Castech Cylinder Heads

03GMC5.3 · November 6, 2011

Lots of oil sludge in that one pic Was that caused by the leak or just not changing oil at recommended intervals?

Our shop has seen a number of Chevy and GMC pickups and vans with a crack around the center head bolt. We don't try to fix the heads at all as it's quicker to get replacement heads and get the vehicle back in service either the same day or overnight. The local Chevy/GMC dealer keeps a supply of replacement heads in stock. And we replace both heads even if just one has the typical crack.

I believe there is a TSB out on this problem. Recommending the sealing tabs sounds like a cop-out. There can also be cracks around the combustion chamber so have a block test done to see if there are combustion gasses in the coolant.

I know we get a good deal from the dealer on a pair of replacement heads so maybe GM is trying to help out with repair costs. It's interesting that we have found the replacement heads we get are Castech's. Hopefully these new castings have fixed the weak point around that one bolt.

when coolant mixes with oil...gets hot and cold....tends to make it sludgy...i hadnt had the truck very long though so who knows if the old owner ever changed the oil...its all clean in there now though and i am right on top of my oil changes...royal purple 5w30 and mobile 1 filter every time...kida funny i just changed my oil yesterday....clean and smooth no chunks or sludge.

03GMC5.3 · November 6, 2011

Lots of oil sludge in that one pic Was that caused by the leak or just not changing oil at recommended intervals?

Our shop has seen a number of Chevy and GMC pickups and vans with a crack around the center head bolt. We don't try to fix the heads at all as it's quicker to get replacement heads and get the vehicle back in service either the same day or overnight. The local Chevy/GMC dealer keeps a supply of replacement heads in stock. And we replace both heads even if just one has the typical crack.

I believe there is a TSB out on this problem. Recommending the sealing tabs sounds like a cop-out. There can also be cracks around the combustion chamber so have a block test done to see if there are combustion gasses in the coolant.

I know we get a good deal from the dealer on a pair of replacement heads so maybe GM is trying to help out with repair costs. It's interesting that we have found the replacement heads we get are Castech's. Hopefully these new castings have fixed the weak point around that one bolt.

I would certainly expect the new heads to be Castech's. I'm sure that GM made them correct the issue and supply them with a number of replacement heads (probably at no cost) or lose their contract plus be sued for non-performance.

I would feel much more comfortable with new heads from Castech then someone taking the defective heads, repairing them and reselling those same defective heads. Don't get me wrong, they may do a great job of repairing the defective heads....... I just wouldn't feel good about it.

i know what your saying about using new heads but the refurb ones were a fraction of the price and they are perfect....my dad has been a machinist for 30 years and i have been a sheetmetal worker/fabricator for 10 years and if i knew that all they do is clean the heads...grind/gouge the casting...weld....then pressure test then we would have fixed my heads instead. but it was nice to have the heads ready to go and very little down time. im just saying that my dad and i are very cautious and anal lol with mechanical stuff and if you can afford new heads by all means go for it...but if you just need your truck to be reliable and back on the road these guys did an awesome job! im pretty sure the company was CHI or cylinder heads incorporated out of texas look em up.

pm26 · November 6, 2011

Nobody answered one of my questions so far: Did GM use other supplier than Castech during that time?

cghbuilder86 · November 6, 2011

I guess nobody knows for sure. I'm thinking they did have other suppliers though.

03GMC5.3 · November 6, 2011

I guess nobody knows for sure. I'm thinking they did have other suppliers though.

yes...to answer your question they did have 2 suppliers...not sure why or what the other one was...but that is why they are not all bad in those years. but im pretty sure all the ones from castech do end up cracking...easy way to tell is remove your valve covers and check the stamp on the head there are plenty of pics of what to look for if you google it you can find the gm bulletin. if you remove a valve cover and there is a mess of sludge and coolant then theres your answer...hope that helped..that is why i started this topic to try and inform and help others from my experience.

pm26 · November 6, 2011

I better check if I have Castech heads on my truck. If I do, I am trading it in. And I am done with GM.

The fact that they did nothing about this issue and expect unsuspecting customers to eat the costs associated with repairs speaks volumes about this company integrity. The least they could do is give 2001-2006 truck and SUV owners a 100k mile power train warranty.

fatalwishes · November 7, 2011

I better check if I have Castech heads on my truck. If I do, I am trading it in. And I am done with GM.
The fact that they did nothing about this issue and expect unsuspecting customers to eat the costs associated with repairs speaks volumes about this company integrity. The least they could do is give 2001-2006 truck and SUV owners a 100k mile power train warranty.

They'll just say that is the old company and they won't warranty the issues. Just like they are doing on the 2008 cars.

