Water pump? Coolant?

[muddeprived]

My heater is doing nothing unless i'm on the gas. Usually i warm up the jeep for 10 min and my aftermarket heater gets everything scorching hot inside but now it doesn't do anything but blow cold air unless i get in and start driving then it blows hot. It seems as if the hot coolant is not cycling to the heater unless I'm applying power to the motor. Engine temps reach normal temps (210ish) within about 7 minutes. Does this sound like the pump goin bad or am I running out of coolant (havent checked since it's too dark to see)?



Thanks

[joe_and_jeep]

Check yer coolant, its rare that a water pump goes bad to where it starts to not move fluid. They usually leak first.

[Mykal]

Agreed.
Is your radiator cap hot after the motor is up to temp?
I'm going with rad cap and thermostat after low coolant or air in the lines.

[joshs1ofakindxj]

Could this be a vacuum issue?

You could have a vacuum actuated blend door in the HVAC system that isn't moving to let hot air to the cab.

[muddeprived]

I don't use the stock heater. My aftermarket heater is hooked up to the pump instead of the heater core. I haven't touched the stock heater/AC since i bought it.

I just recently had my cat #2 replaced and maybe they had to remove the coolant lines to make room. I'll check on the coolant level.

How do you get air out of the system? Burping? How's that done?

[Mykal]

Open the radiator. Fill the radiator and reservoir to proper levels.
Start the vehicle. Let it come to normal temperature with the radiator cap off.
Watch for bubbles in radiator spout. As air escapes the coolant level will drop. Refill the radiator as needed.
Squeeze the upper hose gently to help move the air out. Once it stops burping air out, cap it.
Check your reservoir the next couple of times you drive it and refill as needed.

[DixieJeeper]

Also be careful to inspect how you ran your heater hoses to the mojave/aftermarket heater. The hoses always need to be lower than the radiator cap. So if you have a big "S" or "U" bend in the hose it needs to be lower than the valve cover otherwise you will create an airpocket in the hose no matter how many times you burp the system.

[muddeprived]

I checked the fluid today and it was low as shi$. Took 3/4 of a bottle to fill it and the reservoir. Burped it a bit and kept it full till operating temps hit 210 then I tried the heater. Nothing but cold air. Lightly pressed the accelerator and it got warm instantly.

What I noticed was one hose coming into the heater was warm but the other hose was cold. When I hit the accelerator, the other became warm. Does this mean anything? Sounds like nothing is pushing the coolant through the heater.

[muddeprived]

Also be careful to inspect how you ran your heater hoses to the mojave/aftermarket heater. The hoses always need to be lower than the radiator cap. So if you have a big "S" or "U" bend in the hose it needs to be lower than the valve cover otherwise you will create an airpocket in the hose no matter how many times you burp the system.

I do have part of the hose a little higher than the cap. It goes straight back from the pump above all the engine crap then around the backside of the valve cover then down alongside the frame rail, to the left of the cats. If air was in there, wouldn't it have been causing me issues since day one instead of just showing up out of the blue a few years later?

I am thinking of redoing the hoses so it's a more professional lookin job than how I have it now. At that time I was in a hurry to get heat because my heater was making me sick as hell so I rigged up the heater in one night and left it that way since. It's not BAD but it ain't pretty.

[muddeprived]

Tried again this evening and same deal, no heat upon warmup until I start going. Should I focus on air pockets or the pump? Or just go buy a JK?

[chux72vette]

Sent you a PM

[Mykal]

Is your radiator cap hot after the motor is up to temp?

Also, with the cap off and motor at operating temperature can you see any flow in the radiator funnel?
With the cap on the radiator and motor at operating temperature if you squeeze the upper radiator hose and let go do you feel the coolant being pumped through the hose?
Flushed the system?

Then change the water pump.

[muddeprived]

Also, with the cap off and motor at operating temperature can you see any flow in the radiator funnel?
With the cap on the radiator and motor at operating temperature if you squeeze the upper radiator hose and let go do you feel the coolant being pumped through the hose?
Flushed the system?

