rebuild of coolant system

[STERLING STINGER]

overheating still was a problem, so i tackled it yesterday.

heater core got great flow, put a garden hose on the top input and it was POURING out of the bottom...so its good imho :dunno:

replaced all collant hoses i could find

found a vacume hose to heating hose was crushed flat not letting air through, so fixed it

putting a 185 degree thermo in it today

 

i can't seem to find the thread to burp system cuz i think the info I'm looking for is in like 2 or 3 diffrent ones

 

i need to get the air out of my coolant,

ive seen someone drill a small hole in the thermostat....whats that about? burping?

then i know to park my truck on a hill as steep as i can and let it idle, but point up the hill, right? cuz down don't make sense to me

...just wanna make sure

 

thanks :thumbsup:

Paul

[Eagle]

The 165 degree thermostat is a SERIOUS mistake. That won't let the engine get warm enough for the ECU to enter closed loop mode. Your gas mileage is going to be lousy and if you have emissions testing ... it probably won't pass. The stock thermostat is 195 degrees and it's purpose is to keep the termperature UP high enough for the engine to operate efficiently. Running a colder thermostat is never a good idea.

[Geonovast]

You reeeeeaaallly need to start specifying which truck you're talking about in your tech questions. 88 and 92 are very, very different.

 

The 165 degree thermostat is a SERIOUS mistake.

 

He said 185 :hmm:

[Oizarod115]

The best way to fill it empty is to take off the upper hose and pour straight down the thermostat neck, then when the engine is I'll put the hose back on and top up the bottle. Should be able to bleed it by pointing the nose downhill and loosening the temp sender at the back if the head

[sinkrun]

Park it facing down hill don't do this when its hot (been there :doh: ) AT the back of the head on a 4.0 near the edge of the valve cover drivers side there is a coolant temp sensor/sender take the wire blug off and unscrew it. This will force the air out when coolant starts to flow out thred it back in and all done. When i did my heater core I flused it both ways thru the top and then thru the bottom hose. I can get a pic if you need will be here for about a hour yet.

[STERLING STINGER]

You reeeeeaaallly need to start specifying which truck you're talking about in your tech questions. 88 and 92 are very, very different.

 

The 165 degree thermostat is a SERIOUS mistake.

 

He said 185 :hmm:

sorry the 88

the 92 is parked in my back yard :shake:

and i did say 185....is that ok?

and anyone got pic of cooling sensor?

[STERLING STINGER]

I can get a pic if you need will be here for about a hour yet.

yes please, thanks

[STERLING STINGER]

The best way to fill it empty is to take off the upper hose and pour straight down the thermostat neck, then when the engine is I'll put the hose back on and top up the bottle. Should be able to bleed it by pointing the nose downhill and loosening the temp sender at the back if the head

truck running when i loosen temp sensor?

[Wildman]

Here's the topic your looking for :D

 

(With Pictures)

 

viewtopic.php?f=9&t=12311

 

 

 

See........alot of us 'ole timers got tired of re-typing the same thing, and Pete started the DIY section, were you'll find alot of "general information" for common up-grades and maintenance on the MJ's :yes:

 

The hole you drill is in the thermostat backing plate, to allow air to pass thru the closed thermostat. Or, the OEM thermostat from the dealer, has the hole in it, and you install it in the 12 o'clock position (up).

 

Also, don't use that 185* thermostat, get a 195* and install that, you'll have problems latter if you don't use a 195* :eek:

 

And........I use the same method that Ozzy uses for filling, and never had a problem :yes:

[ParadiseMJ]

EZ air bleeder:

 

Find a >91, 92 etc. t-stat housing at junkyard. Remove the temp sending unit, install petcock valve. Fill cooling system. Open petcock until no more bubbles. Works like a charm.

 

[AmJay]

Pour in as much antifreeze as you can. Let engine warm up. Shut engine off. Go have a cup of coffee. Come back and finish filling.

[jimoshel]

Get a petcock with a sleeve on it to slip a piece of tubing over it. We're talking less than a pint or so, but still don't make a mess in the engine compartment.

[STERLING STINGER]

Pour in as much antifreeze as you can. Let engine warm up. Shut engine off. Go have a cup of coffee. Come back and finish filling.

I'm doing this, thanks

[kro10000]

The Murray ultrastat sold at most auto parts stores has the hole and the "jiggle" valve in it, personally i run an oem thermostat... but i would advise only running a 195 degree tstat

[Eagle]

You reeeeeaaallly need to start specifying which truck you're talking about in your tech questions. 88 and 92 are very, very different.

