On my 2004 4.0l I took off the hose that comes from the heater core to the water pump to burp that air out. Ideally don’t take it all the way off but where it ties to the hardline you can usually fit a jewelers screwdriver in there to create an outlet for the air. Also if all else fails I have taken both heater core lines off and sprayed into it with a hose.


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The spill free funnel works great.

 

disconnect the outlet hose at the firewall, and crank it up. you'll get the air out, or it's time to force it out, with a hose. shut it off, and disconnect the other hose too. get a garden hose repair kit, female end. it should have a nipple with barbs on it. screw it to your garden hose, and stick the barb into either hose and hold it. have someone else crack the water on, and watch to see the air come out. watch the water too. if it comes out filthy, run it until it clears, then swap the garden hose to the other heater hose, and blow it out again. swap back and forth until it flows clear from both sides. hook the lines back up, and run it again to burp it. you should have heat now. if not, do what i did, and move someplace warm. >

 

And don't use a water hose with the water valve all the way open. The system is only designed for <16 psi. Water pressure can be upwards of 100 psi.

 

what he said. i said "crack" meaning just get the water flowing. besides blasting water all over you, and everything under the hood, too much pressure will give you a new set of problems, you don't want to deal with. a water stream you would feel comfortable with pointing directly at your face to drink from, is what you seek. don't be a stanley spadowski!

 

Which is the outlet hose, the top one or the bottom one..?

 

Thanks Guys, did Golden Arms suggestion, flushed out the core from both directions, re connected the bottom hose and filled it up with coolant then reconnected the top hose, it seemed to be warming up, so topped up coolant and went for a drive (it takes forever to warm up at idle), first down hill road it started to blow cold again. I CANNOT shift this air lock from my heater core, it is turning into a real enigma, any ideas..?

 

I am not familiar with this diesel at all, maybe some pics would help us over here get our head around the plumbing you have under the hood.

My 4.7L has a bleed port you HAVE to remove to bleed the air out. Back in the day, I used to remove the heater hose that attached to the thermostat housing on the front of the 4.0L to fill it with engine off. I would fill the hose until coolant backed out, then fill the port at the thermostat housing where it attached until it was full, then reattach the hose and run engine. It still sometimes needed a cool down period after this procedure, where i would wait until it was completely cool, then top off the radiator up to the radiator cap neck. After all this, I rarely had a 4.0l that i couldnt get the air out of.(this used to be a real pain in the backside). My point here is...You have to find a way around the thermostat to purge air out of the system while cold.(the port on the thermostat housing on the 4.0L bypassed the thermostat and directly filled the head and block through a small opening), and the best way to get all the air out, is by using the highest opening on the engine you can find. Sometimes the radiator cap is highest, sometimes not. This is the reason Jeep puts a bleed port on the V8's, the radiator cap is not the highest point in the system. Physically look over the engine bay, and find the highest point in the system, and see if you can remove a hose or something similar, and fill the system there. When you do, fill the hose or port until it is full, walk away for a few minutes, then come back. If the coolant has dropped, fill again, and repeat until the coolant level stops dropping. (might take several hours) When you get to a place where you are certain it is full, reattach all connections, and begin again filling at the radiator cap. Same process, fill till full, walk away, come back and fill again, walk away, etc...Then when you get the radiator to stay full, try again starting the engine and fully warming it to operating temp. run the Jeep around a little bit, then come back and shut it down and cool it completely. If the coolant level remains right under the radiator cap when you check it when cold, then you are full. If it is low again, you had air in it, and you need to start over refilling and walking away....It can be a pain i know, but until you get the coolant to stay full right up to the radiator cap when cold, you arent getting all the air out, and can have an airlock that slows or stops your ability to keep the engine cool. (by the way, ignore the overflow bottle throughout this process, because it wont work properly UNTIL you get the system full. Always add coolant at the radiator cap or open port/hose on engine)

Now...that being said, I wonder about your thermostat condition. which will frustrate this process terribly. If your thermostat is stuck shut, it will make it darn near impossible to get all the air out. You mentioned it takes longer than it should to warm up the engine. This be be caused solely by the airlock, but it could be a sign of a failed thermostat as well. Might want to swap it for a new one, if the above procedure doesnt help....

 

Succes, at last

Thanks Bigrigr. I did some of what you said, I filled the matrix (core) from tho pipe into then without running the disconnected to thin return pipe from the top of the cylinder head (highest point) and via a funnel and small tube slowly poured coolant into it until bubbles stopped coming out. Started the car and allowed it to warm up, then hey presto the heater blew hot..... only on the passenger side. Having changed my blend doors last year I had easy access to them son moved them manually, and it blew hot out of all vents, I suspect the motor/actuator on the right hand side, drivers side (it is a UK car) is not working properly, so will mod it to work from just one motor. Thanks for your help man, really appreciated, all of you.

 

Thanks Bigrigr. I did some of what you said, I filled the matrix (core) from tho pipe into then without running the disconnected to thin return pipe from the top of the cylinder head (highest point) and via a funnel and small tube slowly poured coolant into it until bubbles stopped coming out. Started the car and allowed it to warm up, then hey presto the heater blew hot..... only on the passenger side. Having changed my blend doors last year I had easy access to them son moved them manually, and it blew hot out of all vents, I suspect the motor/actuator on the right hand side, drivers side (it is a UK car) is not working properly, so will mod it to work from just one motor. Thanks for your help man, really appreciated, all of you.

Glad that worked. Just epoxy your blend doors together and eliminate the other actuator. Thats what i did....Just make sure you break out the little tab in the drivers side door(RH drive) so it can spin freely while the actuator stays still. Then the passenger side actuator will control them both...

 

glad he got it sorted, i will say this though, if you do replace a thermostat, drill a hole in the flat face of it. a 1/8" hole will allow all of the air to bubble through, without affecting the operation of it. some thermostats have some cheesy little hole, with a little piece of metal like a flapper in it. just get a regular thermostat and drill the hole. it will save you a lot of time bleeding air, as you won't have to wait for the thermostat to open, to purge air from the bottom end.