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Cracked Heads

black_bird

By black_bird
in Ask A GM Technician

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black_bird New Member

black_bird

Posted
Posted

Hey guys, new to the site and looking for some advice..

 

 

 

2000 Silverado 1500 Z71 5.3

 

 

 

233,000KMS

 

 

 

 

 

I am a victim of the POS "castech" cylinder heads.

 

 

 

First I was adding coolant every month or so, than it was every couple days. No noticeable coolant in the oil. Truck started missing on start-up after sitting for the day (or night).

 

 

 

No visible signs of leaking coolant , ANYWHERE.

 

 

 

Read up and found out the GM TSB for "gradual coolant loss over time with no visible signs of leak", affecting a wide range of 4.8,5.3 engines.

 

 

 

Removed the rocker cover today to find it coated with sludge (caused by antifreze), and a small pool of antifreeze at the rear of engine by valve spring.

 

 

 

 

 

 

 

SOO,

 

 

 

My question is, what should i do about this??

 

 

 

Replace the heads, and if so, with factory REMAN's (non-castech) ($600 each), or is there aftermarket ones?

 

 

 

Replace the motor with a junk-yard gem?

 

 

And while i have the motor torn down that much, should I drop in an aftermarket cam/springs?

 

 

 

 

 

Truck is daily driver, has 230,000KM, everything else stock (minus exhaust and intake).

 

 

 

I dont want to dump a crap load of money just trying to figure out the best route to go....

 

 

 

Im stuck here guys and I have to get this fixed ASAP.

 

 

 

Sorry for the rant, let me know your thoughts/opinions.

 

 

 

Much appreciated.

 

 

 

Thanks,

 

 

 

Neil

MYZ-71 Enthusiast

MYZ-71

Posted
Posted

I`d check prices on aftermarket heads or contact a engine shop and price rebuilt heads, you may also only need one head, I`d check plugs to see if you can determine what cylinder is getting the coolant in it or get a reputable engine shop to check over, 233,000km isn`t alot of km`s for these engines from what I`ve seen, I had a 2000 sierra with a 5.3 that had over 331,000 km`s and still ran like new.

kgrigsby Enthusiast

kgrigsby

Posted
Posted
Hey guys, new to the site and looking for some advice..

 

 

 

2000 Silverado 1500 Z71 5.3

 

 

 

233,000KMS

 

 

 

 

 

I am a victim of the POS "castech" cylinder heads.

 

 

 

First I was adding coolant every month or so, than it was every couple days. No noticeable coolant in the oil. Truck started missing on start-up after sitting for the day (or night).

 

 

 

No visible signs of leaking coolant , ANYWHERE.

 

 

 

Read up and found out the GM TSB for "gradual coolant loss over time with no visible signs of leak", affecting a wide range of 4.8,5.3 engines.

 

 

 

Removed the rocker cover today to find it coated with sludge (caused by antifreze), and a small pool of antifreeze at the rear of engine by valve spring.

 

 

 

 

 

 

 

SOO,

 

 

 

My question is, what should i do about this??

 

 

 

Replace the heads, and if so, with factory REMAN's (non-castech) ($600 each), or is there aftermarket ones?

 

 

 

Replace the motor with a junk-yard gem?

 

 

And while i have the motor torn down that much, should I drop in an aftermarket cam/springs?

 

 

 

 

 

Truck is daily driver, has 230,000KM, everything else stock (minus exhaust and intake).

 

 

 

I dont want to dump a crap load of money just trying to figure out the best route to go....

 

 

 

Im stuck here guys and I have to get this fixed ASAP.

 

 

 

Sorry for the rant, let me know your thoughts/opinions.

 

 

 

Much appreciated.

 

 

 

Thanks,

 

 

 

Neil

This may give you a place to look before you tear down further

 

Last year my 1999 gmc 4.8l 250,000 km had all the issues with the valve noisy lifters, loss of coolant with no visible sign of leaks on outside of engine.

I checked to see if I had the castec heads and did not.

