I had a similar problem on my dads 96. Changed EVERYTHING!!!!! water pump, thermostat,tune up, radiator and cap, flushed,,yada yada yada......come to find out the crank position sensor was "weak". causing the jeep to run very lean and overheat at idle or low speeds. I fought it for 3 months!!! Just an FYI and maybe another place to look. They are about $60-80 depending where you get it from.
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Still Overheating. EVERYTHING changed.
- Thread starter kc_eiland
- Start date
Thanks, I'll take a look at that too. I'm thinking of replacing a few sensors anyway, MAP sensor being one of them as recommended by an earlier post. I really want my Jeep to maintain proper temps at idle/lower speeds. Especially 4 wheeling in South Nevada, where outside temps are ridiculous already.
Will do. I planned on trying this already. I've been taking everyone's advice and trying things on my own. This is definitely on the list. Thanks.
- Location
- Southern Maryland
any chance the thermostat was installed backwards?
ParadiseXJ
NAXJA Forum User
- Location
- Paradise, CA 95969
I think that's impossible to do unless he has a hi-flow t-stat...won't fit backwards.
thanasi85
NAXJA Forum User
- Location
- Sacramento, CA
You could always just remove the thermostat and that should help for now while to further troubleshoot. Also there is the possibility that the thermostat you just installed is faulty and not opening like it should. If you do pop it out you could always drop it into some boiling water with a thermometer inside the water and see if it opens at the right temp. If it does then you know that's not the issue and running without it installed should help with it running hot for now. If it doesn't open like it should then you know that's your issue.
Pointed end is pointing out, spring is pointing in.
Did you catch that the temp does go back down when revving to 1800 RMPs while stopped?
- Location
- Southern Maryland
Yeah. Looking for simple explanations for it.
Have you bought the Stant relief cap yet? Make sure you get one that is clearly marked as a a relief cap. A cheap plain cap will not work with the overflow hose correctly.
I'm going to NAPA today after work to pick one up. I'll also be picking up a bottle of coolant system cleaner to run for a couple of days. If the NEW cap leaks as well, then I'm definitely swapping out my radiator as the fill neck my be jacked up and not allowing a proper seal. I'm also going to check the small line going to the reservoir for clogs (after it cools down of course, not trying to melt my lips to a rubber hose).
If the new radiator cap doesn't leak, then I'll just do another flush and remove the thermostat for further diagnosis.
- Location
- Southern Maryland
sounds good, one at a time
I went and grabbed a new Stant radiator cap from NAPA (as per ehall's suggestion) and also grabbed a bottle of coolant system flush/cleaner. On the way home, I decided to wash the Jeep and pressure spray the radiator and condenser real well. The Jeep maintained 210* while driving back home as it always does whenever driving. As soon as I parked in my driveway, it started boiling over from the radiator cap (the Autozone cap, not the new NAPA Stant cap). Here are a couple of pictures of the aftermath, see the coolant on the ground under the front of the Jeep.
At least the Jeep is clean but the coolant boiling over is still pretty annoying. I then waited for the engine to cool down and poured in the coolant cleaner and installed the new Stant cap from NAPA. I also verified that the line from the radiator fill neck to the reservoir isn't clogged by removing it from the radiator and blowing into it. I saw/heard the bubbles in the reservoir.
My next step is to run the cleaner for a couple of days and monitor the new Stant cap for leaks. If no leaks, then I'll flush the coolant and remove the thermostat for further diagnosis. If the cap DOES leak, then that means the radiator fill neck is jacked up and wont make a tight seal with the cap and I'll replace the radiator/flush the coolant and go from there.
I really appreciate all the support and suggestions from everyone. Thank you guys.
At least the Jeep is clean but the coolant boiling over is still pretty annoying. I then waited for the engine to cool down and poured in the coolant cleaner and installed the new Stant cap from NAPA. I also verified that the line from the radiator fill neck to the reservoir isn't clogged by removing it from the radiator and blowing into it. I saw/heard the bubbles in the reservoir.
My next step is to run the cleaner for a couple of days and monitor the new Stant cap for leaks. If no leaks, then I'll flush the coolant and remove the thermostat for further diagnosis. If the cap DOES leak, then that means the radiator fill neck is jacked up and wont make a tight seal with the cap and I'll replace the radiator/flush the coolant and go from there.
I really appreciate all the support and suggestions from everyone. Thank you guys.
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Sounds like a good plan.
When you had the cap off, did you inspect the neck? There should be a raised section that seals against the rubber gasket on the bottom of the cap. Make sure that area is free from nicks, burrs, dirt, etc... That is a pretty major boil-over - all of that should have gone into the reservoir.
When you had the cap off, did you inspect the neck? There should be a raised section that seals against the rubber gasket on the bottom of the cap. Make sure that area is free from nicks, burrs, dirt, etc... That is a pretty major boil-over - all of that should have gone into the reservoir.
I did inspect the fill neck on the radiator but didn't notice anything out of the ordinary. I also inspected the nipple for the reservoir tube on the radiator as well and that wasn't clogged/cracked.
I also noticed the Stant cap fit a lot tighter than the whatever brand I had on there from Autozone. I've been driving my Jeep around a little today and It hasn't leaked from the cap yet. The true test is when I get home from work today, as that's when my Jeep LOVES to boil over the most.
Update: The new Stant cap does not leak, so that's good.
I'm going out of town for a couple of days because I've got front row tickets to watch my San Diego Chargers hurt some Seahawks feelings. But when I get back, I'll be flushing the coolant and removing the thermostat.
Cheers.
I'm going out of town for a couple of days because I've got front row tickets to watch my San Diego Chargers hurt some Seahawks feelings. But when I get back, I'll be flushing the coolant and removing the thermostat.
Cheers.
- Location
- Southern Maryland
Does it still overheat on the gauge?
I didn't let it get that far. I only let it get to the 230* range in my driveway before I shut the Jeep off. But it was definitely climbing up there just as quick as it normally does.
- Location
- Southern Maryland
Maybe the gauge and boiling over are (were) separate problems. Have you put an IR gun on the thermostat housing to verify the gauge? If you have access to a good scanner you can get a precise sensor reading from that instead of relying on the gauge. The sensors aren't the most reliable
Have you hooked up an ODBII scan gauge to read the temperature and like ehall says measured the temperature at the thermostat housing? If you got the thermostat from Auto Zone and the upper radiator hose is cool, thermostat is next. It may not be opening all the way.
RedHeep
NAXJA #1499
- Location
- Landenberg, PA
Can you jumper the fan relay on a 2000 like you can on a '96?
If you can force the aux fan on, you'll know more about your situation. If it cools down with the aux fan on and stays cool at idle, you've got a radiator problem. Even a new radiator can be junk.
I played the overheating game for 2 years, convinced that the fancy expensive CSF radiator I bought was good and when I changed it to the Mopar HD one, all my problems disappeared.
Your coolant system is up to the task of high heat situations like highway driving, but doesn't cool when there isn't 60 mph of air through it. That sounds like a junk radiator to me.
If you can force the aux fan on, you'll know more about your situation. If it cools down with the aux fan on and stays cool at idle, you've got a radiator problem. Even a new radiator can be junk.
I played the overheating game for 2 years, convinced that the fancy expensive CSF radiator I bought was good and when I changed it to the Mopar HD one, all my problems disappeared.
Your coolant system is up to the task of high heat situations like highway driving, but doesn't cool when there isn't 60 mph of air through it. That sounds like a junk radiator to me.
