me anymore haha

It's all I can figure and there's clearly a leak on the driver side connection point on the water pump.

The passenger side connection is completely covered in Grease, whereas the driver's side has been washed.Clean from the leak.

The only other thought I have is.The coolant is leaking behind the timing chain cover into the pan.

I will know more once I get it pulled and tore apart.

 

[89Suburban]

It's all I can figure and there's clearly a leak on the driver side connection point on the water pump.

The passenger side connection is completely covered in Grease, whereas the driver's side has been washed.Clean from the leak.

The only other thought I have is.The coolant is leaking behind the timing chain cover into the pan.

I will know more once I get it pulled and tore apart.

I don't think that can be happening either but I wish you the best. Are you loosing coolant in the overflow tank? Like a measurable amount?

 

[Instigator01]

I don't think that can be happening either but I wish you the best. Are you loosing coolant in the overflow tank? Like a measurable amount?

Overflow tank was dry but the top hose on the radiator spilled fluid when I disconnected it..

Drained the coolant and it had no oil in it.

That leak is the only evidence I have of water intrusion into the pan. The only other thing I could figure is.The oil cooler had ruptured and filled the oil cooler lines with coolant.But that doesn't appear to be the case.

There Was no coolant in the oil until I changed that pan gasket.

 

[Mudsport96]

I would pressure test the oil cooler in the radiator before starting the new engine. I know it seems coincidence that it could have let go right after fixing the oil oring. But that really means even if you did not do that work, it was going to let go the next time you went driving.

 

[Instigator01]

I would pressure test the oil cooler in the radiator before starting the new engine. I know it seems coincidence that it could have let go right after fixing the oil oring. But that really means even if you did not do that work, it was going to let go the next time you went driving.

I.
Would have thought if there was a corruption in the oil cooler that the oil would also be mixed with the coolant.

 

[89Suburban]

Do you have a picture of the contaminated oil pan we can look at?

 

[Instigator01]

Do you have a picture of the contaminated oil pan we can look at?

No it's still on the motor.

Little good news for me though, I was just able to loosen all three torque converter bolts.

The first one was rough but then the next two went well.

All the YouTube videos show using a socket and everybody rounds off those bolts. But I've never seen one. YouTube video where they actually used a hex key socket, which is what I did. I didn't even have to hold the flywheel, still. Feeling lucky now!

I'm gonna call it a day for now and yank that motor tomorrow

Thanks everyone

 

[89Suburban]

No it's still on the motor.

Little good news for me though, I was just able to loosen all three torque converter bolts.

The first one was rough but then the next two went well.

All the YouTube videos show using a socket and everybody rounds off those bolts. But I've never seen one. YouTube video where they actually used a hex key socket, which is what I did. I didn't even have to hold the flywheel, still. Feeling lucky now!

I'm gonna call it a day for now and yank that motor tomorrow

Thanks everyone

Why do you have to unbolt the converter?