Then change the water pump.

I just checked the cap and it feels slightly warm, not hot at all. Yeah I saw the fluid moving a little bit with the cap off. I can't tell if there's fluid running through the hose because all I can feel is the fan and motor running. I haven't had the system flushed. I bought the jeep in 08 and it recently had a new radiator put in due to a crash I assume and the fluids were clean and fresh so I haven't bothered with a system flush.

What options do I have regarding a new pump? I don't want remans or used crap from the yards. I'm looking at B-S-N pumps, or maybe upgrade if it ain't too costly.

[Mykal]

Im still betting on thermostat and cap.

I've always used oem or reman waterpumps no issues with them so I don't know about your options.

Do all three since you will be in there. Sounds like you are convinced it's the water pump.

[muddeprived]

Im still betting on thermostat and cap.

I've always used oem or reman waterpumps no issues with them so I don't know about your options.

Do all three since you will be in there. Sounds like you are convinced it's the water pump.

yeah i'm gonna hit it all at once and be done with it.

[joe_and_jeep]

The thing that strikes me as odd is that you been running this setup for a little while. I don't think its the routing of the hoses or anything like that. I've seen the impellers on waterpumps (rare) go bad and I've see thermostats partially open. I would park the Jeep on an angle so the rad cap is higher than everything else. Put the LF (I think that is the side the cap is on) tire on a ramp or a curb or something. Burp it that way, if that doesn't get all the air out then I'd do the water pump. I'd do the cap and thermostat first, its good preventative maintaince anyway.

[muddeprived]

The thing that strikes me as odd is that you been running this setup for a little while. I don't think its the routing of the hoses or anything like that. I've seen the impellers on waterpumps (rare) go bad and I've see thermostats partially open. I would park the Jeep on an angle so the rad cap is higher than everything else. Put the LF (I think that is the side the cap is on) tire on a ramp or a curb or something. Burp it that way, if that doesn't get all the air out then I'd do the water pump. I'd do the cap and thermostat first, its good preventative maintaince anyway.

Will do. Thanks Joe.

I can't recall what temp the stock thermostat is? Should I keep the stock temp or go a little lower maybe?

[Mykal]

195
Keep stock temp.
13 - 18 lb radiator cap

[muddeprived]

Awesome, thanks! I'll tackle this stuff on my day off from work.

[cityslicker]

Maybe yinz can help out my buddy, his xj 86 I think is overheating. He said he replaced the Thermo and waterpump. and still overheating. Sorry for the jack but its kindo on the subject.
I didn't know what to tell him, he said overheat I thought of the thermo and waterpump. unless he got broke shit from the gate. or hooked something up wrong.

[chux72vette]

Maybe yinz can help out my buddy, his xj 86 I think is overheating. He said he replaced the Thermo and waterpump. and still overheating. Sorry for the jack but its kindo on the subject.
I didn't know what to tell him, he said overheat I thought of the thermo and waterpump. unless he got broke shit from the gate. or hooked something up wrong.
MIke, there has to be something causing it besides those things then. Like a blown head gasket can as well as timing off,,,all sorts of things. Anybody would either need more info or hands on. Wheres he at as if close enough I could maybe take a look but anyone else can chime in too. EDIT* Have him check his oil and see if a milkshake as could be an indicator but not all the time on a HG as it can be blown between cylinders. Tell him also to see if there are bubbles in the external watertank too.

[ridgerunner97]

86 is a Renix they had that different cooling system, I can't remember the special issue with them but there is something else to check, do a quick google search...

[cityslicker]

He said he searched and found many threads with the same issue, He thinks its an air pocket reducing the amount of fluid in there. said something about having to jack up the ass-end, or parking nose down on a steep hill. and burping it.
I will tell him to check the oil though. see if its frothy I guess, you mean like coolent getting through the head?

[DixieJeeper]

Renix (closed pressure vessel cooling sys) are notorious for cool sys problems- and mainly air pockets and bad caps- aside from the ordinary cooling sys. problems. search on here I wrote up a pretty detailed cooling system fault tracing for somone recently.