BEDFORDSUBARU Posted July 2, 2015 Share Posted July 2, 2015 Any knowledge you can share on this is greatly appreciated. Putting intake manifold back on my 1997 2.5 after completing head job. When I took the manifold off there was a little piece of white hard caulk on bottom side of what I think is called the idle air control valve (IACV). The caulk was barely still affixed and was falling off. Part of that caulk had been pressed into the small hole on the underside of the valve. I am including 3 picutures of my valve as it is attached to the manifold and you can see that hole. I am also including a picuture of a subaru IACV valve that I just borrowed from an ebay listing. In that ebay picture you can see some type of epoxy around the perimeter of the underside and you can see within that yellow epoxy a spot of the white caulk that must go into that same small hole as it was in mine. So my questions are before I put the intake manifold back on the car: ----do i need to plug that little hole up with some type of caulk or material and any idea what i should use? ---- what is the purpose of that little hole, especially if it is supposed to be plugged with caulk ----if i am supposed to plug up that hole but don't, what effects, if any, will happen? Thanks as always! Greg Link to comment Share on other sites More sharing options...
Dinky26 Posted July 2, 2015 Share Posted July 2, 2015 +1 on this question, I received on of these from a fellow member here, there was this same stuff that just fell off from that exact place/hole. So I am also wondering if this hole needs to be plugged and if so what alternative item/compound can be used? Link to comment Share on other sites More sharing options...
xdeadeye1 Posted July 2, 2015 Share Posted July 2, 2015 lol I just yesterday put my manifold back on my car, I saw this yellow hardened material around the circumference of the thing. It was all hard and falling off.. I paid no attention,, figured it was some factory thing and ignored it.. I didn't notice the hole or the white caulk. Ill be following along here for any answers. the problem I had was I thought I would be smart and replace that small hose that attaches to this "IAC" and attaches to the water manifold on top of the block,, I cut the hose at least 1/2" longer and still had a bear of a time getting it attached,,, it BARELY is on there,,, I may pull it back off and put a splice in it ,, Link to comment Share on other sites More sharing options...
86BRATMAN Posted July 2, 2015 Share Posted July 2, 2015 The hose doesn't go to the block, the large hose off the iacv goes to the intake tube. The large port in the block isffor the pcv system. Link to comment Share on other sites More sharing options...
Fairtax4me Posted July 2, 2015 Share Posted July 2, 2015 The hose doesn't go to the block, the large hose off the iacv goes to the intake tube. The large port in the block isffor the pcv system. Small coolant hose attaches to the coolant crossover pipe. Its kinda tricky to get that hose routed. If you use a generic peice of straight hose you need it to be about 2-3" longer than the original molded piece. 1 Link to comment Share on other sites More sharing options...
BEDFORDSUBARU Posted July 2, 2015 Author Share Posted July 2, 2015 Ok regarding the two sub topics within this post: 1) The small hole on underbelly of the IACV: I am hoping to put the manifold on tonight and if caulking is involved I want to do that very soon so it has some time to dry before I install the manifold. Does anyone know the answers to any of the 3 questions I posed in the original entry? If not, I guess I will go with putting a little white household caulk into and around that small hole and hope for the best. 2) Reattaching that small pain in the rump roast (pita) coolant hose to the IACV: On my 1997 2.5 that hose starts the minor coolant circuit at what I think Fairtax4me is referring to as the crossover tube. The coolant then exits the IACV from a small additional rubber hose which runs up to the throttle body. A third small rubber hose then exits the throttle body and goes to a round metal coolant line that I believe then rejoins the main coolant system right above the thermostat housing. When I did this same head gasket job on this car 8 years ago, even Subaru did not have the part numbers right on the pita hose and that third hose that exists the throttle body. If I recall I actually swapped the the two new hoses and shortened one of them and they matched the original hoses shapes and bends perfectly. I believe I still have the two original subaru plastic envelopes with parts sticker numbers on them if anyone ever need the numbers. Also kept the original hoses I believe. I have found that if the pita hose is oriented correctly as it comes off the crossover tube, and if using the original Subaru shaped hose, that you should be able to slip it onto the IACV nipple without too much problem. Patience is key. Maybe lubing the nipple with a little dielectric grease or equivalent would make it easier. Thanks on any help with 1) and good luck with 2) ! Greg Link to comment Share on other sites More sharing options...
BEDFORDSUBARU Posted July 6, 2015 Author Share Posted July 6, 2015 Just wanted to give feedback regarding caulking the hole. I had a small piece of the original caulk, including the nipple part that protruded into the hole (nipple probably only protrudes around 1-2mm). I applied a little bit of new household caulk to the old caulk,circling the nipple and stuck it back in/on and then but a little more caulk around it to help secure it. Installed the manifold over the weekend and so far the car seems to run and idle perfectly. If anything changes with the idle then I will update here. 1 Link to comment Share on other sites More sharing options...
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