 

The 165 degree thermostat is a SERIOUS mistake.

 

He said 185 :hmm:

My bad. I'll blame it on the monitor at work.

 

IMHO even a 185 is a mistake, but nowhere near as serious as a 165. It's important to remember that the purpose of a thermostat in an automobile is to keep the temperature UP. If your cooling system isn't capable of keeping the temperature down to 195, how's it going to keep it down to 185?

[STERLING STINGER]

good question, any answer to why its not staying cool?

[STERLING STINGER]

tmp unit out, all it does is rrev up my motor and no af coming out., do i leave cap on also

[CWLONGSHOT]

A word on T stats... they are defiantly NOT ALL created equal... Buy a FACTORY or one made specifically for the JEEP HOUSING. Not all will work with the jeep housing. Check it carefully, the "nose" may hit the housing and if it does it can and will cause problems.

 

I'm sure you read my thread from a couple months back on my cooling upgrades. I had temps above 210 most of thew time. It never overheated, but far too warm for my liking. In the heat of summer on the free way it would push 240 on hills or long pulls. I changed it to a 190 and a couple days later my rad froze two winters ago. (I mistakenly filled it a couple days before with a 50/50 mix or 50/50 mixed antifreeze.) The temps still ran at over 210. I suspected the gauge, but a laser temp gauge proved the hi temps.

 

Last fall I began reading about the pressure bottle that I finally installed a couple months back. My temps have never been so solidly steady. I installed a 180 stat made for the jeep housing. I also opened up the renix housing for better flow. I bought a new NAPA pump. My temps are running lo on the factory gauge but nearly spot on for the stat.

 

I DO advise against stat lower then 180, but as you have one higher its a moot point.

 

Whats the condition of your radiator? How about your block? have you flushed that with anything? (I read you did flush the heater core, a good start)

 

Then there is a fan clutch. hows the condition of it?

 

Back to your radiator... is it clean? I mean have you been In the mud and is it caked with the remnants?

 

CW

 

You posted while I was typing... what on earth did you just say???

[STERLING STINGER]

my radiator is new, i rhink if i can fill it, or take out the air, ill be cool. It was fine before, i just had a leak on a hose, so i replacwd ts while i had it ...unburped.. i got the plug off the vlock, and unplugged, when i start the truck, it is a great suction on that plug hole, and if i take the plug out even a little, it revs high

[CWLONGSHOT]

Its not the sensor you think it is... that's a vacuum port!!

 

Put it back, don't worry about that now. You have everything back together rite? Vigorously squeeze the upper hose. This will help push air thru the hoses/system and into the bottle where it will be dissipated. Be certain the bottle is full and go for a ride. Let it cool down and check the level again. It may take a couple times but the air will work its way out. Air in the system is a far bigger problem in the forums than it is in reality...

 

CW

[STERLING STINGER]

Omfg, thats funny. Thanks cw

[terrawombat]

I recommend using a 195* Stant SuperStat, especially if this is a Renix motor, which it looks like it is (you said this is the '88 right?). I've had issues with cheaper, no-name brands opening too soon and my 195 thermostat essentially becomes a 185 or lower tstat. Be careful tightening down the thermostat housing - I forget what the torque spec off the top of my head, but I've broken the housing cranking down just a little too much.

[comanche09]

I converted to 91+ style "open cooling" when I replaced my original radiator and hissing/pissing hoses and tank. Temp needle would routinely go up to 3/4 on the temp gauge (hot).

 

I bought a 195 Stant superstat tstat when I converted, but drilled two small holes in it at 12 and 6 o'clock. My temp gauge never gets to the halfway mark now. Only, between 1/4 and 1/2 max. Take alot longer to warm up.Does this sound normal? Starting to think that it is running too cool now :hmm: Sorry for the slight highjack...

[Eagle]

You should NOT have the engine running when you remove the temp sensor to burp the system. Park with the nose pointing downhill, so any air pockets will migrate to the highest point -- which will (hopefully) be that rear corner of the block. Then fill until coolant comes out of the hole, and then replace the sensor.

 

Personally, I don't do it that way. I let it heat up with the cap off the tank, until the coolant in the surge tank boils, then immediately shut off the engine and wait. After about a minute or two, as the system cools it'll start sucking coolant out of the bottle back into the system. After it stops sucking, restart the engine and repeat. Usually takes three to five cycles to purge most of the air.