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GM's Intake gasket problem

01-29-2006, 07:09 AM
Could someone tell me why all of the intake and head gasket problems are occuring on the 3.1, 3.8 and even some of the 350 truck engines? I have heard of many different causes. Some people claim that 1. The dex cool antifreeze is eating away at the gaskets. 2. Major design flaw in that you don't use two different types of metals joined together. ( Cast iron block with alluminum heads.) 3. Some say it is a design fault with the gaskets themselves. The reason I ask this is because if it is indeed the coolant, well then I can drain the Dex Cool and use the older type of green coolant! Any comments on this subject please.

01-29-2006, 10:45 AM
just a design flaw. Dont use dex cool. Ever. Use the green kind.

01-29-2006, 11:10 AM
There is absolutely nothing wrong with dex cool. tela4422 is right, just a crappy gasket. The replacement part has been fixed. But if you want, yes you can switch to the green stuff. As for your question about cast iron and aluminum. I know the 350s had cast iron heads and blocks, not sure about the 3.1 or 3.8. Could you guys answer that for me?

01-29-2006, 03:08 PM
3.8 has an aluminum lower intake, 3.1 -3.4 is all aluminum. The updated GM gasket kit requires new intake bolts and torquing procedure to do this right, on the 3.1 series engine. No reason not to use Dexcool although it is sensitive to aur getting in the system.

01-29-2006, 06:16 PM
The reason I say dont use dexcool is becuase I ve heard alot of people having problems in their cooling systems when using it. Never heard of a problem with the green stuff. Thats why I dont use it.

01-29-2006, 08:10 PM
If you use DexCool , drain and flush your cooling system more frequently than the original recommendation from GM, (even they now realize that their recommendation of 5 years 150,000 miles was too much, and have stopped putting those stickers in the engine compartment.) When you drain and refill your cooling system, it is also a good idea to replace the radiator cap with a new one as it has been found that some of the caps can become defective and end up leaking air into the cooling system, causing sludging when the air mixes with the coolant.

01-30-2006, 12:27 AM
if you use the green stuff, make ABSOLUTELY SURE its silicate free.

dr olds
02-12-2006, 06:56 AM
yes it is an intake gasket problem but the dexcool does have alot to do with it, after time the dexcool leaves a powdery substance around the rad cap and other areas, this eats the caskets and rubber, also dexcool states it lasts 100,00 miles, it does not, i have friends at and i deal with gm dealers everyday and all of them state that the dexcool is the major culprit for these gaskets failing as soon as they do. they all suggest to get rid of the red and get the green a/f. make sure that you get all the red out before you put in the green because if you mig this will cause an acid and start to eat away at your cooling system. ever since these people have swiched back to the green a/f no problems.

02-13-2006, 08:56 PM
I agree with dr olds, no antifreeze can last 100,000 miles. All antifreeze, even the green stuff that you all think is so good, turns acidic over time. This is what causes problems in cooling systems. My theory is that people think they can go forever without worrying about antifreeze no matter the color and problems occur and they are quick to blame the antifreeze instead of their maintainence schedule.

02-14-2006, 06:43 PM
Fel Pro has the real fix,they updated the intake gaskets.The updated ones are made out of metal instead of plastic.Did a vortec 350 today and put the updated intake gaskets in from Fel Pro(part #MS98000 T for the vortec 350).

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