tadchad Posted August 11, 2016 Share Posted August 11, 2016 Has anyone bypassed the heater control valve on a Renix 87 MJ? I saw a couple threads on here about it, but wasn't sure if it is any different in a renix? I don't believe I have any additional lines coming off the main heater hoses that feed the heater control valve. I have a 1987 2.46L, 4 Cyl, TBI : Powertrain 5-speed manual, floor gear shift, 2 W/Dthoughts? thanks. Link to comment Share on other sites More sharing options...
mikekaz1 Posted August 11, 2016 Share Posted August 11, 2016 plug the vacuum line. replace hoses to two straight hoses or put hose menders in. done Link to comment Share on other sites More sharing options...
87MJTIM Posted August 11, 2016 Share Posted August 11, 2016 plug the vacuum line. replace hoses to two straight hoses or put hose menders in. done Correct me if I'm mistaken, but with the Renix, there is the pressure bottle to contend with. Wouldn't you need a T pipe adapter? Straight hoses to the heater core would not work. Does anyone have a part number for a T adapter that replaces the vac fitting? Link to comment Share on other sites More sharing options...
tadchad Posted August 11, 2016 Author Share Posted August 11, 2016 How do I tell if I have a renix or not? I guess I am assuming that since it is a 2.46l 87 it is a renix Link to comment Share on other sites More sharing options...
87MJTIM Posted August 11, 2016 Share Posted August 11, 2016 I don't think the 2.5 is considered a "Renix." But, then again, Renix is associated with the fuel delivery system. If you have a pressure bottle on the passenger side fire wall, then you probably have the heater control vacuum valve. Link to comment Share on other sites More sharing options...
Rockfrog Posted August 11, 2016 Share Posted August 11, 2016 The heater control valve was also used on the HO (open cooling system) vehicles as well. It wasn't just a Renix issue. How to tell if you have a Renix? Well, the TBI 2.5L's used a Renix control system. Heck, the ICM and coil on my buddies 1990 2.5l YJ looks identical to the one in my 88 4.0L MJ. Sent from my SGH-I337M using Tapatalk Link to comment Share on other sites More sharing options...
cruiser54 Posted August 11, 2016 Share Posted August 11, 2016 Just eliminate it with metal splices no matter what. No big deal what it is. Link to comment Share on other sites More sharing options...
tadchad Posted August 11, 2016 Author Share Posted August 11, 2016 Great info , thanks everyone appreciate the help, I just bought it this weekend so I'm excited to get started , it's my first jeep and first mj Link to comment Share on other sites More sharing options...
cruiser54 Posted August 12, 2016 Share Posted August 12, 2016 Great info , thanks everyone appreciate the help, I just bought it this weekend so I'm excited to get started , it's my first jeep and first mj And make sure your heater blend air door is adjusted correctly..... Link to comment Share on other sites More sharing options...
tadchad Posted August 12, 2016 Author Share Posted August 12, 2016 so one more quick question, in the pic coming off my intake manifold in the rear of the engine (red line) goes to my heater control valve, is this the line that I hook directly up to the core, the tube in the front of the engine (in yellow) goes from my water pump to the intake as well, and then the line running left of the condenser (in red) is also going back to the heater valve, so am I correct in saying whatever lines enter the heater control valve are the ones that get directly connected to the heater core? just want to make sure I don't have to reroute that front tube highlighted in yellow. thanks Link to comment Share on other sites More sharing options...
Rockfrog Posted August 12, 2016 Share Posted August 12, 2016 So the one coming from the thermostat housing to the valve goes directly to the core, best to run a new line there. Then you will need a second line from the back of the intake manifold, again directly to the core. The 2.5L used a heated intake as it was still a "wet intake" before it got MPFI in 92. It needed the extra engine heat to help keep fuel atomized. Sent from my SGH-I337M using Tapatalk Link to comment Share on other sites More sharing options...
tadchad Posted August 13, 2016 Author Share Posted August 13, 2016 Cool then I'm tracking ! Appreciate it Link to comment Share on other sites More sharing options...
Rockfrog Posted August 13, 2016 Share Posted August 13, 2016 While you're in there I would consider swapping to the later model water pump outlet (front red hose) it was a formed steel outlet, and eliminated some hose bends (aka chafe points). It may list as a 4.0L part but the 2.5 and 4.0 used the same waterpumps. Sent from my SGH-I337M using Tapatalk Link to comment Share on other sites More sharing options...
tadchad Posted August 15, 2016 Author Share Posted August 15, 2016 Which line goes in the top of heater core and which line goes in the bottom of the heater core????? Link to comment Share on other sites More sharing options...
64 Cheyenne Posted August 17, 2016 Share Posted August 17, 2016 Doesnt really matter with coolant circulating all the time. If you wanted to be mechanically correct then pressure in at the bottom to eliminate any trapped air. On the 4.0 that I have done, went Tstat housing out, to top of heater core in, keeps lines straight and not crossed or twisted. Link to comment Share on other sites More sharing options...
tadchad Posted August 17, 2016 Author Share Posted August 17, 2016 ok, I ended up running the line from the manifold to the bottom (in/supply) and the tstat housing (out/top) just as you, kept it pretty clean. thanks. Link to comment Share on other sites More sharing options...
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