Issue Replacing Water Pump

[ChrisW]

2008 6.2L Yukon Denali 182K
Replacing factory water pump.
The bolts I removed won't go back in.
They thread ok; I can even start them by hand, get them tight very quickly, and don't want to tighten all the way down.
I don't want to force and strip them.
Even tried without the water pump. Same result, they will start but get very tight just a few turns in. I tried multiple bolts in different holes. Same result.
If I wiggle them a little, I can get them to turn a little more.
But you can still see the "used" part of the thread not going all the way in.
I inspected the threads; they all look ok.
I do notice that the last few threads look shiny.
I am going to clean them up with a wire brush on a Dremel and inspect them better.

I did try to search for this, but didn't find anything.

Also, while I am at it, I am replacing the idler pulley and tension pulley. There were only the top 2 bolts on the tension pulley, but there are 3 holes. Have I lost one?

Any help is appreciated.

Thanks Chris

 

[strutaeng]

Are your bolts rusted? They'll usually have a bit of rust on the GMT800s I've done in the past, but not horrible. Wire wheel them and that's all I've done. You can always replace them if they are fighting you.

In the past, I didn't know better and added some thermostat sealant on the bolts (like on the SBC, where the water pump bolts go through water jackets). Absolutely no need for that on the LS-based engines, since they go into blind threaded holes. Maybe someone did that to your truck before? If you have a thread chaser, you can try running that through the threads.

 

[2024 White Tahoe]

2008 6.2L Yukon Denali 182K
Replacing factory water pump.
The bolts I removed won't go back in.
They thread ok; I can even start them by hand, get them tight very quickly, and don't want to tighten all the way down.
I don't want to force and strip them.
Even tried without the water pump. Same result, they will start but get very tight just a few turns in. I tried multiple bolts in different holes. Same result.
If I wiggle them a little, I can get them to turn a little more.
But you can still see the "used" part of the thread not going all the way in.
I inspected the threads; they all look ok.
I do notice that the last few threads look shiny.
I am going to clean them up with a wire brush on a Dremel and inspect them better.

I did try to search for this, but didn't find anything.

Also, while I am at it, I am replacing the idler pulley and tension pulley. There were only the top 2 bolts on the tension pulley, but there are 3 holes. Have I lost one?

Any help is appreciated.

Thanks Chris

You may want to post this in the 2007 - 2014 engine Tahoe section. You may get more responses.

 

[ChrisW]

Are your bolts rusted? They'll usually have a bit of rust on the GMT800s I've done in the past, but not horrible. Wire wheel them and that's all I've done. You can always replace them if they are fighting you.

In the past, I didn't know better and added some thermostat sealant on the bolts (like on the SBC, where the water pump bolts go through water jackets). Absolutely no need for that on the LS-based engines, since they go into blind threaded holes. Maybe someone did that to your truck before? If you have a thread chaser, you can try running that through the threads.

They aren't rusted, they are dirty, pretty sure this was the factory water pump and factory bolts, I'm the 2nd owner and the 1st owner kept great records, nothing in them about having a water pump replaced.
Do they use any type of thread locker?
I did inspect them again with high powered magnifying glass, threads look great, no burs or anything, smooth as can be.
Hoping cleaning the up will help

 

[ChrisW]

2008 6.2L Yukon Denali 182K
Replacing factory water pump.
The bolts I removed won't go back in.
They thread ok; I can even start them by hand, get them tight very quickly, and don't want to tighten all the way down.
I don't want to force and strip them.
Even tried without the water pump. Same result, they will start but get very tight just a few turns in. I tried multiple bolts in different holes. Same result.
If I wiggle them a little, I can get them to turn a little more.
But you can still see the "used" part of the thread not going all the way in.
I inspected the threads; they all look ok.
I do notice that the last few threads look shiny.
I am going to clean them up with a wire brush on a Dremel and inspect them better.

I did try to search for this, but didn't find anything.

Also, while I am at it, I am replacing the idler pulley and tension pulley. There were only the top 2 bolts on the tension pulley, but there are 3 holes. Have I lost one?

Any help is appreciated.

Thanks Chris

Figured out the 6.2L engines only used 2 bolts on the tensioner pulley.

 

[strutaeng]

Nothing on the threads AFAIK. Just torque them down in 2 steps. I believe it's 11 ft-lbs then 22 ft-lbs on the second pass.

 

[Fless]

You may want to post this in the 2007 - 2014 engine Tahoe section. You may get more responses.

Thread moved to correct year section. Mods can move threads so please refrain from duplicating. Just ask to have it moved.

 

[Fless]

If you have a thread chaser, you can try running that through the threads.

Ditto on the thread chaser suggestion.

 

[ChrisW]

Thread moved to correct year section.

Sorry about that, wasn't paying attention

 

[Fless]

Sorry about that, wasn't paying attention

No worries; it happens quite often.

 

[solli5pack]

Thread chaser will fix it right up...

 

[Joseph Garcia]

x3 on the thread chaser for the bolt holes. Clean them out.

 

[j91z28d1]

pics of bolts and threads..

as said above. almost always corrosion on the bolts and in the holes on pumps. wire brush the bolts, chase the holes, lube up and bolts and you'll be fine. but pics would confirm

 

[ChrisW]

Ditto on the thread chaser suggestion.

Dont have thread chasers.
Can buy if needed.

I have a very small wire brass brush for Dremel.
The brass shouldn't damage the hole threads.
Do you think that would work?

And of course, I would blow the holes out, may do that anyway.

Should I use tread locker?

 

[ChrisW]

pics of bolts and threads..

as said above. almost always corrosion on the bolts and in the holes on pumps. wire brush the bolts, chase the holes, lube up and bolts and you'll be fine. but pics would confirm

Before cleaning.

Lube with what.?

 

[strutaeng]

Those look fine...

I was going to recommend doing a "poormans thread" chaser using the old bolts. You do this when rebuilding an engine since the head bolts are a one-time use deal: chuck one of the bolts into a vice and use an angle grinder with a thin cut off wheel and score a few lines along the long axis of the bolt threads (3 slices approx. 120 degree apart). Run that through the deep engine block head holes and blow out with WD-40 and clean compressed shop air. It work surprisingly well and have done that several times. You'll almost get some debris and old gunk out of the deep threads.

 

[j91z28d1]

yeah, I'm not seeing the corrosion I was expecting to see. and they won't screw in to the block?

 

[West 1]

Blow out the bolt holes, crud or something is keeping those from threading all the way in. I have used anti seize on many bolts threading into aluminum blocks. Did you compare your new water pump to the old pump to make sure the new pump is not thinner at the bolt holes leaving your bolts too long?