My coolant runs around 210 - 215 (2001 XJ, I6 4.0, AW4) and with the warmer weather temperatures are going more in the 215 -220 range. Coolant was changed about a month ago and about 6months before that (Both 50:50 mix). I was wondering if I ran a 180 thermostat (for the summer) would that help to reduce the coolant temperature? Does any one have a write up for a manual override switch for the electric fan. Thanks for any advice.
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Thermostat
- Thread starter Tryfan
- Start date
joe_peters
NAXJA Forum User
- Location
- Grants Pass, OryGun
First, and foremost, the thermostat won't control or effect the maximum temperature that the engine is going to reach. Period. If you completely remove the thermostat, the engine will eventually reach whatever temperature it would have reached with a 160/180/195 degree thermostat.
First, always start with the BASICS--year, engine, transmission, a/c, any other related info like a winch, big-a** lights in front of the grill. Good start with the recent coolant change, but the other information is NECESSARY to get you good answers.
Waiting for your reply.
First, always start with the BASICS--year, engine, transmission, a/c, any other related info like a winch, big-a** lights in front of the grill. Good start with the recent coolant change, but the other information is NECESSARY to get you good answers.
Waiting for your reply.
- Location
- Minneapolis, MN
Why not find and fix the issue that is causing the warm temps ? Fully service the cooling system. A failing mechanical fan clutch is a common probelm.
The cooling system is just that, a system of related parts that depend on proper function from each of its component parts to keep the engine cool. Service the cooling system and replace any under-performing or suspected weak parts. Any component part of the cooling system that is not fully doing its job will stress the others and your cooling system will overheat.
-Use a flushing/cleaning solution and then drain and fill the radiator with a fresh 50/50 coolant and water mix.
-Inspect the radiator for mud/bugs/grass clogging the outside and mineral deposits clogging the inside.
-Replace the thermostat with a STANT brand 195*. Cheap thermostats are cheap for a reason.
-Replace the radiator cap if your Jeep has one. An old worn out cap will allow boil overs as the coolant flashes to steam. You will see the coolant temps suddenly jump from 210* to the Red Zone and back to 210* if your radiator cap is weak.
-Inspect/test or replace the mechanical fan clutch. A worn fan clutch will allow temperature creep at stoplights, in heavy traffic, and on the 4x4 trails. A fan clutch that “looks” OK is not the same as working OK. Consider installing a Heavy Duty fan clutch such as the NAPA #272310.
-Inspect the electric cooling fan and the fan relay. Apply 12 volts and make sure the fan runs. Exchange the cooling fan relay with one of the others similar relays. Confirm that the e-fan starts when engine temps reach 215-218*. Repair or replace the fan or relay as needed.
-Inspect/test or replace the coolant temperature sensor that activates the e-fan.
-Replace the water pump. The pumping fins can deteriorate over time and the pump will not flow enough coolant to keep the temps under control.
-Inspect/replace the radiator hoses. Make sure the coiled wire is installed in the lower hose.
If you have covered all the points listed above and still have overheating issues, inspect the head for cracks and head gasket for leaks. Exhaust gasses entering the coolant can raise the temperature of the coolant or cause steam pockets in the coolant that will temporarily block the flow of coolant
Read more about cooling systems here –
http://www.offroaders.com/tech/engine-overheating.htm
http://www.familycar.com/classroom/coolingsystem.htm
The cooling system is just that, a system of related parts that depend on proper function from each of its component parts to keep the engine cool. Service the cooling system and replace any under-performing or suspected weak parts. Any component part of the cooling system that is not fully doing its job will stress the others and your cooling system will overheat.
-Use a flushing/cleaning solution and then drain and fill the radiator with a fresh 50/50 coolant and water mix.
-Inspect the radiator for mud/bugs/grass clogging the outside and mineral deposits clogging the inside.
-Replace the thermostat with a STANT brand 195*. Cheap thermostats are cheap for a reason.
-Replace the radiator cap if your Jeep has one. An old worn out cap will allow boil overs as the coolant flashes to steam. You will see the coolant temps suddenly jump from 210* to the Red Zone and back to 210* if your radiator cap is weak.
-Inspect/test or replace the mechanical fan clutch. A worn fan clutch will allow temperature creep at stoplights, in heavy traffic, and on the 4x4 trails. A fan clutch that “looks” OK is not the same as working OK. Consider installing a Heavy Duty fan clutch such as the NAPA #272310.
-Inspect the electric cooling fan and the fan relay. Apply 12 volts and make sure the fan runs. Exchange the cooling fan relay with one of the others similar relays. Confirm that the e-fan starts when engine temps reach 215-218*. Repair or replace the fan or relay as needed.
-Inspect/test or replace the coolant temperature sensor that activates the e-fan.
-Replace the water pump. The pumping fins can deteriorate over time and the pump will not flow enough coolant to keep the temps under control.
-Inspect/replace the radiator hoses. Make sure the coiled wire is installed in the lower hose.
If you have covered all the points listed above and still have overheating issues, inspect the head for cracks and head gasket for leaks. Exhaust gasses entering the coolant can raise the temperature of the coolant or cause steam pockets in the coolant that will temporarily block the flow of coolant
Read more about cooling systems here –
http://www.offroaders.com/tech/engine-overheating.htm
http://www.familycar.com/classroom/coolingsystem.htm
Ian Christiansen
NAXJA Forum User
- Location
- Shelby Township, MI
Not to hijack the thread, but I'm replacing everthing in my cooling system currently. I purchased a Stant Superstat, 195 degrees. The factory stat has a small hole with a check ball at the 12 o'clock position. The new Stant does not. Is this a problem? 2001, 4.0, AW4, 158,000 miles.
