What's with the coolant sensor? - JeepForum.com
 
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post #1 of 7 Old 08-21-2017, 03:59 PM Thread Starter
Mattyjm
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What's with the coolant sensor?

My '00 WJ Laredo, 4.0L i6/42RE/242 has a very nice coolant sensor on top of the reservoir that tells me when she needs a little. About every six weeks I have to dump a third of a gallon or so in the reservoir and the message erases from the EVIC. Nice. Good going, Jeep!

My '04 WJ RM Edition, however, does not. So, today, it gets a little warm on the way home so I stopped and filled the empty reservoir with coolant. The temp went back down to normal, but when I got home, I let her cool down while working on my '00 WJ's rear end. When I got it all back together and on the ground, I started up the '04. I pulled the radiator cap and filled the rad. with coolant while it burped out a little air. When I was satisfied, I capped the rad. and refilled the res. and now she's fine again.

My question is, Why in the world would Jeep engineer that low coolant sensor OUT of the later WJs? Dummies!


I looked over there <- one day and it said "Senior Member" and I was like...."Naaa
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post #2 of 7 Old 08-22-2017, 05:42 AM
HarryH3
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First, you need to determine where the coolant is going. It's leaking out somewhere. It's a closed system that should not need to be topped off once the air is bled out of it.

If Jeep left out the sensor on later models then they probably did so to save a couple of dollars per vehicle. It's known as "value engineering", which really means how can we manufacture stuff cheaper? Someone at Jeep probably determined that cooling system problems are so close to zero during the warranty period that they could save a bit of money be leaving that sensor out. Jeep doesn't care what happens after the warranty expires. They don't get the bill for that.
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post #3 of 7 Old 08-22-2017, 05:54 AM
Double E
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Quote:
Originally Posted by HarryH3 View Post
First, you need to determine where the coolant is going. It's leaking out somewhere. It's a closed system that should not need to be topped off once the air is bled out of it.
^ THIS.
Stop work on all other stuff and figure this out. It may be a rad cap, radiator side tanks are cracked or some other issue but it's going to empty your wallet if you let it continue. Reservoir should NEVER be empty on a system that's holding pressure and not leaking.

'04 Freedom Edition HO & '04 Overland HO (previous '00 Laredo 4.7)
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post #4 of 7 Old 08-22-2017, 07:47 AM
wjjeep19
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What the other two said above me.

You shouldn't be needing to add coolant at all. Sounds like you got two jeeps to diagnose.

You shouldn't be relying on a sensor anyway. Sure it sucks Jeep did away with it but you shouldn't need to be adding coolant anyway.

In the mean time, you need to check your coolant level more often until you get them fixed.

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post #5 of 7 Old 08-22-2017, 07:36 PM Thread Starter
Mattyjm
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I finally found the leak today in the '04 RM Edition. The radiator was cracked in almost the same place that my '00 was three years ago. We got rained out early from work today, So I figured I'd get a new radiator and have plenty of time to install it.

I stopped fighting it at 8:45 tonight. Had ENOUGH!. After fighting the rear axle wheel bearing on the '00 install over the weekend then finishing it yesterday morning, I thought I'd have an easy go with the rad. swap because I've already done it three years ago in the '00.

Tomorrow, I'm going to completely dismantle the front end of the '04 and put the rad. in after working a 10 hour shift. I do not remember the '00 rad. swap being this difficult. We're so close to getting the new one in....yet so far away....an inch might as well be a mile......thanks for any tips, tricks, or pointers that anyone could offer.

I looked over there <- one day and it said "Senior Member" and I was like...."Naaa
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post #6 of 7 Old 08-22-2017, 09:57 PM
new2site
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@Mattyjm ..... I assume it cracked at notorious filler neck area....if my new one from P.O. cracks I'll give the following a shot: Take soldering iron to crack to soften up cracked plastic area and meld in zip ties ....mix in well with radiator plastic ...smooth out and let cure. I've heard this works.
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post #7 of 7 Old 08-23-2017, 02:53 PM Thread Starter
Mattyjm
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I took the day off today and got the rad. replaced in the '04. I had to remove a lot of stuff that I don't remember removing on my '00.

All in all, the job was a complete success. No leaks, hot heat, and I know I burped ALL the air out of the system. She's now running at normal operating temp and the reservoir remains full to the fill line.

Thanks for the advice and help!

I looked over there <- one day and it said "Senior Member" and I was like...."Naaa
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