Coolant Leak Between Head and Block

[EightTrackHits]

I recently bought a well kept 2005 Silverado with a 5.3 and 187000 miles on it.

All of the maintenance records were present.

I have a coolant leak that I've been having a hard time nailing down.  It has leaked from a couple of different spots.

The first was at the y pipe on the passengers side.  This was before I had it and was replaced.  But it did leak from hose clamps some since I've had it.

The second was a coolant smell that I did not know where it was coming from.  The leak got worse over time and coolant was visible under the truck.

I put it on stands and did an inspection, the picture is the area on the drivers side between the head and block.  I have 706 heads, but do not know if they are castech.

My plan it to pull the heads and check to see if they are castech, inspect the cylinder walls, have a machine shop inspect/repair the heads, look for evidence of coolant in the oil (perhaps send off a sample).  If everything is repairable and there is no evidence of coolant in the oil, I will replace head gaskets (both), reinstall the heads, and go from there.  I'm not convinced that this is the only coolant leak.  I recently took a 300 mile trip towing a trailer and my temp gauge was reading slightly low.  

If anyone has replaced head gaskets without pulling the engine or if anyone has anything to add, please chime in.  This will take me a while as I am slow with this sort of thing, but I will follow up with the posts until I'm done one way or the other.

 

Thanks!

[CamGTP]

Removing the heads with the engine still in the truck is very straight forward. Remove everything on top of them and remove the exhaust manifolds. The heads will come right off that way.

[richard wysong]

possibly the intake manifold too. you will find out as you pull it apart to do the heads

[txab]

2 hours ago, richard wysong said:

possibly the intake manifold too. you will find out as you pull it apart to do the heads

Negative. Dry intake on his 5.3.

 

There are crossover tubes, from one side of the block to the other, both front and back. They are located just slight away from the intake. They have gaskets that can leak. I could see where if the rear leaked it would run around the valve cover and leave a trail similar to OP's.

 

Once you pull the intake you should be able to tell. Also you might put a dye in the coolant and see where the leak begins

Edited October 30, 2021 by txab

[EightTrackHits]

Thanks Guys,

 

I worked for about 45 minutes on it tonight and got as far as the alternator bracket.  Mine looks to be one continuous piece that also has fasteners behind the power steering pump pully.  Not much progress but it is in the garage and the job is started.  So, off to borrow a pulley puller tomorrow.

I'll keep an eye out for a leak on the on the rear crossover tube as I move forward.  Below is the video I'm using as a guide.

https://www.youtube.com/watch?v=2U3JlOU5ER4

Thanks again

 

Edited November 1, 2021 by EightTrackHits
update

[txab]

@12:50 is what I was talking about having a gasket than can leak at times

[EightTrackHits]

Thanks!  I'm going to look that area over good with an inspection mirror once I have the intake off.

 

On another note, I went back outside and was able to remove the alternator bracket without removing the power steering pully.  Will be back at it tomorrow after work.

 

[Sharpz]

glad to see you are using a video to guide you through this process.  I was going to suggest it since there are about 10,000 of them made for these vehicles.  A good practice in the tear down portion when you do it in multiple days/breaks is to spray the bolts for your next step, and all those you can find after with PB blaster, some multiple times such as the exhaust manifold bolts. 

[EightTrackHits]

Got the intake and left exhaust manifold off at the heads.  Pretty dirty under the intake.  Left exhaust clamp is pretty tight.  Only one fastener came off, but I think I can get the head off without having the manifold all the way off.  Considering re-torquing the head and doing a compression check. Thoughts?  May not have an update tomorrow as I have a meeting after work.

[EightTrackHits]

The carbon in my intake looks excessive to me.

[EightTrackHits]

Results of the compression check are 1 160, 2 165, 165, 4 165, 5 175, 6 160, 7 175, 8 160.  No gross differences on a cold compression check.  Left side rockers are darker than the right, but I read that this is not necessarily a bad indication.  Below is the right side.  I’ll attach the left in a different post.

Edited November 2, 2021 by EightTrackHits
ETA pick of left side is to exceeds size limit for one reason or another. Rockers are slightly darker, but very consistent. Heads are coming off tonight.

[EightTrackHits]

Heads are off.  They are the 706 Castech heads, but no evidence of the crack described in the TSB.  Below is a pic of the cylinder near the leak; it is the cleanest one.  There was no sludge in the heads or elsewhere, so I think I caught this early.  I’m considering getting a different set of heads due to the TSB, but I may have these inspected and may keep them.  Do any of you know of an instance where the castech heads were deemed good and retained?

[shakenfake]

No get a different set. There was a way to repair them but I don't know much about it.

[txab]

Did you have any broken exhaust manifold bolts or break any taking them off?

[EightTrackHits]

16 hours ago, txab said:

Did you have any broken exhaust manifold bolts or break any taking them off?

I rounded off a nut on a flange, afterwards I soaked it in PB blaster and borrowed a Snapon 6 point impact socket.  The nut was so deformed that I had to lightly hammer the socket on, but it took it off and the other five were no problem.  No problem with the exhaust manifold bolts going into the heads.  If one of them were to break, I would likely try to remove the manifold and weld a nut onto what’s left of the fastener going into the head on the bench.  That’s worked pretty well for removing broke fasteners before.
 

There are a couple things I’d do differently,  I took my exhaust manifolds all the way off,  I will just move them out of the way next time as coolant got into the exhaust when I pulled the head.  Also I will drain the block more completely next time, I understand there is a plug.

Edited November 3, 2021 by EightTrackHits
Happy birthday txab!