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Still Overheating...

799 views 12 replies 7 participants last post by  oct7brian 
#1 ·
Hey guys. I've been having trouble with overheating for a while now.....after 10 minutes from a cold start i was getting the coolant temp high indicator on the dash....i found and changed the coolant temp sensor. After about 15-20 mins of idling now, the light STILL comes on. Though now i believe that it IS overheating because in the rain, the hood steams a lot, and the middle of the hood is DRY....I don't know what else to check.....i know my aux fan doesn't work...i tested it right to the battery, and it worked, but it won't come on by itself. Don't know what's wrong. I'd appreciate any help. -shawn
 
#2 ·
If you need an auxilary fan, you must be in a really warm climate. Having your signature would be helpful. From my own experience, a t-stat that is not functioning properly, a bad radiator cap, a clogged radiator, old fluid, or lack of fluid are the most likely problems. Has the cooling system ever been power flushed? Some will say just use a t in the heater hose, but that only flushes one direction. The power flush goes opposite of normal fluid flow and does a much better job. Relatively cheap service for what you get. T-stats are cheap and easy to replace, so maybe give that a try. Most radiator shops will test your system for you for free or a very small fee. Give a shop a call and ask some questions on service recommendations. Good luck and keep us posted in case it turns out to be some other problem. :thumbsup:
 
#3 ·
Six Shooter said:
If you need an auxilary fan, you must be in a really warm climate. Having your signature would be helpful. From my own experience, a t-stat that is not functioning properly, a bad radiator cap, a clogged radiator, old fluid, or lack of fluid are the most likely problems. Has the cooling system ever been power flushed? Some will say just use a t in the heater hose, but that only flushes one direction. The power flush goes opposite of normal fluid flow and does a much better job. Relatively cheap service for what you get. T-stats are cheap and easy to replace, so maybe give that a try. Most radiator shops will test your system for you for free or a very small fee. Give a shop a call and ask some questions on service recommendations. Good luck and keep us posted in case it turns out to be some other problem. :thumbsup:
I agree I'd do a complete coolant flush and change out the thermostat. You may also have air traped in the system from a locked thermostat causing steam within the engine. Go the cheap route first change everything out and see what the results are. If nothing else its good preventative maintanence.
 
#4 ·
hey thanks for the help guys. we've flushed the radiator many times.....we opened the drain plug and stuck a hose in the fill hole, and let it run for a long time....up until a few months ago the car was sitting in a driveway for 2+ years....so you're saying the aux fan isn't really necessary? right now, it's wintertime here....so it's not hot out at all.

t-stat works cuz the radiator hoses, are hot there is coolant flowing. could it be the radiator? like i said we already got a new temp coolant sensor, and after i saw that hood steaming and dry in the rain, i'm beginning to think it's something mechanical......thanks. -shawn
 
#5 ·
shawn744 said:
hey thanks for the help guys. we've flushed the radiator many times.....we opened the drain plug and stuck a hose in the fill hole, and let it run for a long time....up until a few months ago the car was sitting in a driveway for 2+ years....so you're saying the aux fan isn't really necessary? right now, it's wintertime here....so it's not hot out at all.

t-stat works cuz the radiator hoses, are hot there is coolant flowing. could it be the radiator? like i said we already got a new temp coolant sensor, and after i saw that hood steaming and dry in the rain, i'm beginning to think it's something mechanical......thanks. -shawn
This is a long shot but have you ran compression test on the cylinder and checked your oil. Maybe you have a crack in the head gasket. I had a Mazda that acted weird like that... ran hot, no coolant leak, no antifreeze in the cylinders and started up ok. It ended up being a crack in the head gasket between two cylinders and a crack in the head. Was a real B**** to figure out what was the problem.
 
#6 ·
What year/model/engine do you have? It almost sounds like you have a Cherokee with the electric fan next to the mechanical one, and the temp light instead of a gauge. If so, there's a provision for "burping" the cooling system on the back of the head. It's removing the temperature sending unit, I think. You may have air caught in the system too.

If you do have a Wrangler (which I though all came with a temp gauge?), how is the electric fan hooked up? Is it turning on, and pushing/pulling the air in the right direction? Is your radiator cap making a good seal? You can try running a 80% water, 20% antifreeze mix temporarly. Water is a better conductor of heat than the antifreeze, but it will start corrosion in the system if left in too long. Do you have an A/C condenser in front of the radiator? You might have some stuff caught in between the two, like leaves or dirt, causing insufficient air flow.

When you flush the coolant system, there are some plugs on the bottom of the block that you can remove, it should drain all the stuff from inside the engine. You might have some stuff that settled in the water passages, restricting flow.

A test you can do on your radiator to make sure there aren't any clogs is to get a spray bottle, like a Windex bottle, fill it with water, and spray the warm radiator. If there's a spot that takes longer to evaporate than others, you could have a clog there.

Also, it will never hurt to replace the thermostat.

If it happened in a light rain, I don't think there's anything wrong with some steam coming off the hood. The heat from the engine evaporates the water off the hood, and when that humid air starts rising, it'll cool off and the water will condense some. It happens to all my cars in a light rain.
 
#7 ·
wow, i'm a friggin retard...i didn't post what kinda jeep...sorry bout that....it's a 91 YJ with the 4.0 I6.....don't have the coolant, oil, and battery gauges...just lights....

well i've actually noticed an engine oil leak when engine is running.....went under there, i couldn't really determine where it's coming from, it wasn't the drain plug.....leak was sufficent.....
 
#8 ·
Hey, sorry to jack the thread, but I've got a similar problem...

I just had my manifold replaced on my '95 2.5l. When they were doing it they busted the temp sending unit and replaced it. Now I'm running hotter than normal (about 220-230deg). Any reccomendations? Was the ols sending unit just malfunctioning the whole time? Do I need a new thermostat?
 
#9 ·
BuffaloYJ said:
Hey, sorry to jack the thread, but I've got a similar problem...

I just had my manifold replaced on my '95 2.5l. When they were doing it they busted the temp sending unit and replaced it. Now I'm running hotter than normal (about 220-230deg). Any reccomendations? Was the ols sending unit just malfunctioning the whole time? Do I need a new thermostat?
I'm no expert here, but my first thought is they put the wrong part in. Mine usually hovers around 200*. You may want to have them double check the part number or just take it back and tell them it's not right and they need to fix it for you. MHO aways.
 
#11 ·
hey

This summer I had an overheating problem too. After 15 mins of driving the Jeep would overheat. I tried everything from thermostat, fan clutch, coolant flush, water pump. Checked everything and couldn't find the problem. Finally broke down and bought a Modine 1 row alum. radiator and it fixed the problem. The problem was there was simply to much scale for the rad. to work. I asked the rad. shop if they could boil the old rad. but he told me it wouldn't be worth it since the stock rad. has plastic tops and bottoms. So for 189.00 I got the cooling problem fixed.

John
 
#12 ·
Six Shooter said:
I'm no expert here, but my first thought is they put the wrong part in. Mine usually hovers around 200*. You may want to have them double check the part number or just take it back and tell them it's not right and they need to fix it for you. MHO aways.
Well, I replaced the thermostat so after shelling out a whopping $11.89 (thermostat, antifreeze, gasket) I running at about 190 degrees. Problem solved!
 
#13 ·
Glad you got it figured out now your ready for a cold winter
 
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