Posted: Sat May 26, 2012 4:37 pm Post subject: Intake gasket change on 3.4 Impalas
Ive done the lim gaskets numerous times on my car and friends cars with 3.8 (L67's)..and its a breeze. I have a friend with a 3.4 and he says his gaskets are going and leaking coolant from the rear of his engine. How much harder are the intake gaskets to change on the 3.4's from the 3.8's? How much different are the gaskets also? Thanks.
The gaskets themselves are completely different because the intake manifold is completely different on the two engines. As far as the replacement goes, I believe it is a bit more complicated than the L36/L67 because the rocker arms/pushrods need to be removed to do the gaskets on the 3400. I've never done one, but I'd imagine if you can handle a LIM gasket on the 3800, you can probably do a 3400 with little trouble.
Protip: If you don't know what you're doing, don't do it.
[quote="IffyG"]The gaskets themselves are completely different because the intake manifold is completely different on the two engines. As far as the replacement goes, I believe it is a bit more complicated than the L36/L67 because the rocker arms/pushrods need to be removed to do the gaskets on the 3400. I've never done one, but I'd imagine if you can handle a LIM gasket on the 3800, you can probably do a 3400 with little trouble.[/quote]
That pretty much sums it up... next to removing brackets here an there.. tell him to change both head gaskets while he's down there
You do have to take the rockler arms off to remove the push rods.
Keep the push rods in order. Mixing up an intake rod with an Exhaust rod will result in a bent Intake value and push rod when you crank it over the first time after assembly.
Have a manual with complete torque specs handy.
Have a really good INCH pound torque wrench.
and do not exceed teh specs for the Rocker arm retorque or you will pull the threads out of the Head.
It take about hour or 2 longer than a 3.8.
The LIM end gaskets are made from the supplied RTV in th egasket set.
Most places list 2 gasket sets get the expensive one, it has the new Metal backed gaskets.
60deg V6 intake gasket change is a huge pain in the ass. It pays next to nothing and every car that ever had a 60deg engine installed is owned by a cheap prick.
Here's how you do it:
Take off the overflow and set it aside. Remove the engine struts, ACC drive belt, ALT, PS pump, and all the vacuum, computer, injection and ignition equipment on top of the engine. Remove valve covers, UI, LI, rockers, pushrods. Clean gasket surfaces, replace everything.
When you order the gasket kit (Dorman 615-205), don't forget to get injector O-rings. (O-ring kit: AC-Delco 217-1427) They're not in the kits because the kits are made by idiots. Don't mess up the injector connectors or the pushrod locations. Intake pushrods are shorter than exhaust pushrods, in case you screw it up.
Torque the center bolts in the lower intake first. Those and the valve covers are torqued to 10ft-lbs, the rest of the intake bolts 18ft-lbs, the rockers 30deg past 25ft-lbs. If you get the Dorman kit, it comes with bolts for the lower intake. It also comes with a lot of stuff you don't need, because it covers multiple applications.
Change the oil at least twice after you do the job, or until it comes out free of coolant, then change the filter. If you're selling the job, sell plugs and wires too, and a thermostat and gasket, and a coolant flush, new air filter and top end/throttle body/fuel injector cleaning service. Clean out the overflow tank while you have everything apart so it looks like you did something.
Thanks again guys. So i tackled the job and it took me all day starting at 8 am and engine at 9 pm. I then put everything back together and the car then starts getting a fuel leak from the Fuel Rail Inlet. Is there supposed to be a gasket or something for them? The leak comes from the behind after the thread bolt.
Probably wouldn't have leaked if you used the quick disconnects like four inches away and left the rail alone. There's an O-ring on the fuel inlet and on the FPR. I don't remember if the inlet O-ring goes on the coupler or inside the rail. The O-ring kit number I have above doesn't include those O-rings.
Yea so i went to the junkyard and got the oring from 2 other 3400 and 3100 just in case so everything went good and i finally finished the crappy damn 3400 impala. Ill stick to my 3800. NEVER AGAIN!!!!
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