bluehawk2

iTrader: (74)

A friend of mine has a 2005 Z71 with the defective Castech 706 castings. His truck has been loosing water and we pulled the valve covers and confirmed that he has the defective heads.

His engine has 170k miles and we are looking to purchase a 5.3 engine locally.

How can we identify which year and which engines had the Castech 706 heads??

We don't want to purchase an engine that has the same defective heads as the ones he has now.

any help would be appreciated

incbed

If you were able to confirm his heads were Castech then you should be able to do the same agian,,,,also from my understanding it was the Castech 862 heads that were the ones leaking. The shop my friend owns have never had a problem with the 706 heads for them it's always been the 862 heads.

Also keep in mind that your friends heads could have been leaking because of a blown head gasket it does have 170,xxx miles on it.

bluehawk2

iTrader: (74)

I know we can pull the valve covers and rockers and check it, but If I get an engine from the salvage yard I doubt they will want me pulling the valve covers and rockers off of an engine before i buy it.

incbed

If they want your money then they will let you.

If I was your friend and no coolant made it into the oil and the motor still has good oil pressure I would just buy a set a reman heads and just replace his heads,,,I have seen 4.8-5.3's running like new with 30psi oil pressure at idle with over 200,xxx miles on them.

bluehawk2

iTrader: (74)

yeah the oil pan has a lot of sludge in it from the water, but I guess we could clean all of it out and flush the engine really good. I was just wondering if there were certain year models that had the castech heads so that I wouldnt have to go to every junk yard and break 10 8mm sockets trying to get rockers off...lol

incbed

If you just replace the heads I would recommend after replacing the heads to change the oil atleast twice after the engine gets up to full temp to get the most coolant you can out of the engine. I would not drive it or put the engine under any load before changing the oil atleast twice.Then the third time with new oil and filter you should be OK to drive it ,,but then I would change the oil agian after about a hundred miles to make sure all the coolant is gone.If there is still any left after the third change I would change the oil agian after another hundred miles then check to see if there is any signs of coolant in the oil if so repeat the same process until there is no signs of coolant left in the engine oil.

↑↑↑↑The LS engine bearings are really fragile thats why I recommended the Above.

bluehawk2

iTrader: (74)

good advice..............I'm sure the whole engine is full of the milky sludge. We found some older 862(non-castech) heads. Guess I'll be doing a head swap this weekend.