Replacing lower intake manifold gasket - coolant drain required? [Archive] - DodgeIntrepid.Net Forums - Dodge Intrepid, Concorde, 300m and Eagle Vision chat

: Replacing lower intake manifold gasket - coolant drain required?

11-25-2009, 11:21 AM
Hi all,

My car has been having some erratic idle speed (like it is bouncing around). I suspect the IAC is sticking a little and there's too much oil puddle in the plenum and the IAT is dirty. So I'm gonna take the plenum off and clean things up a little. But since i've had non-smooth idle before I really start noticing this, I also suspect maybe the lower intake manifold gasket is not in the greatest shape. The question is do I need to drain the coolant or disconnect the fuel line if I just wanna replace the gasket? I can't visualize what's happening underneath there. I don't want to do either the drain or the fuel line.

Thanks for the help,


11-25-2009, 11:49 AM
you will have to drain the coolant, disconect the fuel line I don't think so.

11-25-2009, 11:54 AM
You'll have to remove the fuel rail to remove the lower intake but you don't need to disconnect it from the fuel line. Since you're only replacing the gaskets you might be able to do it with out disconnecting the cooling system. Disconnect the harness plugins from the coils, injectors and a few other things, remove the plenum, remove the fuel rail and injectors from the heads and lower intake. Unbolt the lower manifold, lift it and you should be able to move it side to side so you can remove and install the two new lower intake gaskets.

11-25-2009, 12:38 PM
sweet. Thanks for the help!

11-26-2009, 01:05 AM
I ended up cleaning things and only replaced the plenum gasket. There's no way to do the lower without draining coolant (at least 1/4 to 1/3). Fuel is indeed not needed, just moved aside. Idle seems better now, so I'll worry about the LIM gasket later.

11-26-2009, 01:59 AM
I was able to do it before but come to think of it the hoses aren't OEM and might be a tad bit longer on mine.

11-26-2009, 02:12 AM
yeah you can do it without draining the coolant... you're just going to end up having a huge mess is all.

11-26-2009, 01:30 PM
You'll drain the coolant either way, either thru the petcock/lower hose, or into the valley between the heads, and have a mess. There are 4 coolant passages that are opened when the LIM is removed. Fuel rail has to come off as well, I prefer to completely remove it and get it out of the way, only takes a second to unclip it from the fuel line after all the bolts are out.

11-26-2009, 01:42 PM
That's exactly what I figured after looking at the thing. I'll just deal with it later if it needs to be done.