Very odd drive home....

[Brasscatz]

So as you can tell by the title, it was a very odd drive home. My a/c had been barely cool over the last month. Well, today it was back to almost cold. Miraculous. I was like, Hey! This is great!

I've been keeping an eye on my temp gauge because it's been further above 210 than normal (I really need to get in there and look at that). Well, I had been sitting in traffic and finally got to my exit and once on the access road, at a complete stop in more traffic, all of a sudden I hear an "idiot ding" and look down... my temp gauge went very quickly all the way to the max, then quickly all the way down to zilch, then crept back up to where it was... just the temp gauge... and now my check engine light is on. I was literally about a block from home and I made it home carefully, but on the way there, the gauge "cycled" like that 2 more times. I've never seen that before. Check engine light is still on too.

I know my first step should be taking it up to AutoZone or some place to get the code, but has anybody heard of this before? Any ideas on possible diagnosis? Really makes me wish I had that OBDII reader that Tony has :bang:

[Mudderoy]

So as you can tell by the title, it was a very odd drive home. My a/c had been barely cool over the last month. Well, today it was back to almost cold. Miraculous. I was like, Hey! This is great!

I've been keeping an eye on my temp gauge because it's been further above 210 than normal (I really need to get in there and look at that). Well, I had been sitting in traffic and finally got to my exit and once on the access road, at a complete stop in more traffic, all of a sudden I hear an "idiot ding" and look down... my temp gauge went very quickly all the way to the max, then quickly all the way down to zilch, then crept back up to where it was... just the temp gauge... and now my check engine light is on. I was literally about a block from home and I made it home carefully, but on the way there, the gauge "cycled" like that 2 more times. I've never seen that before. Check engine light is still on too.

I know my first step should be taking it up to AutoZone or some place to get the code, but has anybody heard of this before? Any ideas on possible diagnosis? Really makes me wish I had that OBDII reader that Tony has :bang:

Can you smell it hot? Was it low on coolant? I'm thinking your sensor may have failed.

[bigjim350]

I think it is a bad sensor and the code that set will be for the coolant temp sensor.

[Carves]

If it was overheating coolant ... and the level dropped / flashed to steam at the sensor position ... then the lack of coolant will cause a lower temp reading - despite an overheating situation happening.

Check your fluid levels first up ... but I reckon you might need a new thermostat ... if the sensor / gauge are reading right.

[Brasscatz]

Wow, fast response guys! Thanks!

No, it didn't smell hot, but it was low although not shockingly low by any means. I topped her off and let her run for a little bit. It didn't get much higher than 210 this time, but the CEL is still on. I'm going to see if I can get one of the techs at work to read it for me tomorrow. If not, I'll stop by AutoZone or Advance Auto on my way home. I kind of had the feeling of the sensor or something electrical myself since I've had weird electrical ghosts from time to time in this thing.

Carves, I didn't realize that, but I reckon that if there isn't enough water to measure, the temp reading would be cooler than it really is. And the chain of events of a faulty thermostat could cause CEL maybe?

[Brasscatz]

And if the code does in fact turn out to be the sensor, I'll be back asking where that little bugger is so I can change it ;)

[Brasscatz]

Oh also.... I think it's time I flushed out my coolant. What do you think? rofl

http://i356.photobucket.com/albums/oo7/thestalliontruck/Red%20Bandit%20XJ/IMAG0922.jpg

[XJ4IV]

yes its time... also there is a process to get the code yourself without the reader however ONCE you get the code you need to google it, Matt knows the process its like turn the key on and off 3 or 5 times then the CEL will flassh a certain number of times and thats your code i THINK thats the process matt knows it for sure as he told me!
like the CEL will flash like a couple times then pause then a couple more times when it flashes 5 times thats the last part and the 5 flashes is NOT a code...
here is a reference from youtube... and THIS guy has TONS of codes
jeep cherokee check engine light OBD1 - YouTube

[Brasscatz]

yes its time... also there is a process to get the code yourself without the reader however ONCE you get the code you need to google it, Matt knows the process its like turn the key on and off 3 or 5 times then the CEL will flassh a certain number of times and thats your code i THINK thats the process matt knows it for sure as he told me!
like the CEL will flash like a couple times then pause then a couple more times when it flashes 5 times thats the last part and the 5 flashes is NOT a code...
here is a reference from youtube... and THIS guy has TONS of codes
jeep cherokee check engine light OBD1 - YouTube (http://www.youtube.com/watch?v=c6e1Q23pGd0)

I had no clue you could do that! Thanks Scott!

