Looking for guidance on UIM and LIM removal/gasket replacement.

[billfrank85]

01 3.0 Flex Fuel, automatic, 231k miles, aluminum UIM.

I was in the process of changing out the original PCV valve when the elbow broke off inside of the PCV hose. I cut the end of the hose off, put in the new valve with new elbow, and hooked it up to the hose - the slight shorter distance is pulling the valve out of the grommet ever so slightly, leaving it sit at a slight angle. I can hear the tiniest bit of air coming out of where the valve is seated. Maybe it's an OCD thing, and I'm sure it's not the biggest deal in the world, but I figured the truck is still on the original intake gaskets so maybe I should just dig in a little deeper and replace the lower and upper gaskets and the PCV hose while I'm in there.

I tried searching the forums and YouTube for guides on removing the UIM, some say that the cooling system MUST be drained before doing this. Is this accurate? Is there a guide I am missing on the rest of the steps needed to pull the plenum off?

For the lower intake manifold, I've seen a few guides that say you have to remove valve covers and pushrods to remove the LIM. Is this true? I am just trying to get a scope of what I am getting myself into once I am able to take everything apart. Is there a proper guide for the lower intake with the rest of the process of removal?

Thanks in advance,
Will

 

[stmitch]

Intake Manifold gaskets are rarely a failure point on the Vulcan 3.0, and the deeper you get, the more issues you can create when reinstalling. I probably wouldn't bother with new gaskets if there is no active reason they need replacement.


But if you have your heart set on it...

The 98+ aluminum upper intakes have a small coolant loop that passes through two small ports near the throttle body. Visible here running from heater hoses to intake manifold:

Probably don't need to completely drain the coolant, but you'll need to drain enough for the level to drop below the heater hoses. Many people delete this loop entirely because it serves little purpose. That modification is known as the "Hot Water Bypass" if it's something that you're interested in searching.

Upper intake manifold removal is pretty straight forward. Remove the intake tube, throttle cable, DPFE sensor, and EGR (if equipped). Disconnect electrical connector for IAC. Unbolt the coil pack and set aside (if spark plug wires are removed be sure to note locations). There's also a vacuum elbow at the rear of the UIM that will need to gently be removed. Old, cracked rubber here can cause vacuum leaks.

For the Lower Intake Manifold, coolant will need to be drained as the thermostat sits in the front of the manifold. Fuel rails will need to be unbolted from the LIM. Valve covers need to come off, as the mounting surface for them is about 15% on top of the Lower Intake, while the rest is the top of the cylinder heads.

I have some 3.0 engine tear down and build pics in my build thread here if they're helpful:

Pics of my rig

Looks great! I'm not really big on lowered trucks, unless its a lightning lol. BUT I like it. Love the heat extractor hood. Good luck on the engine work

www.therangerstation.com

I don't recall if the pushrods absolutely have to be removed or not, but it will certainly be much easier to lift the Lower Intake Manifold off if the rocker arms and pushrods are out of the way.