LQ4 head questions

[Lowcountryfire]

I recently bought a 2002 2500 with an lq4. I have been having a coolant loss issue since i purchased the truck. I am seeing no leaks externally, but im having to add half a gallon or so every few days, and noticed the exhaust steaming for the first few minutes after startup in the morning.. I suspect a blown head gasket.

With that being said, I am very new to the ls platform.. If I am going to be pulling the heads anyways, I have been throwing the idea of doing a head swap around.. My question is, what head would yield the best bang for my buck, without requiring extensive modification? The truck is basically stock, it has a cheap cold air (hot air) intake and some flowmaster mufflers on it.

 

[Tonyrodz]

I recently bought a 2002 2500 with an lq4. I have been having a coolant loss issue since i purchased the truck. I am seeing no leaks externally, but im having to add half a gallon or so every few days, and noticed the exhaust steaming for the first few minutes after startup in the morning.. I suspect a blown head gasket.

With that being said, I am very new to the ls platform.. If I am going to be pulling the heads anyways, I have been throwing the idea of doing a head swap around.. My question is, what head would yield the best bang for my buck, without requiring extensive modification? The truck is basically stock, it has a cheap cold air (hot air) intake and some flowmaster mufflers on it.

You have the 317 heads? How's your oil look? Under your oil cap milky?

 

[Lowcountryfire]

You have the 317 heads? How's your oil look? Under your oil cap milky?

Stock heads, no signs of coolant in the oil at all....

 

[Lowcountryfire]

Just did an oil change last week and the oil looked perfect (dark in color, as to be expected, but no signs of coolant intrusion...)

 

[iamdub]

Just did an oil change last week and the oil looked perfect (dark in color, as to be expected, but no signs of coolant intrusion...)

I'm currently putting my brother's '06 5.3 back together due to a Castech head failure. He saw no evidence of coolant in his oil but it was going somewhere cuz it wasn't leaking externally. The motor was full of sludge when I opened it up. The coolant leak wasn't enough to dilute the oil and make a milkshake, so the water part of it just steamed off and the glycol and whatever else that doesn't evaporate mixed with the oil and has been making sludge for who knows how long.

 

[iamdub]

I recently bought a 2002 2500 with an lq4. I have been having a coolant loss issue since i purchased the truck. I am seeing no leaks externally, but im having to add half a gallon or so every few days, and noticed the exhaust steaming for the first few minutes after startup in the morning.. I suspect a blown head gasket.

With that being said, I am very new to the ls platform.. If I am going to be pulling the heads anyways, I have been throwing the idea of doing a head swap around.. My question is, what head would yield the best bang for my buck, without requiring extensive modification? The truck is basically stock, it has a cheap cold air (hot air) intake and some flowmaster mufflers on it.

Your LQ4 should have the 317 heads, which are a great factory head. They flow as well as the 243/799 but have a larger combustion chamber so the compression is lower. You could have them milled to up the CR, but you can't mill them enough to match the CR of the 243/799 because you'll hurt the flow and kill whatever gains the higher CR would've given. If it were me and I wanted a budget head, I'd get some 243/799s. Personally, I'd shop for the 799 cuz it's a newer casting and it not having "243" stamped on it makes a lot of people not realize it's value. Also, these heads were in everything from Corvettes to service trucks and vans. They're often cheaper coming from a van because people view it as "just a set of heads from a work van".

 

[Lowcountryfire]

Your LQ4 should have the 317 heads, which are a great factory head. They flow as well as the 243/799 but have a larger combustion chamber so the compression is lower. You could have them milled to up the CR, but you can't mill them enough to match the CR of the 243/799 because you'll hurt the flow and kill whatever gains the higher CR would've given. If it were me and I wanted a budget head, I'd get some 243/799s. Personally, I'd shop for the 799 cuz it's a newer casting and it not having "243" stamped on it makes a lot of people not realize it's value. Also, these heads were in everything from Corvettes to service trucks and vans. They're often cheaper coming from a van because people view it as "just a set of heads from a work van".

So the 799 heads would be a direct bolt On? No swapping the pushrods or valve springs etc?

 

[Lowcountryfire]

I'm currently putting my brother's '06 5.3 back together due to a Castech head failure. He saw no evidence of coolant in his oil but it was going somewhere cuz it wasn't leaking externally. The motor was full of sludge when I opened it up. The coolant leak wasn't enough to dilute the oil and make a milkshake, so the water part of it just steamed off and the glycol and whatever else that doesn't evaporate mixed with the oil and has been making sludge for who knows how long.

From the research I have done so far, the 6.0 didn't use castech heads, so I'm hoping that the heads and block are fine, it was just a gasket failure.. But I will know more once I pull the valve covers off..

 

[Tonyrodz]

From the research I have done so far, the 6.0 didn't use castech heads, so I'm hoping that the heads and block are fine, it was just a gasket failure.. But I will know more once I pull the valve covers off..

Let us know what you find.

 

[Lowcountryfire]

I definantly will... I'll probably pull the plugs this weekend to see if I can locate the leaking cylinder, and if I have time pull the VC on that side to see what I'm up against, otherwise the following weekend will possibly be tear down...