[Carves]

Oh also.... I think it's time I flushed out my coolant. What do you think? rofl


Welll ... theres ya problem right there ...

Just so ya know ... most of us run water or a coolant mix ... and not peanut paste .. :p .. :D


X 2 with XJ41V ... altho personally ... I'd be stripping and cleaning/flushing it all.

Having seen that goop ... I'm thinking it could be causing a sticky thermostat ... or maybe its blocked some of the lower rad rows.

The sensor is dead easy to find ... just follow the top rad hose back to the engine - and the sensor is poking out the alloy housing the rad hose the connects to. Be gentle with it ... the connector can be a bit finicky.

Codes on a 97+ dont always show up with the key on/off process ... so a scan tool is a handy thing.

Your CEL/Code at the moment will probably turn off on its own - after a few drives with everything running properly ... Some codes are just a temporary indicator ...

..... and yep ... finding the cause of the chain of events is the biggy .. and I suspect you have posted a pic of it .. ;)

[Brasscatz]

Indeed I think I have. I looked online and found another weird test to do on the '97+... I'll post that video at the bottom of this post. I tried what he did in the video I found, and it did what his did, but no code was displayed afterwards. HOWEVER, I tried the key cycle 3 times and it flashed 12 22 55. Upon further research, I found this:

CODE 12 - Direct battery input to PCM was disconnected within the last 50 Key-on cycles. (which was true, I put in a new battery 2 weeks ago)

CODE 22 - Engine coolant temperature sensor above or below acceptable voltage.
Sooo.... does that mean I need a replacement???

CODE 55 - Completion of fault code display on Check Engine lamp.
I guess that just means it was done giving me the bad news. :)


Here's the other video I found:
http://youtu.be/mEeIuTWjdlg

[Carves]

CODE 22 - Engine coolant temperature sensor above or below acceptable voltage.


Sooo.... does that mean I need a replacement???



Nope ... not nescessarily ... it just means that at some point in time the sensor had a hiccup ... either because of a fault - or because the coolant was too hot and it was making the gauge show that.

... at this stage tho ... Im thinking the CEL is just telling you to clean out the system.

The trick now .... is to clear the code and see if its still there at the next start up.

If the cooling system is 100% .... and the code 22 keeps coming back after being cleared ... then you can suspect the sensor/sensor wiring as the primary fault.

[Brasscatz]

Thank you sir. What is everybody's thoughts on the Prestone flush and fill kit you can buy at Walmart?

Also Tony... should we make these code reading techniques a sticky? These were extremely handy for me tonight. Thanks especially to Scott for bringing that to my attention.

Here's a video of my Jeep when I did the check:

Checking OBDII codes on '97+ Jeep Cherokee - YouTube

[XJ Wheeler]

Jim, i had a bad experience with one of those flush kits. It was most likely a pre-existing problem with my jeep but i'll never use another because of it.

[4.3LXJ]

Also, you might want to check your wire to the temp sensor, it might be grounding/or near breaking.

[bigjim350]

Ive used the prestone flush and fill kit on my jeep a few times. Never had a problem with it.

[prcjeep]

i've used the prestone flush kit a couple of times. I only used the "flush solvent" once. The "t" fitting goes on the upper heater hose that connects to the thermostat housing and then you hook a hose up to it. Leave the radiator cap off and turn the water hose on... Flush til it looks clear, then turn the motor on, with high heat. Best to do it when your engine is cool. Then coolant that comes out of the radiator cap opening will be hot for a while while flushing otherwise.
As far as thinking leaving the "t" fitting on permanantly, mine held its seal longer than my hose did. My upper heater hose split near the thermostat housing a few months back.

Edit: also when i knew i had a system leak, I was able to "pressurize" the system by hooking up the garden hose to the "t" fitting and leaving the radiator cap on. slowly adding turning up the water hose pressure will show your weakest pressure point in your cooling system. Mine was the pinched seam between the radiator fins and the passenger side plastic tank. I didn't know it was leaking there but it showed up when under higher pressure.

[Brasscatz]

Jim, i had a bad experience with one of those flush kits. It was most likely a pre-existing problem with my jeep but i'll never use another because of it.

Jake, I'm interested in what your bad experience was, and what your pre-existing issue was, maybe it'll compare to mine.


Ive used the prestone flush and fill kit on my jeep a few times. Never had a problem with it.

