706 Castech Heads

[Erob]

Hey everyone, so I have an 05 1500 Chevy Silverado, I have heard that the 706 heads generally go out around 140k miles and I’m sitting at 138k.

wanting to get ahead of the break, I’m looking into replacing my heads. Does anyone have any suggestions as to what heads and or brands of heads to put on? Can I get 706 heads that aren’t castech?

 

thanks in advance and sorry if this is a dumb question I just started working on this truck the past couple months.

[CamGTP]

Did you even look to see if you have Castech right now?

 

Yes there are non castech 706/862 heads, GM had a few different cylinder head suppliers. Your other option is a 799 or 243 cylinder head.

[Erob]

46 minutes ago, CamGTP said:

Did you even look to see if you have Castech right now?

 

Yes there are non castech 706/862 heads, GM had a few different cylinder head suppliers. Your other option is a 799 or 243 cylinder head.

No I have not, I'll have to check. But thank you, I wasn't aware they had multiple suppliers, I thought all the 706 heads were by castech.

[Erob]

This is what I found after removing the valve covers. So the heads are cracked correct? Are there any other issues that could cause this?

[CamGTP]

If the oil is milky as well and the coolant temp is dropping, then yeah you have an issue.

 

It's hard to tell if that is a coolant mix or just a real bad oil change maintenance with a bad PCV system on the drivers side head.

[Mr. Z71]

Hey Erob, here's a link for a TSB on the Castech heads showing how to identify them  and where they crack...

 

http://ww2.justanswer.com/uploads/Bluegorilla/2008-12-05_142924_Coolant_loss_5.3.pdf

 

[Black02Silverado]

Also, if you can't do anything right away.  You can add GM's coolant tablets to the system to help seal it. 

 

GM used these tablets in the Corvettes and Cadillac's that had iron blocks and aluminum heads to keep leaks from forming due to the heat and cooling differences in iron and aluminum.

 

I used these in my 2002 Silverado when I changed out the coolant.  Never had any issues with it.  I don't know if I had the Castech heads but I just wanted to be proactive.  All my UOA's came back great. 

 

A friend of mine had the Castech heads and had a leak.  I told him to use these until he could afford to do a head swap.  He had good luck with it and never had a leak afterwards and never did change out the heads.  I guess he was lucky.  He just did a coolant flush to clean out the oil in the system and added the tablets.  He also did several short interval oil changes.

[Erob]

10 minutes ago, Black02Silverado said:

Also, if you can't do anything right away.  You can add GM's coolant tablets to the system to help seal it. 

 

GM used these tablets in the Corvettes and Cadillac's that had iron blocks and aluminum heads to keep leaks from forming due to the heat and cooling differences in iron and aluminum.

 

I used these in my 2002 Silverado when I changed out the coolant.  Never had any issues with it.  I don't know if I had the Castech heads but I just wanted to be proactive.  All my UOA's came back great. 

 

A friend of mine had the Castech heads and had a leak.  I told him to use these until he could afford to do a head swap.  He had good luck with it and never had a leak afterwards and never did change out the heads.  I guess he was lucky.  He just did a coolant flush to clean out the oil in the system and added the tablets.  He also did several short interval oil changes.

Thanks is there anything I need to do with all the goo inside the valve covers other than just clean them out?

[Black02Silverado]

6 minutes ago, Erob said:

Thanks is there anything I need to do with all the goo inside the valve covers other than just clean them out?

Clean them out the best you can and then put them back on.  Then I would flush the coolant and add the tablets.  All of them that come in the pack.  That is what I did.  Then run short interval oil changes.  Get Walmart Supertech oil and filters and run 1,500 mile changes or even less for about four changes.  That is what I would do. Then keep an eye on it to see if it is still leaking.

 

Is the coolant reservoir still clean and orange?  If it is then the leak isn't that bad  yet.