• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Does your electric fan run on the highway???

E

ebxjbob

NAXJA Forum User
Location
Snowmass, CO
Hey just searched for a while couldn't find an answer

have a 97 4.0/AW4

once I get on the highway the temp goes up to the first line above 210 and the electric fan clicks on, doesn't turn off till I get off the highway and drive easy

My 96 never did this and it dosn't seem normal

any ideas??

TIA
 
My XJ did that once. At 85+ the guage would go to the + side of the 210 mark. At this temperature the the cooling fans ran all the time. At 70 and below it would return to it's normal position; the minus side of 210.
Solution? Flush and refill cooling system and clean the radiator frontal area. This happened after I returned to the US after an 8 month project in the Caribean.
 
No, mine come on soon after I exit the highways in the deserts of AZ-CA-NV-UT when it's hot out. They come on intermittently in stop-and-go traffic in hot weather anywhere I drive. I have dual electrics with a resistor placed in parallel with the auxilliary/AC fan switch in the t-stat housing cooling a Modine two-row radiator. The switch operates a relay that brings both fans on at about 215*F, and then drops them out at about 195*F. No problems so far, even wheelin' it a bit with the air on @ 105*F+. I dont know about extended wheelin' in the heat since I have to use my Jeep for work.

Sounds like you might be runnin' a little on the lean side?
 
Last edited:
my electric fan runs whenever i click the switch :)

seriously, it is one of my favorite mods. with my cooling system in perfect condition i hardly ever get too hot, but having the fan under my control allows my to turn it on if im wheelin or something...if you leave it stock the fan comes on too late, IMO
 
EBXJBOB said:
Hey just searched for a while couldn't find an answer

have a 97 4.0/AW4

once I get on the highway the temp goes up to the first line above 210 and the electric fan clicks on, doesn't turn off till I get off the highway and drive easy

My 96 never did this and it dosn't seem normal
Click to expand...
Yeah that doesn't sound normal to me. At highway speeds you have lots of air flowing through the radiator. That should cause temps to stay around 210 unless you are going uphill, temps creep up but mine has never risen to the point the fan turns on (during highway driving).

BTW, per my FSM, the aux fan kicks on at 223* and off at 217*. I would think your 97 would be the same, but who knows....
 
It should not be getting to above 210 while on the highway in the first place. Your fan is functioning normally, but there is something else wrong with the cooling system. I might put a new thermostat before moving on to flushing and so on. I dont think a bad clutch on the mechanical fan would do this but its something else to think about.
 
sounds like a waterpump to me, as rpms rise typically the cooling gets better because the waterpump is kickin more water thru, and at highway driving this would be the most likely culprit behind bad cooling, imo.

even on hot summer days sitting at long redlights when the temp climbs, throw it in N and rev it up you can see the temp drop. a lot of folks dont believe this because they say when you rev it, more heat is produced...but the coolant is exchanging heat a lot faster. at 1700 rpm, the engine isnt producing heat 2x faster than idle, but it is pushing 2x the water.

-Tim
 
jeepnuts311 said:
sounds like a waterpump to me, as rpms rise typically the cooling gets better because the waterpump is kickin more water thru, and at highway driving this would be the most likely culprit behind bad cooling, imo.

even on hot summer days sitting at long redlights when the temp climbs, throw it in N and rev it up you can see the temp drop. a lot of folks dont believe this because they say when you rev it, more heat is produced...but the coolant is exchanging heat a lot faster. at 1700 rpm, the engine isnt producing heat 2x faster than idle, but it is pushing 2x the water.

-Tim
Click to expand...

also your mechanical fan spins faster which adds to this effect...
 
How does it sit? If you have installed a lift and the front is higher than the rear, air flowing under the front instead of over blocks air flow through the radiator, missing splash shields makes it even worse.
 
alright thanks for all the replies...

It sits at the stock hight but the endcaps and air dam are off, whats left of the spalsh shield is ziptied up there, it was doing this before the endcaps/airdam were removed (not by choice)

drivetrain is stock, tires are stock size

It runs under 210 around town usually but if i drive it hard it will go over, the fan kicks on, but then the tmep doesn't come back down, it will stay a little over and the fan will keep running until I turn it off and it gets a chance to cool

all this keeping in mind the temps have been 50 and below, it was doing this on a highway trip were my overhead console said it was 39 degrees

from the replies i'm thinking i'll do the t-stat since its easy enough
 
Last edited:
My 91 doesn't get up to 210 unless I'm doing some low speed trail riding. I put a 170 degree thermostat in it and it seems to keep it cooler. I also have a stock front skid (Maybe a radiator skid) on there wich IMO helps it cool some. My buddy has a 90 with the same thermostat and his runs hotter than mine, but does not have that skid up front... go figure.
 