What would possible problems be? I've heard stories years and years ago about people using some sort of flush kit and their car overheated AFTER they used it... although I think they had air in their system and didn't do it right.


i've used the prestone flush kit a couple of times. I only used the "flush solvent" once. The "t" fitting goes on the upper heater hose that connects to the thermostat housing and then you hook a hose up to it. Leave the radiator cap off and turn the water hose on... Flush til it looks clear, then turn the motor on, with high heat. Best to do it when your engine is cool. Then coolant that comes out of the radiator cap opening will be hot for a while while flushing otherwise.
As far as thinking leaving the "t" fitting on permanantly, mine held its seal longer than my hose did. My upper heater hose split near the thermostat housing a few months back.

Edit: also when i knew i had a system leak, I was able to "pressurize" the system by hooking up the garden hose to the "t" fitting and leaving the radiator cap on. slowly adding turning up the water hose pressure will show your weakest pressure point in your cooling system. Mine was the pinched seam between the radiator fins and the passenger side plastic tank. I didn't know it was leaking there but it showed up when under higher pressure.

Thanks for the how-to. I've never used a flush kit before and was curious. If I need help, maybe one day this week after you get off work you could drive across B.N.H. to Bammel Trace ;). I'd still have to get the stuff first though.

Interesting thought about using it as a leak finder :D. Hopefully increasing the pressure didn't create the leak on that side. Although I suppose that if it wasn't leaking there yet, it was weak there and would've leaked eventually.

[Brasscatz]

Also, you might want to check your wire to the temp sensor, it might be grounding/or near breaking.

Another very good idea! That's why I love this site!

[XJ Wheeler]

Jake, I'm interested in what your bad experience was, and what your pre-existing issue was, maybe it'll compare to mine.


I had hooked up the flush kit and water hose when i started my jeep and it proceeded to run as smooth as a washer full of rocks and spewing water out the exhaust along with smoke. I quickly shut off the jeep and unhooked the water. A few minutes later i started it back up and after about a minute it began running like normal, not a problem since.

What i think occurred was my head gasket is slightly weakened and it couldn't hold under the extra stress and once that stress was removed it sealed back up. I am planning on doing a top end rebuild at some point also due to my lifters sticking. I do plan on upgrading some at that time.:D

Like i said i think my gasket is weakened but using that flush kit could've taken my engine out, so for that reason i'm not risking it.

[Mudderoy]

And if the code does in fact turn out to be the sensor, I'll be back asking where that little bugger is so I can change it ;)

The sensor is on the thermostat housing.

[Mudderoy]

I had no clue you could do that! Thanks Scott!

You probably can't on a 97.

[Mudderoy]

Jake, I'm interested in what your bad experience was, and what your pre-existing issue was, maybe it'll compare to mine.



What would possible problems be? I've heard stories years and years ago about people using some sort of flush kit and their car overheated AFTER they used it... although I think they had air in their system and didn't do it right.



Thanks for the how-to. I've never used a flush kit before and was curious. If I need help, maybe one day this week after you get off work you could drive across B.N.H. to Bammel Trace ;). I'd still have to get the stuff first though.

Interesting thought about using it as a leak finder :D. Hopefully increasing the pressure didn't create the leak on that side. Although I suppose that if it wasn't leaking there yet, it was weak there and would've leaked eventually.

I think the flush kit can cause leaks via too much pressure or because of the chemical used. Usually the heater core (I think).

[prcjeep]

Thanks for the how-to. I've never used a flush kit before and was curious. If I need help, maybe one day this week after you get off work you could drive across B.N.H. to Bammel Trace ;). I'd still have to get the stuff first though.

Interesting thought about using it as a leak finder :D. Hopefully increasing the pressure didn't create the leak on that side. Although I suppose that if it wasn't leaking there yet, it was weak there and would've leaked eventually.

I knew i had a leak and suspected the radiator as I had already replaced upper/lower hoses and water pump and heater control valve.

I'll be happy to help!

[Brasscatz]

You probably can't on a 97.

Actually, I was able to. I found 2 different things you can do with the 97+ Cherokees. Should we make these checks a sticky?

http://youtu.be/mEeIuTWjdlg

Here's a video of my Jeep when I did the check:

Checking OBDII codes on '97+ Jeep Cherokee - YouTube

[Brasscatz]

Well, all symptoms including the CEL are gone as of this afternoon. Weird. I'm gonna flush the system as soon as I get some time to do so, and hope that will prevent future issues.

[Mudderoy]

Actually, I was able to. I found 2 different things you can do with the 97+ Cherokees. Should we make these checks a sticky?

http://youtu.be/mEeIuTWjdlg

Here's a video of my Jeep when I did the check:

Checking OBDII codes on '97+ Jeep Cherokee - YouTube (http://www.youtube.com/watch?v=NYz-j-HMIjI)

We can do a sticky, but it would be best if it was a NEW post.

