Nas Escobar Posted February 1, 2014 Report Share Posted February 1, 2014 So I did my LIM gaskets to try and fix an idling issue I've had for almost a year now, and I'm almost done but I keep having this weird problem. Everytime that I get the engine put back together, the coolant leaks from under the plenum. It used to spray, but now I can't seem to get it to seal completely where the coolant passage is between the underside of the plenum (not the hose) and the block. My question is, is there a gasket or a seal that I'm missing there, or is there a specific way to put on the plenum? All the holes line up and bolt on correctly, but it seems that depending on how I bolt it near the coolant passage, it will either leak a little bit or spray its guts out. Is there any way to get it to sit correctly, or did my gasket kit miss something where the coolant passage is? All help is appreciated. It's a 94 Cutlass if anyone is wondering what car it is. Quote Link to comment Share on other sites More sharing options...
Schurkey Posted February 2, 2014 Report Share Posted February 2, 2014 I can't remember a connection between plenum and block. Only thing I can think of is the rubber O-ring under the plenum; but I think that seals against the LIM. I know there's an O-ring, I just don't remember it very well. It'll be in the service manual you should buy. Quote Link to comment Share on other sites More sharing options...
Galaxie500XL Posted February 2, 2014 Report Share Posted February 2, 2014 Yes, there's an O ring that sits in a recess in the LIM, and the plenum seals against it. There should have been one included with the new plenum gasket you would have installed, as the O rings don't work well reused. Or, perhaps the O ring came up with the plenum, and now you have two stacked together? Quote Link to comment Share on other sites More sharing options...
Nas Escobar Posted February 3, 2014 Author Report Share Posted February 3, 2014 That I'm not sure of. I know there's an o ring on the block side of things, but not sure on the plenum itself. What size is it? Quote Link to comment Share on other sites More sharing options...
Schurkey Posted February 3, 2014 Report Share Posted February 3, 2014 (edited) That I'm not sure of. I know there's an o ring on the block side of things, but not sure on the plenum itself. I don't remember an O-ring on the block-to-intake manifold. A pair of gaskets, fuel rail, install bolts...Add the LIM-to Plenum gasket and this O-ring, then drop the plenum onto the LIM. Throttle cables, fuel plumbing, EGR and PCV, vacuum hoses, etc. Are you thinking of the oil pump drive o-ring which goes into the block, but UNDER the LIM? What size is it? Not as big as the oil pump drive O-ring. Perhaps 1 1/4" outside diameter (???) Sorry, I don't have photos of the plenum, LIM, or this O-ring. Edited February 3, 2014 by Schurkey Quote Link to comment Share on other sites More sharing options...
Nas Escobar Posted February 3, 2014 Author Report Share Posted February 3, 2014 Are you thinking of the oil pump drive o-ring which goes into the block, but UNDER the LIM? Not as big as the oil pump drive O-ring. Perhaps 1 1/4" outside diameter (???) Sorry, I don't have photos of the plenum, LIM, or this O-ring. That's the thing, I'm not exactly sure what I need or am looking for. My issue is that the coolant leaks out from the driver side corner where the coolant that goes into the plenum goes into the block. Galaxie says that there's an o ring in that passage, but I didn't see it when I took the plenum off, I felt a rubber ring on the block passage where the plenum end meets, but it feels stuck in there. Quote Link to comment Share on other sites More sharing options...
Schurkey Posted February 3, 2014 Report Share Posted February 3, 2014 That's the thing, I'm not exactly sure what I need or am looking for. My issue is that the coolant leaks out from the driver side corner where the coolant that goes into the plenum goes into the block. Galaxie says that there's an o ring in that passage, but I didn't see it when I took the plenum off, I felt a rubber ring on the block passage where the plenum end meets, but it feels stuck in there. Far as I know, there is NO O-RING BETWEEN PLENUM AND BLOCK. At least, I sure don't remember one. The O-ring I'm talking about is between plenum and LIM, and seals the coolant passage that heats the throttle body. Have you bought your service manual yet? Quote Link to comment Share on other sites More sharing options...
Galaxie500XL Posted February 3, 2014 Report Share Posted February 3, 2014 (edited) The O ring is part #6 in this diagram. The O ring sits in a recess in the LIM, the bottom of the plenum where the O ring mates is completely flat. Edited February 3, 2014 by Galaxie500XL Quote Link to comment Share on other sites More sharing options...
Nas Escobar Posted February 9, 2014 Author Report Share Posted February 9, 2014 Would you have the diagram in a bigger size by any chance? Also when I go to place that seal, I don't touch anything on the LIM side, just the plenum right? Quote Link to comment Share on other sites More sharing options...
Schurkey Posted February 9, 2014 Report Share Posted February 9, 2014 Would you have the diagram in a bigger size by any chance? Enlarge it on your computer screen. Hold crtl, press the += key. Firefox has a + button on the toolbar to zoom the page. Or buy the service manual. Also when I go to place that seal, I don't touch anything on the LIM side, just the plenum right? Seems to me you "place" the seal in the groove of the LIM, and the plenum has a matching machined flat surface just parks on top of it. Quote Link to comment Share on other sites More sharing options...
rich_e777 Posted February 9, 2014 Report Share Posted February 9, 2014 I'm looking at the 94 service manual and I only see that O-ring from that image being right underneath the throttle body. If it would help you out I can type the procedure out step by step and sort of guide you through the pics. I am seeing some pins being involved here that appear to go underneath the gasket, any chance you might be missing one of these or that lack of one would cause your troubles? Quote Link to comment Share on other sites More sharing options...
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