LS3 Based 427 Leaking Sleeve?
Thread Starter
On The Tree
Joined: Oct 2015
Posts: 113
Likes: 45
From: Maryland
LS3 Based 427 Leaking Sleeve? I have an LS3 based 427 with Darton sleeves installed by RED. I just got it running recently for breakin and went to do the second oil change and had a little coolant come out of the oil pan before oil did. It was like 2 ounces or so. This didnt happen during the first oil change. Everything is new on this engine. The heads are 821 casting and were freshly done when installed. I emailed Steve already but its Sunday so itll take him time. Im freaking out because I dont have the money to do ALL OF THIS AGAIN if the block sleeves are compromised. It cost me $3600 the first time. This really disappointing. What options do i really have?
Could just as easily be the head gaskets, porous head casting, or the factory steering cooler (surely you've deleted this already though)
point is its not something to stress out about just yet. If it was my car, Id pickup a handful of coolant test strips, and some of those sealing pellets gm used to put in the aluminum caddys at the factory. Give those a try and the test strips will let you know the progress.
you’ll probably need to change the coolant too.
Steve is quite thorough, I would give him the initial benefit of doubt that it’s something else.
point is its not something to stress out about just yet. If it was my car, Id pickup a handful of coolant test strips, and some of those sealing pellets gm used to put in the aluminum caddys at the factory. Give those a try and the test strips will let you know the progress.
you’ll probably need to change the coolant too.
Steve is quite thorough, I would give him the initial benefit of doubt that it’s something else.
Thread Starter
On The Tree
Joined: Oct 2015
Posts: 113
Likes: 45
From: Maryland
Could just as easily be the head gaskets, porous head casting, or the factory steering cooler (surely you've deleted this already though)
point is its not something to stress out about just yet. If it was my car, Id pickup a handful of coolant test strips, and some of those sealing pellets gm used to put in the aluminum caddys at the factory. Give those a try and the test strips will let you know the progress.
you’ll probably need to change the coolant too.
Steve is quite thorough, I would give him the initial benefit of doubt that it’s something else.
point is its not something to stress out about just yet. If it was my car, Id pickup a handful of coolant test strips, and some of those sealing pellets gm used to put in the aluminum caddys at the factory. Give those a try and the test strips will let you know the progress.
you’ll probably need to change the coolant too.
Steve is quite thorough, I would give him the initial benefit of doubt that it’s something else.
Your in good hands with Steve. There’s no guarantee that a dry-tite sleeved block won’t leak, that’s why Steve asks you to use the GM tablets. Those tablets get dropped into every single new GM engine btw. Steve has sleeved many blocks for me…I have another one here in the shop now in fact, and another in process for another build also. If this does in fact end up being a sleeve issue, Steve will make it right. This is why I only use Steve for my sleeving. There’s a few shops out there that can do it, but you won’t get service from them like you will from RED.
I’m sure Steve already told you, but you want to go back over your head bolts/studs,…back them off a touch and re-torque them one at a time in correct sequence…and let the engine heat cycle a few times afterward.
I’m sure Steve already told you, but you want to go back over your head bolts/studs,…back them off a touch and re-torque them one at a time in correct sequence…and let the engine heat cycle a few times afterward.
Retorque your heads. I would first test to see if anything moved to begin with. I set the wrench to 5 pounds less than tq say 65 pounds and go around and see if something is way off. If something is way off you can try retightening those (or do all like 70 Chevelle says) and see if it works - sometimes it does not and you need to put gaskets in. I just had to do head gaskets. Use ARP lube when installing the nuts (if you have studs) I find much more consistent torque readings with that and less likely a back off of the tq as what may have happened here. Follow procedure that 70 Chevelle said above. You will probably have to undo the headers and you may need to figure out a socket combo to get around the rocker arms since they will be still on engine. Good luck. BTW another test (for another version head gasket problem) is run the car so it gets hot turn off come back 24 hours later. See if you get a hiss in the coolant tank as you open it. If you get a big hiss then combustion air is getting air into the coolant system and pressurizing it. Finally any white sweet smelling smoke when driving or during start up. Not sure what set up you have and how accurate you can read the fill marks on car (I have C6 Corvette and easy to tell if you are loosing water by hash marks). Many times the water in the oil is only a portion of what actually leaked out it can leak into cylinder head and the water can burn up gradually as steam and is vented out or PCVed out.