[Brasscatz]

We can do a sticky, but it would be best if it was a NEW post.

I'm on it :thumbsup:

[Brasscatz]

I'm on it :thumbsup:

Aaaaand done. :D http://www.xjtalk.com/showthread.php?p=124246#post124246


So today, my temp gauge shot to the max for a brief second then went back to normal.... no check engine light this time, just the check gauges light briefly flashed. One of these nights when I'm not so exhausted from work I'll get some more coolant and some other stuff and get that system flushed, and I'll go from there.

[Carves]

Making sure the t'stat isnt all gummed up and sticking closed sometimes ... wont take you all that long to do ....

.... probably less time than waiting for bigjim to turn up and drag you onto his tilt tray .. ;);)

[Brasscatz]

Making sure the t'stat isnt all gummed up and sticking closed sometimes ... wont take you all that long to do ....

.... probably less time than waiting for bigjim to turn up and drag you onto his tilt tray .. ;);)

I've already lost one free tow from him for honking at him on the highway and scaring the shit out of him :D

[Brasscatz]

Weeeeell, I got her flushed out, and it's mostly clean. I didn't use the chemical, just water. After today's commute, the coolant is slightly rusty again, but I'm ok with that for the time being... I guess. Booooo

The problem now is that my temps are reaching higher than ever. Hit the mark above 210 today and really wouldn't come back down. I tried turning on the heater, driving 65-80 mph, A/C, and even coasting in neutral. Now I'm thinking thermostat as well as the coolant temp sensor (CEL came back on and the gauge did its "thing" again several times). Sitting in the Whataburger drive thru on the way home, I had it in park (those of you who don't know, Whataburger is not the fastest fast-food, but it sure is worth it :)) and I tried raising RPMs to 1700, and 2000. The gauge went lower, almost down to 210*. So... water flow? Are my plastic fins on my water pump bad? Maybe sensor, thermostat, AND water pump need to be replaced?

I should give it a good talking to... remind her that she's RED and RED Jeeps don't complain and rebel.

[bigjim350]

When i replaced my clutch on the mech fan it helped alot. Check the resistance of yours while the engine is at operating temp and NOT running.

[Brasscatz]

There is some resistance. But now my lower radiator hose is leaking. must have cracked it when I had one end off on sunday. Gonna be a long day driving....

[Mudderoy]

There is some resistance. But now my lower radiator hose is leaking. must have cracked it when I had one end off on sunday. Gonna be a long day driving....

That lower hose will burst. I would change it prior to any long trip.

[Brasscatz]

Sooo... maybe it's not leaking. I re-seated the lower hose on the radiator a little better and that may have solved my problem. MAY have solved it. We'll see as time progresses.
Still plan on changing the following at some point soon:
Water pump
Thermostat (180* suggested?)
Coolant Temp sensor
Upper and lower hoses
Upgrade to GC fan clutch just for poops and chuckles. (what year GC? up to 98 ZJ? i6 or V8?)

[Carves]

Sooo... maybe it's not leaking. I re-seated the lower hose on the radiator a little better and that may have solved my problem. MAY have solved it. We'll see as time progresses.
Still plan on changing the following at some point soon:
Water pump
Thermostat (180* suggested?)
Coolant Temp sensor
Upper and lower hoses
Upgrade to GC fan clutch just for poops and chuckles. (what year GC? up to 98 ZJ? i6 or V8?)


Humour me and explain how you flushed it ... did you do the rad, engine and heater core seperate ... or just the whole system at once ??

Did you get that thermostat out for a look ??

Have you been able to confirm the temps with anything beside that vague dash gauge ??

Leaky hose can just be a badly fitted one ... as you found .. :thumbsup:


Thermostat ratings ...

Cooking up the coolant to 195* or higher ... before allowing the cooling system to flow ... in a hot climate ... doesnt make any sense to me.

Because the stock rad is so small ... dropping a 180* in doesnt seem to make a lot of difference - except in cooler weather ... but it wont hurt anything if you do.

Maybe have a hunt around for a MotoRad 190* t'stat with a jiggle pin in it ... instead of a 195*. Stant ought to have one as well.

My system and its configuration - seems happy ... and very stable ... with a 190*.