Last edited:
joe_peters
NAXJA Forum User
- Location
- Grants Pass, OryGun
Christo on a cracker, I'm getting OLD!
My bad.
I would drain the coolant and save it. Put in a good radiator cleaner--the 3-6 hours of driving stuff, not the 15 minute stuff, follow the directions. When you replace the coolant dilute it with distilled water down to 30 ethylene glycol and 70 distilled water--run it like that late Spring through early Fall, then switch back to 50/50 by adding more coolant for late Fall through early Spring.
Check your fins for blockage--bugs, mud, dead birds or rodents, make sure the air flow is adequate.
Does it run hotter around town or on the highway? If around town, when the temperature starts climbing if you raise the rpms will it draw the temperature back down? If yes, your fan clutch may be weak.
Of course, there is the infamous 0331 casting head, cracks between cylinders 3 and 4. Any "milk shake" under the oil fill cap?
My bad.
I would drain the coolant and save it. Put in a good radiator cleaner--the 3-6 hours of driving stuff, not the 15 minute stuff, follow the directions. When you replace the coolant dilute it with distilled water down to 30 ethylene glycol and 70 distilled water--run it like that late Spring through early Fall, then switch back to 50/50 by adding more coolant for late Fall through early Spring.
Check your fins for blockage--bugs, mud, dead birds or rodents, make sure the air flow is adequate.
Does it run hotter around town or on the highway? If around town, when the temperature starts climbing if you raise the rpms will it draw the temperature back down? If yes, your fan clutch may be weak.
Of course, there is the infamous 0331 casting head, cracks between cylinders 3 and 4. Any "milk shake" under the oil fill cap?
Talyn
NAXJA Forum User
- Location
- Radford, Communistwealth of Virginia
It can bee. It lets air bleed from the cylinder head. Drill a 1/8" hole in the thermostat, install the stat with the hole at the top.
joe_peters
NAXJA Forum User
- Location
- Grants Pass, OryGun
No, on a closed system you might want to drill a hole in the flange to assist in burping air from the system, not a problem on your 2001.
The Stant SuperStat Premium's v-notch provides a small initial flow and aids in filling: http://www.stant.com/brochure.cfm?brochure=205&location_id=168
In fact, I don't drill the flange on closed system vehicles anymore because the only thermostats I will install on ANY vehicle are Stant SuperStat Premiums.
Running the lower temp thermostat will help provide a lower operating temp ... IF the radiator and fan are in good/new condition.
A stock rad and fan with a 180/185 t'stat and a minimal anti-freeze mix should give you about 200' temps for general driving - from experience.
Towing, lotsa lo-range, really hot days will soon see the temps going up again ... without a good radiator fitted.
As joe_peters said ... a thermostat only sets the minimum running temp. Only an effective cooling system prevents overheating underload ... and the basic, stock XJ system is only mediocre - not effective ... in regard to having reserve cooling capacity for the hard work.
Nothing prevents overheating if there is a faulty cooling component.
Its quite possible that its just the hotter weather causing the slight rise in running temps ... but Tim_MN's list is a good one to work through if needed.
First up ... Who replaced your "coolant" and was the mix no more than 50/50 ... 60/40 will see a rise in temps just as 30/70 will see a drop in temps.
What condition is the rest of your cooling system ??? Old and about to fail or fairly new ?
- Location
- Maurertown,Va.
On a related note,what can you do about fin blockage in the AC condensor? My 96 has 317,000 + miles of bugs packed in there, I believe that is causing a temp rise in mine during the 100*+ days we have been having here in the East
Wayne
Wayne
5-90
NAXJA Forum User
- Location
- Hammerspace
Put a water jet nozzle on your hose, and blow the fins out from the engine bay side (less work to push them out backwards than to force them through.) If you can, loosen the condenser mounts and blow it out directly.
Stretching a piece of screen behind the grille will help, if you're commonly in areas with loads of bugs. Used to do that for my old Datsun pickup 'way back when - Indiana had screeds of bugs in spring and summer...
Whatever your cooling system; after you've flushed it thoroly clean and replaced the coolant (and the thermal fan clutch - typical service life seems to be five years or so...) and checked the pressure cap, add a bottle of Redline Water Wetter to the coolant mix. I love the stuff - I've been using it for years! It's a surfactant (breaks down surface tension,) so the coolant will be able to make better contact with internal surfaces. This means it accepts more heat from the engine and rejects more heat in the radiator. I use it in anything that has a liquid cooling system with a water-based coolant!
- Location
- Maurertown,Va.
Been there and done All that. Only way to get any real force into the condenser would be to remove the Radiator. And I,m more inclined to just replace the condenser and start new.
Wayne
joe_peters
NAXJA Forum User
- Location
- Grants Pass, OryGun
Ian Christiansen
NAXJA Forum User
- Location
- Shelby Township, MI
I already had a two row CSF radiator and today I added a Flowkooler waterpump, 195 Stant Superstat, NAPA p/n 272310 HD fan clutch, Mopar lower radiator hose with the inner coil and a new upper hose. Ran great and maintained 195 degrees whether I was on the highway or city driving. Sitting in construction traffic for 20 minutes brought it up to 210, but not past, and it quickly cooled back to 195 when I started moving again. Then I did something really dumb and put a small hole in the radiator. I can get it repaired for $50. Any opinions or experiences with repaired radiators?
joe_peters
NAXJA Forum User
- Location
- Grants Pass, OryGun
Get it repaired, no problema.