Last edited by Double06; Nov 25, 2024 at 07:27 AM.
Trending Topics
Get them at any GM dealer. Dirt cheap. BUT-Like lifter trays, if you're gonna go that route, stick with the GM products. Tabs were developed for the Nothstar V8 program many years ago. I used them on a Darton wet sleeved LS1 years ago. They flat work.....
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
I had to put these in my turbo alum 5.3 LS swapped '69 Chevelle. Those should do the trick. Read the directions.
https://www.summitracing.com/parts/NAL-12378255
https://www.summitracing.com/parts/NAL-12378255
Thread Starter
On The Tree
Joined: Oct 2015
Posts: 113
Likes: 45
From: Maryland
Retorque your heads. I would first test to see if anything moved to begin with. I set the wrench to 5 pounds less than tq say 65 pounds and go around and see if something is way off. If something is way off you can try retightening those (or do all like 70 Chevelle says) and see if it works - sometimes it does not and you need to put gaskets in. I just had to do head gaskets. Use ARP lube when installing the nuts (if you have studs) I find much more consistent torque readings with that and less likely a back off of the tq as what may have happened here. Follow procedure that 70 Chevelle said above. You will probably have to undo the headers and you may need to figure out a socket combo to get around the rocker arms since they will be still on engine. Good luck. BTW another test (for another version head gasket problem) is run the car so it gets hot turn off come back 24 hours later. See if you get a hiss in the coolant tank as you open it. If you get a big hiss then combustion air is getting air into the coolant system and pressurizing it. Finally any white sweet smelling smoke when driving or during start up. Not sure what set up you have and how accurate you can read the fill marks on car (I have C6 Corvette and easy to tell if you are loosing water by hash marks). Many times the water in the oil is only a portion of what actually leaked out it can leak into cylinder head and the water can burn up gradually as steam and is vented out or PCVed out.
I am going to retq the heads completely. As far as the coolant in the oil and radiator pressure, i dont have any pressure after it sits. It is loosing coolant, the overflow empited out. Its in a GMT400 truck so not super accurate, but about 2qt of coola t was in there and its gone. There wasnt that much in the oil, so im hoping its just a head gasket issue. I did use the GM tablets as per his instructions. I did notice a coolant smell once when i was driving, so im hoping it was burning it a little. I used cometic gaskets in a effort to not have this issue. Steve said he typically coats them first, even though cometic says not to. Fornnow im doing a retq on the bolts and keeping a close eye on the oil and overflow.
EDIT! I see you used Cometic gaskets. Probably a good idea to retorque. Especially if you've tried the tabs.....
Every leak can have some nuances. Pressure in the system after a day or so would indicate that the cylinder pressure is bleeding into cooling system (another form of a head gasket leak). Your leak may just be pure coolant getting by the gasket and going into a cylinder and or oil pan. Good luck with the retorque but before you do go around see if there were any loose ones that could have been the culprit.
I am going to retq the heads completely. As far as the coolant in the oil and radiator pressure, i dont have any pressure after it sits. It is loosing coolant, the overflow empited out. Its in a GMT400 truck so not super accurate, but about 2qt of coola t was in there and its gone. There wasnt that much in the oil, so im hoping its just a head gasket issue. I did use the GM tablets as per his instructions. I did notice a coolant smell once when i was driving, so im hoping it was burning it a little. I used cometic gaskets in a effort to not have this issue. Steve said he typically coats them first, even though cometic says not to. Fornnow im doing a retq on the bolts and keeping a close eye on the oil and overflow.