Make sure you buy "premium" versions of aftermarket t'stats tho ... coz the "economy" ones - mean cheap ... not better fuel savings ;);)

[Brasscatz]

Humour me and explain how you flushed it ... did you do the rad, engine and heater core seperate ... or just the whole system at once ?? Did the back-flush where you hook up a garden hose to the heater hose and run the motor until everything comes out clear

Did you get that thermostat out for a look ?? Nope, but if it looks anything like the radiator cap... it's nasty

Have you been able to confirm the temps with anything beside that vague dash gauge ?? Unfortunately, I don't have any other means of checking the temps

Leaky hose can just be a badly fitted one ... as you found .. :thumbsup: HOPEFULLY found... still had some water dripping, but couldn't confirm from the same place. Could have just been run-off from earlier


Thermostat ratings ...

Cooking up the coolant to 195* or higher ... before allowing the cooling system to flow ... in a hot climate ... doesnt make any sense to me.

Because the stock rad is so small ... dropping a 180* in doesnt seem to make a lot of difference - except in cooler weather ... but it wont hurt anything if you do.

Maybe have a hunt around for a MotoRad 190* t'stat with a jiggle pin in it ... instead of a 195*. Stant ought to have one as well.

My system and its configuration - seems happy ... and very stable ... with a 190*.

Make sure you buy "premium" versions of aftermarket t'stats tho ... coz the "economy" ones - mean cheap ... not better fuel savings ;);)

[Carves]

Some thoughts for you then ....


Original temp spiking issue ... I'll stick with the t'stat maybe being, all gummed up and not opening properly ...

So removing it, knocking out the centre, and refitting the flange - as a temporary fault finding exercise ... Will either confirm the t'stat as the issue ... or lead you on to other issues ... like a dodgy CTS.

You're buying a new t'stat anyways ... arent you ??.. ;);)

Higher temps after flush ... Coolant quantity in the system and air pockets is the first thing that comes to mind ... altho if the rad cap is working properly the system should self bleed after a coupla warmup/cool down cycles.

Other thing is that maybe, flushing it has caused a blockage ... and its an individual component, reverse flush, thats needed ??

If I dont replace a rad/put it in for rodding the tubes ... I'll do a quick and dirty reverse flush of the rad by removing it, stand it on its end ... and run water from the outlet side to the inlet.

[Brasscatz]

Some thoughts for you then ....


Original temp spiking issue ... I'll stick with the t'stat maybe being, all gummed up and not opening properly ...

So removing it, knocking out the centre, and refitting the flange - as a temporary fault finding exercise ... Will either confirm the t'stat as the issue ... or lead you on to other issues ... like a dodgy CTS.

You're buying a new t'stat anyways ... arent you ??.. ;);)

Higher temps after flush ... Coolant quantity in the system and air pockets is the first thing that comes to mind ... altho if the rad cap is working properly the system should self bleed after a coupla warmup/cool down cycles.

Other thing is that maybe, flushing it has caused a blockage ... and its an individual component, reverse flush, thats needed ??

If I dont replace a rad/put it in for rodding the tubes ... I'll do a quick and dirty reverse flush of the rad by removing it, stand it on its end ... and run water from the outlet side to the inlet.


Thanks Carves. I did make sure to burp the system until I didn't see bubbles for several minutes, although it is entirely possible that I didn't get all the air out. The back flush caused everything to come out of the top of the rad, and then I removed the lower hose and ran water from top to bottom too. Did both twice.

I figure that since I definitely need new hoses and (I forget to mention earlier the very, very, very slight 'hissing' noise I heard coming from around the tstat housing and water pump area... but no visable water/steam seeping), I might as well replace everything while I'm in there and get into the cooling system once instead of multiple times.

[Carves]

........... I might as well replace everything while I'm in there and get into the cooling system once instead of multiple times.


I tend to do it that way ... ;)


http://i1143.photobucket.com/albums/n629/carves-oz/Vehicle%20Bits/CoolingItems.jpg

[Brasscatz]

Alrighty... so today was my highway test (driving to and from work) and everything seemed fine. Needle got above 210, but never to the next mark. I consider this a small success, though not ideal. I felt the hood after driving and the hood wasn't nearly as hot as it had been before I replaced all these parts, which leads me to ponder accuracy of my gauge. (OBDII scanner is in the mail :D) On my second trip (I make multiple trips through my work day) the gauge went nutso again and dropped way down and my check engine light came on again with the same code - coolant temp sensor voltage too high/low. I did replace the coolant temp sensor so now I'm thinking my wiring is bad? Any other suggestions? Relay? Some module? I don't really know.

OH! My a/c was much "colder" than it has been which also leads me to believe that I'm running cooler than the gauge is leading on. Could also be the nice purty weather we had today too...

[Jeepster19]

Definitely sounds like a bad wire or loose connection.Do a continuity test and wiggle the wire as you do so to see if you loose the connection.