Intake Manifold bypass.

[Vikingone]

On my 85 CJ7 AMC 258 i6 / 4.2l the coolant hoses to the intake manifold are bypassed. As are the hoses to the heater. Living in south Florida no heat really isn’t a big concern. I will be doing the nutter bypass on her soon and am wondering if I should reconnect the connections to at least the intake manifold. If not both the manifold and the heater core. I’m not sure why it was disconnected in the first place so I’m a little nervous. Lol

 

[DaveMueller]

It's there to heat the intake manifold which helps vaporize the fuel. Your call as to whether to leave it bypassed or connect it. Make sure you plug the inlet and outlet if you leave it disconnected (critters and bugs!).

It doesn't have anything to do with the Nutter bypass (I think), it's a standalone system. If the ECM is still running the engine, it will be screwed up because there are temperature sensors in the intake manifold and they'll never be at the proper temperature with no coolant flow. There's also a vacuum switch that operates the EGR, vapor canister and a few others; same problem here if it never gets to operating temperature.

Even if you bypass the heater core, connecting the manifold costs you a few bucks for hose and should make the engine run better. What do you have to lose?

 

[Vikingone]

Thanks!!!!!