Running very hot

[HOrnbrod]

Good move.  

[saveevryjp1998]

Well you didnt say you didnt want to keep it factory. 91 and up radiator. Pump and tstat stays the same and yes its 100 times easier to service the system. You can still have air in a complete overhall though but it purges with very little effort most of the time a jack under the front diff and adding coolant. Just a fyi if you keep the clised and check your pump as explained by yxmj you will still have to deal with burping the system regardless. From what it sounds nothing is wrong if you just replaced things burp it save the dough. The difference in price at autozone between renix and 91 up is like $10 as for a recovery tank you could source one from me just for shipping cost I got a 96 getting ready to crunch soon almost all assessories are still on the block, under the hood, and there is no more room to hoard parts!

[saveevryjp1998]

And for everyone else long live the renix🍌's!

[saveevryjp1998]

Lookin back at the earlier post just realized you changed your control valve. Is it the all plastic one? They are garbage I quite buying them from autozone I had em break burping the system the first time from the excessive heat. The old metal ones are awesome but pricey napa has em local get em online much cheaper and i even junkyard source em just put your finger over the vacuum line hole to check to see if it holds most of the time they work great even here in the rust belt. I have had the plastic ones fail in a year too they were way more problematic than worth the cost. The plastic gets brittle from engine heat and either crack or stop holding vacuum and on a renix (closed system) instant catostrophic cooling failure when 1 thing breaks.

[WahooSteeler]

1 hour ago, saveevryjp1998 said:

Well you didnt say you didnt want to keep it factory. 91 and up radiator. Pump and tstat stays the same and yes its 100 times easier to service the system. You can still have air in a complete overhall though but it purges with very little effort most of the time a jack under the front diff and adding coolant. Just a fyi if you keep the clised and check your pump as explained by yxmj you will still have to deal with burping the system regardless. From what it sounds nothing is wrong if you just replaced things burp it save the dough. The difference in price at autozone between renix and 91 up is like $10 as for a recovery tank you could source one from me just for shipping cost I got a 96 getting ready to crunch soon almost all assessories are still on the block, under the hood, and there is no more room to hoard parts!

Didn't say either way. Was exploring all options. Thanks for all the input. Fyi........new heater control valve is metal one. 

[saveevryjp1998]

Well i got an overflow tank for you if you want free pay the shipping if you go with updated system. I bet you just need to purge the system and get a new recovery cap. They are cheap and if not holding proper pressure could slowly leak air and cause those symptoms. If the overflow tank is old and brittle then that will for sure need changed and is most likely the cause for the air leaking into the system if all the other parts were already changed. What mqkes me think yoy haven't expelled all the air yet or have a tiny leak somewhere is how it slowly overheats. It is moving in a closed system with the lack of coolant the temp sensor still reads hot air or steam traveling in the closed system.

[saveevryjp1998]

They are picky tempermental women with just a little hot air😄.

[WahooSteeler]

5 minutes ago, saveevryjp1998 said:

Well i got an overflow tank for you if you want free pay the shipping if you go with updated system. I bet you just need to purge the system and get a new recovery cap. They are cheap and if not holding proper pressure could slowly leak air and cause those symptoms. If the overflow tank is old and brittle then that will for sure need changed and is most likely the cause for the air leaking into the system if all the other parts were already changed. What mqkes me think yoy haven't expelled all the air yet or have a tiny leak somewhere is how it slowly overheats. It is moving in a closed system with the lack of coolant the temp sensor still reads hot air or steam traveling in the closed system.

Hoping you are right. Also, pressure tank and cap are new also. 

[saveevryjp1998]

Just purge her of hot air your good. If your pump was the wrong orientation it would be far worse and much faster boilover. It sounds like you did everthing else. Make sure you are getting all the air out though with the heater control valve open and heat on high at operating temp around 210. And your passenger floor board is dry? It sometimes leaks down high up in back so it will travel down the pan under the carpet saturating underneath the carpet and not an obvious puddle on the floor mat. My first bad heater core did this and that was what plagued me on my first xj 14 years ago and taught me so much avout this darn system the hard expensive way.

[WahooSteeler]

Update: took it to a trusted shop shortly after this thread. Owner said if I could let him have it for a couple weeks he'd check several things that could be causing the high temps and just tinker with it himself when they were slow. After a couple of weeks he said it was holding good temps. He had flushed the heater core and rad, said the heater core definitely spit out a lot of crud but rad was surprisingly clean. Picked it up and drove it every day for the last couple of weeks, ran great. Oh, and he only charged me an hour labor. This past Friday drove my daughter to school, stopped back at the house before going in to work and saw coolant leaking on pass side. Popped the hood, bottle cap was loose. Mind you, the bottle and cap are new, like a few hundred miles new. Son had my car, office is 5 mins away, got no choice but to drive it. Temp gets 230ish on the short drive to work. More coolant leaking. Let it cool down, come back out 30 mins later, bottle cap loose again, pressure tank empty. Poor some coolant in, put cap on tight, go back in office. Couple hours later head to the post office and by the shop that just worked on it. He's concerned might be a blown head gasket, says bring it back this week and he'll do some testing. I'm stressed bad, dollar signs dancing in my head, not in a good way of course. New head? New motor? If new motor, switch to HO? Sell it? Yes, that was the depths of despair I was feeling LOL. By Friday afternoon I had even found an 87 w/low miles on Craigslist nearby, texted the guy to go see it Saturday thinking I can swap the motor or worst case sell mine and put my efforts in that one if it runs well. End of the day Friday make the 5 minute drive home and barely make it as she's pushing the red zone, cap already popped. Saturday morning, jump on CClub and spent a good few hours searching head gasket threads. I see in a couple different threads if pressure cap keeps popping off or coming loose, try the Volvo expansion cap. Local NAPA closes midday on Saturday, but they have it at Advance....$9. That sucker goes on tight! So between yesterday evening and @4 more times today, add some coolant to the bottle, bring it up to temp, shut down, cool off 30mins or so, repeat as the rad is slowly filling back up. Cap is holding, no leaks, no spitting or steaming anywhere. Finally doesn't need anymore coolant added to bottle. Let it run 20+ minutes, temp gauge sitting steady just below 210. Take it for a drive on the highway from one exit to the next, hit all the stop lights on the way back, never budges even to 210. No leaks in the driveway, coolant level right..........all thanks to a $9 Swedish pressure tank cap. Can't stress enough to anybody that has the closed cooling system, get this cap even if you aren't currently having problems. Man am I relieved! 

 

Oh, and I did go see and drive that 87. First time I've driven any MJ other than my own. 5 speed manual definitely shows the power of the 4.0L a lot more than my AW4. Truck is a bit rough, but mileage in the low 100s, ran great, still kicking around the idea of grabbing it and hold on to it til I'm 95% confident mine is not just teasing me and getting ready to have more problems. 

 

 

[Pete M]

sometimes it really IS the simple things.

 

long live the internet and the open exchange of ideas and experiences.