Of course, if the engine were producing a lot of vapors, and you put all the load on cylinders 1 and 2, you might end up with plug fouling, misfires, or possibly cylinder balance issues, because all of the cylinders were not sharing the fumes. Maybe the loose fit at the slot where the J-shaped end fits allows for some gases to flow to cylinders 1 and 2, while the end of the tube dumps so that the other four cylinders can share the rest. So,if it were mine, I would make sure it was right, but probably wait for warmer weather to do it.

OK, went to find a picture (Thanks, Arbelac.) The image below appears to confirm what we suspected. That is, that the loose fit of the tube into the chamber allows some fumes to flow into cylinders 1 and 2, while the end of the tube appears to dump pretty much in the center of the runs for 3,4,5, and 6.

I would argue you should put it together correctly, only based on my experience over the past two weekends. I did my UIM/LIM last weekend and had a hail of a time getting the UIM to sit flat on the LIM. I noticed that no matter how hard I tried the tube seemed to be holding the gasket off from flush with the plenum. After about six tries I thought I had gotten it on. Wrong.

Everything seemed fine till I drove the car. It started making the loudest howling wind type noise from the engine I've ever heard. Took it to a good mechanic I know and he asked me if the gasket sat on properly. When I told him of my difficulty he said that it was prolly that air was getting in (it only made the noise when I let off the throttle). We did a soapy water test, no air on the outside so it was sealed down. So he said it was most likely internal to the UIM.

Took the UIM off this weekend and replaced with the old (which had no problems; I only replaced it to be "safe"). It sat perfectly flat. No noise.

So my experience is that the slightest error can cause problems. I dunno if I could have run it like that for long (I expect not), but why take the chance? The L36/L67s are such good engines, they'll run forver with proper care and maintenance.

Two....I'd venture to think that your noise was an incorrectly seated/sealed PCV. The description you give is a classic PCV o ring missing or out of place. The tube may have held you up from proper install, but the PCV is most likely the noise.

Wow.. It looks like I wasn't the only person to be confused by that j shaped tube!!
The pictures that Agrazela posted really clarify the right and wrong way that tube fits in. Maybe there is a way to get those photos added to some of the other Posts on this topic. It would be nice if Dorman had that clarity in their instructions..even a mention of it would have been nice.

I wish I had seen Archon'* post about trying it through the throttle body opening..I would have given that a try and maybe saved a couple of hours...Although being perfectly honest taking the upper off and on a 2nd time and re-torquing with a more accurate torque wrench gives me a greater sense that I got it right.

Another question on this...I noticed that I seem to have some minor leaking from the
area of the water pump. This is after I flushed the of the Dex-cool and refilled with a Advance Auto'* universal coolant. Is this leaking likely to stop on it'* own (don't laugh please) or should I plan on installing a new pump...The reason I ask is I thought I saw something from GM? recommending using a GM leak stop of some type when ever flushing the radiator.

Again thanks to all !! This site is absolutely the greatest..very impressive group of contributors, thank you so much for taking your time and sharing your knowledge! I know you must have learned it the "hard way" your sharing it with us novices is greatly appreciated!
Spit

Spit...is the leak coming from the pump or the coolant elbow that you recently replaced?

BillBoost

it is definitely not from the elbow. I can see that clearly and it'* fine.

It is hard to see exactly where is it from due to the configuration of the belt & pulleys etc. Where the coolant shows up is directly below the pump on engine casting just above the main engine (crankshaft) pulley. when I wiggle my finger into the back side of the water pump pulley It'* wet and I get clean coolant on my finger....The coolant that I see on the engine casting above the crank pulley is more "oily" probably because it'* seeping down the side of the engine.

It seems like it leaked more 2 days ago after a 140 drive than it did last night after the same drive. (coolant level was the same on each trip) That'* why I was wondering if it could somehow stop altogether on it'* own....wishful thinking on my part I'm sure.

Spit

FIx the leak. Replacing a water pump and/or coolant elbow is a lot easier than replacing a heater core, and a lot less inconvenient than driving all winter with cold feet and a heater that will barely defrost the windshield. I don't like to use any type of stop leak. When your car is brand spankin' new, and all the passages in your engine, radiator, and heater core are factory large, GM could get away with dumping in some stop leak as insurance against coolant seeps. But in older cars (all I ever own) cooling systems are typically crudded up to some degree and adding stop leak can cause coolant blockages where there should be coolant flow or reduce coolant flow to a trickle. For cars running Dex-cool, the places where the stop leak particles accumulate, for example, against the cylinder head coolant passages and LIM sealing surface, the sludge serves the purpose of holding acidic coolant breakdown products against the metal causing pitting and corrosion. IMHO, stop-leaks should only be used in cases of emergency, and flushed as soon as possible thereafter.

I'm glad you figured it out, cuz I couldn't! My guess is that the warp caused something not to seal. PCV valve would explain it.

Just HOPE it ain't from the coolant elbow. (I think) you'll have to tear it all down again if it is coming from the elbow. Bill?

Mine was so corroded that it broke coming out. The jostling is highly likely to have cracked it.

Agreed, it appears that the leak is coming from the lower weep hole of the water pump. Meaning that the bearings are starting to wear.

Removing the tensioner/alternator bracket is the way to replace the elbow w/o pulling the intake again. It'* actually pretty easy to do.