Ok trying to bring this thread back....UPDATE

Put on a front skid because I have no end caps or splash shield - no change

Last week I put in a new t-stat and flushed/refilled - no change

Today I put in a new water pump - no change

Radiator looks fairly new but no proof it is...97 with 140,000 i'm thinking its been replaced or it would look ugly

When the fan does click on it has trouble bringing the temp back down, usually doesn't turn off till I turn off Jeep and let it cool

on the highway it runs at a constant 220 ish with the fan on

Again its a 97 4.0/AW4 with no lift, 30 inch KO's, no bumper end caps, front suspension skid

It was having the same prob with the 225 tires as well

I guess the only other thing to replace is the rad...must be messed up internally??

any other suggestions??

TIA
 
If you sit at idle for an extended period does your electric fan cycle on and off normally, or does it stay on like you have described?

Is your fan-clutch working? Is your serpentine belt tight enough? Is your transmission overheating? Is there a spring in your return hose?
 
Last edited:
Fan doesn't cycle normally , seems to have trouble bringing the temp down once it turns on

Trans shifts fine, don't think its overheating, how would I check

Don't know about the spring

Serp belt is tight

The cooling system seems to be trying to operating normally, but the elec fan has trouble bringing the temp back down and it def shouldn't be running on the highway

I'm stumped
 
Last edited:
Sounds like you've still got some restricted waterflow. Does your radiator look and feel like it has plastic tanks on each end of a single row non-painted core? Is there any nasty crud built up in the bottom of your overflow bottle? I'll bet you've got the original radiator, and it shouldn't be very hard for you to tell for sure. If so, you might want to consider upgrading to a Modine HD two-row and making sure your fan-clutch works. If you grab the lower radiator hose and give it a squeeze, you should be able to tell if it has a spring in it. The spring is there to keep the hose from collapsing. Also, you need to make sure you're using a properly functioning 16 psi radiator cap.

Do you ever get a whiff of coolant when it's running? Need to keep adding periodically? Any known leaks?
 
You need to pay careful attention to the AW4. If it is over heating, therre is a good chance it will cause the engine to overheat as well. The fact that it overheats at highway speeds tells me there is something seriously wrong with your XJ.
Check for air blockage in front of the AC cooling unit and between that and the radiator. Some uses a water hose and back wash through the radiator and the AC unit. Remove the grill from the front and do a touch test on the radiator end caps on both sides of the radiator. If the AW4 is the culprit, that side will be hotter than the inlet side of the radiator.
I did this when my AW4 had problem. It turned out to be the shift solonoids in the tranny. One was dead. the other was marginal.
I have dual electric fans in my XJ. Using a mechanical guage in the thermostat housing, the water leaving the engine never get past 200 at highway speeds in South FL summer with the OEM 195 thermostat. The fans come on at 210.
There are other advice here in this thread. Work them through one at a time.
Hope this helps.
 
It doesn't look like the original radiator, looks very clean

I've already done the t-stat/ flush and fill and I just did the water pump

It was like 70 here today in mass and the jeep was pretty much just running between 210 and the first line after it which is what 220? with the fan on

Problem now is I have no $ after doing the waterpump and i'm in college and not presently working

When it was colder out around here it wouldn't go over 210 around town so i'm hoping when temps go back down to normal it will go back to running like that

btw no coolant smell, no leaks, never need to add any coolant

I'm going to take the grill off and see if the trans may be overheating
 
I'd also suggest taking a good look at the lower rad hose; if it's on it's way out and doesn't have a spring, then the higher RPM's would make it partially collapse from the suction.

The 'bad tranny overheating' angle is a new one for me, I never would've thought of it!

Hope you find out what's causing it...

:)
 
If the higher RPM's would cause that, it would explain why revving it up and trying to circulate the coolant wouldn't drop the temp

I will check that as well

Thanks for all the replies
 
You must log in or register to reply here.

Similar threads

R
Fan not turning on when hot- fan works!
Replies
2
Views
2K
JMA_2001XJ
J
C
Before I Get the Head Milled (Overheating)
2
Replies
31
Views
8K
maxbraketorque
M
M
New and need help
2 3
Replies
41
Views
9K
Evan03
E
M
New to my XJ & wrenching - How to choose parts and what to prioritize?!
2
Replies
28
Views
4K
flyin_ryan
F
L
Fuel Pump Wiring
Replies
5
Views
1K
Lordhelemt
L
Back
Top