New radiator & thermostat installed but not sucking coolant

[ComancheNewbie]

I'm about ready to blow this truck up! I just installed a new radiator and thermostat and the engine isn't sucking in any coolant. I ran it way above "normal operating temperature" and still nothing. WHAT'S WRONG!?!?

[87Warrior]

Did you get the belt routed correctly? Pump could be spinning backwards.

 

Also, did you get the right pump? Some of the early Jeep pumps are a 'reverse flow' set up.

[Wildman]

:agree:

 

Also........did you get all the air out of the system????

 

There are several write ups about how to burp the cooling system around here.

 

With NO air in the closed cooling system, you should have filled it with appox 2+ gallons of coolant, as a good measure that the air is out of the system.

[ComancheNewbie]

Did you get the belt routed correctly? Pump could be spinning backwards.

 

Also, did you get the right pump? Some of the early Jeep pumps are a 'reverse flow' set up.

 

I didn't replace the water pump. Just the radiator and thermostat.

[ComancheNewbie]

:agree:

 

Also........did you get all the air out of the system????

 

There are several write ups about how to burp the cooling system around here.

 

With NO air in the closed cooling system, you should have filled it with appox 2+ gallons of coolant, as a good measure that the air is out of the system.

 

I guess their could be air in the system, I know this is common.

[1987Comanche]

The HO T-stat housing has a sensor that makes an excellent bleeder screw and is a direct bolt on for Renix trucks. I did this when I changed the T-stat and never had to pull the coolant temp sender out of the head. If another T-stat housing isn't an option then pull the sending unit from the head but be careful...they can snap off sometimes.

[LarryH88bt]

I did my radiator recently, all I did to bleed out the air was fill it at the bottle and squeeze the upper radiator hose to burp it. Eventually it stopped blowing bubbles and the coolant stayed put. Then run it for a while and repeat once the engine is cold.

[ComancheNewbie]

I guess I just had air in the system, because it finally started circulate coolant. Now on to the next problem! :shake:

[ComancheNewbie]

:no: OF COURSE! How stupid was I to think you could actually fix these old damn trucks! :wall: It runs good and cycles coolant, but now I have a coolant drip. I think it's from the waterpump or the lower radiator hose. I've also seen a tiny tiny little bit leak from the bolts on the thermostat housing, but I don't want to tighten them too much as that's how I cracked the first housing. I guess I need to buy all new hoses and a new water pump. :rant:

[LarryH88bt]

Get rid of those pain-in-the-@$$ spring clamps that come standard and use good ol fashioned screw hose clamps. Then if it leaks down the line, another turn or two on the screw and it should stop leaking. And less chances of that spring clamp hitting you in the face when it slips out of the pliars as you try and squeeze the hose back in :fs1:

[87Warrior]

Newbie, did you put thead sealer on the t-stat bolt threads? Also, sounds like you need to invest in a torque wrench. IIRC the t-stat housing bolts are rated at 156 in.lbs (NOT FT LBS!). Eliminates all guess work when assembling delicate parts.

 

I love the spring clamps. If you ditch them, I will pay for postage to send them my way. I have the spring clamp pliers and will never go back to the inefficient screw style hose clamps.

[ComancheNewbie]

Get rid of those pain-in-the-@$$ spring clamps that come standard and use good ol fashioned screw hose clamps. Then if it leaks down the line, another turn or two on the screw and it should stop leaking. And less chances of that spring clamp hitting you in the face when it slips out of the pliars as you try and squeeze the hose back in :fs1:

 

I'm already using screw clamps and if I tighten anymore, they might cut into the hoses.

[ComancheNewbie]

Ok, I just replaced the water pump, so now I'm back to the engine not sucking coolant again. Last time, it took 2-3 days for the coolant to finally get sucked in. Any other tricks on how to "burp" the system and get rid of this damn air pocket that keeps forming?

[freakjeep93]

park on a hill and pull the temp sender i think is how you burp the air out