My 93 Restoration Project
- Thread starter SirDoopYJ
- Start date
Flyer58
YJ Enthusiast
Thermostats control the minimum operating temp not the high end Your 180 degree tstat will open up at 180 degrees but the radiator is what controls the high end of the temps.
A big problem Jeeps have is getting air trapped in the engine's head creating hot spots. The system needs to be burped to get the air out and doing it on level ground may not work. I burped the air out of the system by raising the front end about 12 inches on some wheel cribs I made but you can also use ramps or park on a steep incline. Something to get the radiator up over the height of the engine. I trashed a company XJ 4.0 on the highway when it overheated and had just had a fluid change. Happened very quickly. The dealership explained the situation and what happened. They saw it all the time.
The proper thermostat should have a little loose rivet on going through the flange and should be positioned so that rivet is on the top side. It helps let air out.
A big problem Jeeps have is getting air trapped in the engine's head creating hot spots. The system needs to be burped to get the air out and doing it on level ground may not work. I burped the air out of the system by raising the front end about 12 inches on some wheel cribs I made but you can also use ramps or park on a steep incline. Something to get the radiator up over the height of the engine. I trashed a company XJ 4.0 on the highway when it overheated and had just had a fluid change. Happened very quickly. The dealership explained the situation and what happened. They saw it all the time.
The proper thermostat should have a little loose rivet on going through the flange and should be positioned so that rivet is on the top side. It helps let air out.
I am not sure if it was burped properly with the 195*F thermos. It was already done before I bought it to bring it home. When I installed my 180*F thermos and got everything back together, and filling in some coolant, I drove it to where I could incline it in order to burp it. It says my Jeep should take 11 qrts, but I think it took in only 8 and that includes the reservoir tank as well.
Right now, my temp reads right below that first big tick halfway between 100 and 210 so 140 150?. It takes awhile for it to get to this temperature sometimes. Before it would read 210 in less than 5 minutes.
Even after driving on the road for a few hours it still sits below the first big tick. Granted, it has been pretty chilly lately in Louisiana.
The only time it went over the tick was when I was riding off road and playing with the 4x4.
Trying to lower steering column to get to ignition switch. I believe it to be the issue after some help from others. I would also like to try and fix this guy. I my PRND needle is broke.
Purchase log so far:
Doors - $300 total
Softtop/hardware - $150
Temp Gauge - $39.02
Rearview Mirror- $29.99
2x Side Marker - $9.98
Taillights - $59.98
2x Front Lamp- $15.98
Lwr Steer Shaft- $124.99
8x Hinge Screws- $15.92
Cowl Wthr strip- $36.99
Wndshld Tiedwn- $14.99
2x striker pin- $7.98
2x wipers- $9.98
Hinge Bushing- $22.49
L/R Mirrors- $96.34
Grille Bushing- $9.98
2x Grille washer-
OEM Side steps- $75
Doors - $300 total
Softtop/hardware - $150
Temp Gauge - $39.02
Rearview Mirror- $29.99
2x Side Marker - $9.98
Taillights - $59.98
2x Front Lamp- $15.98
Lwr Steer Shaft- $124.99
8x Hinge Screws- $15.92
Cowl Wthr strip- $36.99
Wndshld Tiedwn- $14.99
2x striker pin- $7.98
2x wipers- $9.98
Hinge Bushing- $22.49
L/R Mirrors- $96.34
Grille Bushing- $9.98
2x Grille washer-
OEM Side steps- $75
As stated, thermostat sets the minimum temp, radiator and rest of cooling system sets the maximum temp. The 195° is proper. Mopar thermostats for the YJ aren’t truly from Mopar anymore so my typical default thermostat is the Stant Superstat 195°. I’d recommend going with something similar and of course, not the fail safe version.
As for burping, the system burps itself. A warm up cycle pushes air out as it warms up and when it cools down, the system will suck up coolant back from the reservoir. Keep coolant in the reservoir and do a few warm up-cool down cycles and it’ll naturally purge the air itself. Or, you can speed the process up by using a universal funnel kit and letting the Jeep warm up. The air will bubble out and replace itself with coolant.
Considering how much you flushed it, if you install a proper thermostat and make sure it’s all burped, I think you’ll be ok. 210° is certainly normal and where you want to be. If it goes much past that, maybe look into a fan clutch or a water pump swap.
I enjoyed ur story! I recently bought a YJ. It’s been done in the Jurassic Park theme. I plan to murder it out, but I get so much interest that I might leave it. Just took the near new radio and sound bar out as I don’t need music. Plan to sell. Have near new green carpet I’ll be pulling out too and selling. (Want no carpet). Good luck with ur project!!!! Ed
Flyer58
YJ Enthusiast
There's also the sending unit and wire connectors which can be a problem before replacing the sender try pulling off the wire connector and clean up the tab with sandpaper so it gets a good connection.
I had a temp rise off the scale but the engine was relatively cool. I found the connector loose and corroded. Also don't wrap the sending unit with Teflon tape to seal it as it needs to be grounded to the head.
You'll find lots of corrosion on bulbs, connectors and relays as you start digging into it and more often than not cleaning them up first will solve lots of problems.
Haha thanks. That is a nice looking JP Jeep you have there. You bought it like that? What are you planning with it if not JP look?
Yea, there is a good bit of clean up to do wiring wise, which was going to be my project this week since I had off, but I am still having the starting issue. Hopefully I will have that figured out tomorrow. I have it narrowed down to neutral safety switch, connection, or solenoid. I don't believe it to be solenoid though.
Alright, next update. I got the Jeep starting again Nov. 25. It could have been sooner if I checked the Neutral Safety Switch first! Oh, well. At least now I know how to lower my steering wheel and get to the ignition switch and dimmer switch. Talk about a B-word getting to the bolts underneath on the firewall.
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While looking for the Neutral Safety Switch, I couldn't help but laugh when I saw it looking at me. Hey little guy!
After running back and forth to Autozone, on the forums, and diagnosing different things, all it was, was the NSS being unplugged.
After running back and forth to Autozone, on the forums, and diagnosing different things, all it was, was the NSS being unplugged.
Dad tried to help fix the damage to the tailgate. He sanded it with a grinder and tried using a Mig Welder, but the tailgate metal was so thin, it kept making the hole bigger. He added some stuff to cover the holes that has to activate in the Sun and sanded that down. I will have to double check to what he used. Here are the before pictures:
