2 different thermostats same problem.

Ok, I have an 89 Cherokee 4.0, closed loop cooling system, a while back I over heated, so I changed the thermostat heater hoses upper an lower rad hoses thermostat housing water pump and dropped new coolant in it, I did the hoses cause when I wiped my finger inside them to feel for crud my finger came out black. Anyway, switched everything out, read up how to burp the cooling system. I felt I did everything right...
Now here's my delimma... It don't matter how Long I've been driving my temp looks like this

It may fluctuate a little but up or down but not much. Sure it doesn't seem bad for summer but at 35 degrees my jeep will sit on that middle line and all I can do is pray for heat to come out of my vents!

Also something else I noticed on my xj and I don't know how to approach it is this


No heater control valve... I found the vacuum hose plugged off and tucked away...
I understand that summer is almost here but I wouldn't mind everything to function like they are suppose to. I really don't wanna take my jeep to a shop and overcharge me for a simple fix.

Has anyone done the dodge Dakota/Durango inline radiator cap mod? Does that make things easier to burp the system?

fixed your thread title... apostrophe misuse is a pet peeve of mine :eyes:

That looks like the goofy old RENIX cooling system. I haven't the slightest clue how to work with that, I hate em, my first instinct would be to convert to the 91 and later open cooling system but obviously they can work since they were factory at one point...

Have you verified your temp using an IR gun? What temp thermostat are you installing? What brand? Have you checked and cleaned your grounds? The OEM temp gauge relies on the engine to firewall and engine to battery to left inner fender ground paths for an accurate reading, if yours aren't in the best shape you can get pretty inaccurate readings on most gauges.

I agree that if 2 different t-stats didn't change the indicated temp that you need another means of reading the temperature to see what's going on.

Having buggered up piping doesn't help sort it out any.

I've changed the sending unit on the block but not the one on the radiator, to my understanding the radiator one is used for the e-fan.
The thermostats I'm buying are autozone thermostats, I checked the one I just installed by placing in hot water and heated it until it started to open up which showed me that it opened at the proper temperature which is 195 degrees.
I have not verified the temp using an IR gun. I do have one but the batteries are dead, if I were to test my temp. Where would be the best place to shoot? The temp sending unit?
I'll check my grounds tomorrow and sand them smooth to see if anything changes. Thanks for the new ideas of where to look

Mine sits about there and have no problem getting heat.

blubullett said:

Mine sits about there and have no problem getting heat.

Click to expand...

I think I'm going to reroute my hoses to where they have to flow through my heater core first then up into my plastic tank then back down to my water pump(or thermostat housing) that way I'm sure to get adequate heat to my vents. Then maybe change it up to where i bypass the heater core all together for the summer.

Unless someone can chime in explaining why I shouldn't do this.

I have a meat thermometer, the one used for testing a turkey. I keep the cap off and stick it in the radiator/reservoir. With the cap off, I can see if the water is circulating and once it's doing that I can see what the temp is. Gives me a ball park figure.

Throw the thermostat in a pan of water, just before boiling, the thermostat should be all the way open, or you use your meat thermometer($5).

Looking at the parts book, it looks like you can put the thermostat in backwards. Just a thought.

Before you get off on a tangent, let me relate my experience. I have used/replaced 3 Stant Super Stats which I though were high quality to solve your exact issue. It wasn't until I replaced the last one with a factory 83501426 stat that my wife's XJ now warms up to the proper temp and quite quickly.

A good mod to make, and doesn't relate to your issue at hand, is to replace the crappy replacement on your coolant jug with a Volvo one. Part number 703-1396 from Napa.

I don't even know what brand my stat is right now. The previous one is a duralast and worked great, but it came out with the motor when deathwobble cracked the block mounts off. The current one came from some hole in the wall parts store in Keene NH, I don't remember what brand it was.

Stop buying autozone garbage. Problem solved

Ok, so I started it up and let it idle for a good 15 minutes, it's about 68 degrees out and the highest I could get my temp up to was 187 degrees and that's water temperature. That's what was dribbling out of the hole at the top of my coolant tank. The brass fitting was right around 180... So idk, dependant on where I measured from on the thermostat it read as high as 207, but that still wouldn't kick on my e fan... And once I revved the engine the coolant temp would drop cause it was flowing thru my radiator... I'm out of ideas, maybe I'm just running cool... I'll have to wait til summer to see if things change

Which brand thermostat are you using now?

Just a duralast, but I tested it in boiling water and it opened up at 190-195

I'm done with anything other than Mopar after my last 3 experiences.

And what exPierence was that?

MaxxXJ said:

And what exPierence was that?

Click to expand...

Post # 8.

Oh sorry, thank you, how much for a mopar one?

2X_01_Jeeps said:

Thermostat outlet as long as it's not really shiny (IR isn't accurate for shiny surfaces). After all, we're wondering about the thermostat more than the sender. When it's fully warmed up and circulating good hot water the upper radiator hose will be at thermostat temp too.

Click to expand...

my thermostat housing is nice and rust colored =) its new but i didnt paint the cast and first sign of moisture made it rust.

the large upper radiator hose never saw above i wanna say 170, i shot one side of the radiator corners through the grill at 170 and the driver side at 140ish

ive also been thinking about this... because i dont have a heater bypass valve i was going to add a ball valve on the inlet side of my heater core and block off flow into the heater and allow direct flow into the tank, out the tank and into the water pump. i would eliminate my heater core this way with the valve closed but that wouldnt be a bad thing for the summer when i dont have AC. eventually im going to convert to an open loop system but until i have more money this mod will have to wait.

Heater valve has nothing to do with your issue. Save your money and don't add a valve.

$16 for stat from dealer.