Stabsthedrama

Really need to get the Jeep back on the road like tomorrow, so looking for the best way to properly get all the air out of the cooling system and the coolant circulated through it.

Radiator sprung a leak yesterday, so I swapped it out with a new Spectra ($100 at AZ) and new upper and lower hoses and hose clamps. It was actually an extremely easy process, no need to even take off the front grill, just a few screws and yank off the hoses and drain it into a bucket.

Problem is, I wasn't really thinking and forgot the nature of a closed cooling system. I filled up the bottle and started the jeep - idled fine for a few minutes and puttered and died out. Didn't really overheat or anything, I mean if it did it wasn't too bad and shut itself off - I figure it's because there's no coolant getting circulated, obviously.

So what's the best, easiest way to do this? I have a feeling no matter what it's going to be a bit of a PITA, no?

Also - I have no problem with my stock cap, seems snug as a rug - the tank seems fine too, but perhaps I'll swap that out sooner or later. For now I just need a way to purge it and keep it pretty much stock if possible.

djb383

Let it idle with the bottle cap off AND keep the bottle at least 1/3 full while it's idling/heating up. Keep close tabs on the bottle for several heat/cool cycles. Never let the bottle get empty.

Stabsthedrama

It won't blow out like crazy?

And as it is right now, it's practically full, is that ok? Might just make a bit of a mess at first?

I think it was your post I saw that recommended doing it like this, and I was either going to do this or take the upper hose off the engine, lift it up way high and just start dumping it down into the rad.

Will try your method in a few minutes, thanks.

How do I know when there's no more (or close to it) air left in it?

cruiser54

It shouldn't have puttered out from needing a burp.

Anyway, if you're hell bent on burping it, loosen the temp sender at the back of the head and fill til coolant comes out there. Screw it back down tight, fill the system til the bottle is at the correct level. Put the cap on and start it.

Stabsthedrama

Sweet. Let me go out there and see what happens. I've never had it die out, let me look over everything again.

It did get sprayed pretty good all over the cap/rotor area when it was spraying out into the fan when it sprung the leak and again when I yanked off the top hose, but it wasn't too too bad. I'd think the spark plugs should have stayed relatively dry. I'll open the throttle a bit if I have to...

djb383

The bottle is an expansion chamber......it can't be full to the top, gotta have room for coolant expansion. Like wise, it can't be allowed to get empty, if it does, air is drawn into the system.

Stabsthedrama

Well I had it idling for about 10 minutes, started pushing out the top of the bottle a bit so I stopped for now, will repeat the process in a bit.

Stinks too, ton of coolant got sprayed on the valve cover so it's all burning off.

Seems like if it's pumping coolant through the system, it's doing it rather slowly, but air is constantly coming into the tank on the small return hose at the top, so I guess that's good.

No way to really get the coolant out of the tank at this point, so I'll just keep letting it boil over I guess lol.

Also it tried sputtering a bit again once, I opened the throttle and ever since it's been running totally fine. Not sure what that was about but honestly not too worried about it....yet.

djb383

Got a piece of rubber/vinyl tube (preferably clear)?.....siphon some coolant out of the bottle.

Stabsthedrama

Ya was gonna wait a few minutes and do that. Don't wanna do a scalding hot coolant beer bong. I party hard, but not that hard.

djb383

That's why I suggested clear tubing, so u could tell when coolant was getting close to your kisser......gotta be careful.

Stabsthedrama

Didn't even need to siphon, it sucked it all down or decompressed a bit. Either way it seems fine, I'll idle it a bit more with the cap off one more time later on tonight.

Idle seems fine now, I still think it sputtered cuz it was so confused since the rad was still filling up and all. Seems totally fine now though and the hoses finally started getting nice and hot.

Thanks for the help as always guys.

djb383

Sounds like all is good now.....just be sure to check frequently that the bottle does not get empty when the motor is COLD.

caged

back it up a hill or on ramps and that should get the bottle at the highest point.
another thing i will do is rapidly squeeze the chit out of the upper rad hose to get coolant forced into the rad.

removing the upper hose and pouring coolant into the rad that way helps, as does the temp sensor hole.

djb383

Wouldn't "backing it up a hill or on ramps" make the rear of the motor higher than the front of the motor? Air/coolant exit the front of the motor, so if the back of the motor is higher, it would be harder for air to travel down since it naturally wants to rise. Isn't the bottle just about the highest component under the hood when the vehicle is on level ground? Again, air wants to rise to/stay at the highest point, no?

cruiser54

Well, you combine that with loosening the temp sender at the back of the head.

I've never had an issue with just filling it up and running it....