Another thing I found in regards determining if you have antifreeze in you oil is your oil will not always be ' milky' on the oil dipstick to confirm that antifreeze has mixed with the oil, antifreeze does not like to mix with oil. You have to drop your oil and if it comes out kind of chunky or blobs, you have antifreeze in the oil, it will end up on the bottom of your drain pan.

I found the problem when I pulled the intake manifold off, THE TOP ROW OF BOLTS ABOVE PUSHROD GALLERIES, (11mm, not the main head bolts) ON THE LEFT HEAD HAD LOST TORQUE and subseqently antifreeze was able enter the oil pan via the valve pushrod galleries, there was evidence of corrosion, etc on the pushrods, aft lifter area.

At this point I was 90% sure I found the leak but decided to change the head gaskets, when they were pulled I found no evidence of leakage around the head gaskets gaskets.

So what I suggest, pull your intake manifold off, (only way to get at the smaller 11mm? bolts) check torque, if loose retorque, put intake back on (new gasket), if not and no sign of corrosion etc in pushrod galleries continue on with changing out head gaskets. If you do this it should take, 2-3 hrs versus 4-8 hr for a head gasket change depending on your experience.

If you are looking for a complicated explanation for this problem there is not one, that was all it is. Let us know what you find, Good luck and pm me if you

  • 1 year later...
bwlaqua Enthusiast

bwlaqua

Posted
Posted
Hey guys, new to the site and looking for some advice.. 2000 Silverado 1500 Z71 5.3 233,000KMS I am a victim of the POS "castech" cylinder heads. First I was adding coolant every month or so, than it was every couple days. No noticeable coolant in the oil. Truck started missing on start-up after sitting for the day (or night). No visible signs of leaking coolant , ANYWHERE. Read up and found out the GM TSB for "gradual coolant loss over time with no visible signs of leak", affecting a wide range of 4.8,5.3 engines. Removed the rocker cover today to find it coated with sludge (caused by antifreze), and a small pool of antifreeze at the rear of engine by valve spring. SOO, My question is, what should i do about this?? Replace the heads, and if so, with factory REMAN's (non-castech) ($600 each), or is there aftermarket ones? Replace the motor with a junk-yard gem? And while i have the motor torn down that much, should I drop in an aftermarket cam/springs? Truck is daily driver, has 230,000KM, everything else stock (minus exhaust and intake). I dont want to dump a crap load of money just trying to figure out the best route to go.... Im stuck here guys and I have to get this fixed ASAP. Sorry for the rant, let me know your thoughts/opinions. Much appreciated. Thanks, Neil
This may give you a place to look before you tear down further Last year my 1999 gmc 4.8l 250,000 km had all the issues with the valve noisy lifters, loss of coolant with no visible sign of leaks on outside of engine. I checked to see if I had the castec heads and did not. Another thing I found in regards determining if you have antifreeze in you oil is your oil will not always be ' milky' on the oil dipstick to confirm that antifreeze has mixed with the oil, antifreeze does not like to mix with oil. You have to drop your oil and if it comes out kind of chunky or blobs, you have antifreeze in the oil, it will end up on the bottom of your drain pan. I found the problem when I pulled the intake manifold off, THE TOP ROW OF BOLTS ABOVE PUSHROD GALLERIES, (11mm, not the main head bolts) ON THE LEFT HEAD HAD LOST TORQUE and subseqently antifreeze was able enter the oil pan via the valve pushrod galleries, there was evidence of corrosion, etc on the pushrods, aft lifter area. At this point I was 90% sure I found the leak but decided to change the head gaskets, when they were pulled I found no evidence of leakage around the head gaskets gaskets. So what I suggest, pull your intake manifold off, (only way to get at the smaller 11mm? bolts) check torque, if loose retorque, put intake back on (new gasket), if not and no sign of corrosion etc in pushrod galleries continue on with changing out head gaskets. If you do this it should take, 2-3 hrs versus 4-8 hr for a head gasket change depending on your experience. If you are looking for a complicated explanation for this problem there is not one, that was all it is. Let us know what you find, Good luck and pm me if you

 

im having the same problem and done almost everything. ill try this and see what happens.

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