This is the new GM.

rkr · November 7, 2011

Does this affect 6 liter engines or is it only 5.3 and 4.8 liters?

rdnkcpa · November 7, 2011

I better check if I have Castech heads on my truck. If I do, I am trading it in. And I am done with GM.
The fact that they did nothing about this issue and expect unsuspecting customers to eat the costs associated with repairs speaks volumes about this company integrity. The least they could do is give 2001-2006 truck and SUV owners a 100k mile power train warranty.

No need to pull the valve covers, and rockers for peace of mind. If you have the Castech heads they will fail near 100K miles. You will start losing coolant with no leaks, puff of white smoke on start up and your lifters will start to clack at start up.

If you do have the problem, repair is about $1,100 for parts doing the work yourself.

I did the work myself, saved a bunch of $$ and the truck is running like a clock.

BTW, GM did nothing for me either, my truck had 119K on it when the heads failed. How many manufacturers warranty something with over 100,000 miles on it besides a mandatory safety recall?

pm26 · November 7, 2011

Isn't pulling the valve cover enough to see the casting mark? Do you need to remove the rockers as well?

DeePa · November 7, 2011

Isn't pulling the valve cover enough to see the casting mark? Do you need to remove the rockers as well?

You need to pull the rockers. The mark is under the rocker rail type thingy...

I too had this issue, happened at 140,000 mi on the clock.

Did not have heat one night, truck ran a little warm on the guage, topped off with water and heat returned.

Next oil change, saw sludge on the dipstick and on the oil drain bolt. Started searching and I had all of the signs.

Slow coolant leak that you could not see, blue/white puff at some startups, lifters making a racket, and sludge.

Pulled the rockers, saw the sign and butterscotch and tar, then ordered new heads from GM and had all of my valvetrain transfered over.

Heads were 600+250 to switch over, and they had the castech marks on the new ones, but they are updated.

Gaskets and lifters were around 450ish

Waterpump/hoses/misc stuff were another 200...

Saved a ton by doing it myself. I did not even try to contact GM as I had 140k on the clock.

Mike

u118224 · December 5, 2011

I changed the oil this weekend on my '04 5.3 Suburban, 140,000 miles. I noticed a little coolant on the bottom on the front diff, traced it up the front of the oil pan on the driver's side. I lost track of it there as my power steering pump leaks a little. I thought it might be coming from the water pump, but there's no evidence of that. I pulled the drive belt and the water pump spins freely with no bearing slop at all. I had to add roughly a quart to the coolant reservoir. I checked the oil before I changed it and it was down a quart or so, which is normal for my engine. I didn't see any evidence of Dexcool in the drained oil, but I wasn't looking that closely either. I guess I'll pull the valve covers tonight and see what they look like. Thanks to all who provided info in this thread.

txab · December 5, 2011

I changed the oil this weekend on my '04 5.3 Suburban, 140,000 miles. I noticed a little coolant on the bottom on the front diff, traced it up the front of the oil pan on the driver's side. I lost track of it there as my power steering pump leaks a little. I thought it might be coming from the water pump, but there's no evidence of that. I pulled the drive belt and the water pump spins freely with no bearing slop at all. I had to add roughly a quart to the coolant reservoir. I checked the oil before I changed it and it was down a quart or so, which is normal for my engine. I didn't see any evidence of Dexcool in the drained oil, but I wasn't looking that closely either. I guess I'll pull the valve covers tonight and see what they look like. Thanks to all who provided info in this thread.

Check the hose clamp connection coming off the throttle body where it attaches to the block. Also look at the crossover tube (metal) from one head to the other for signs of leaking. It can leak around the bolt that holds it down or it can leak at the mating surface. (gasket)

u118224 · December 5, 2011

Thanks txab. I checked everything on top on the engine last night when I pulled the drivebelt. I wonder if it's the water pump gasket. I'll get some cooling system dye and start there.

I changed the oil this weekend on my '04 5.3 Suburban, 140,000 miles. I noticed a little coolant on the bottom on the front diff, traced it up the front of the oil pan on the driver's side. I lost track of it there as my power steering pump leaks a little. I thought it might be coming from the water pump, but there's no evidence of that. I pulled the drive belt and the water pump spins freely with no bearing slop at all. I had to add roughly a quart to the coolant reservoir. I checked the oil before I changed it and it was down a quart or so, which is normal for my engine. I didn't see any evidence of Dexcool in the drained oil, but I wasn't looking that closely either. I guess I'll pull the valve covers tonight and see what they look like. Thanks to all who provided info in this thread.

Check the hose clamp connection coming off the throttle body where it attaches to the block. Also look at the crossover tube (metal) from one head to the other for signs of leaking. It can leak around the bolt that holds it down or it can leak at the mating surface. (gasket)

pm26 · December 5, 2011

I checked on the prices of GM replacement heads for my truck and they are surprisingly cheap - something like $ 320 a piece. Do they come with the valves installed?