"Check Guages" while towing

I recently put a new 6" lift with 33's (4.56 gearing) on my 97 XJ. I have a Fleetwood tent trailer that weighs more than the average tent trailer (3500lbs). I decided to see how the XJ would tow it with the new lift/gearing setup. It pulled pretty darn well on relatively flat land. It ran a little bit warmer than normal, right in the middle of the 210 mark and the next mark up (220? mark). So I am kind of impressed and thinking, "Not bad!" (BTW I am keeping the automatic transmission in third and I also have a weight distributing hitch and a nice B&M tranny cooler)

I start to head to a pretty steep incline and notice the temperature rise to the 220 mark. I am keeping a close watch on the temp gauge as I am driving. All of a sudden the "Check Guages" light comes on and the temp needle immediately shoots over to the red area. WTF? I could tell that I was losing power going up the hill a little before this happened. I immediatley pulled over and let the motor continue to run and the temp guage went back to 210ish relatively quick. I popped the hood up and everything seemed OK except that I noticed the AC compressor clutch kept engaging and then shut off even though I did not have the AC on.

I was hoping someone could fill me in on what would make the temp gauge rocket to the red and "Check Guages" light come on. Also, why would the AC compressor be engaging?

Not sure about the temp. gauge, but for the AC comp., did you have your defrost on? If so, that will cause the comp. to engage.

andrewsnyder said:

Not sure about the temp. gauge, but for the AC comp., did you have your defrost on? If so, that will cause the comp. to engage.

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Yes, I did have the defrost on. I was unaware that the AC would come on then. I wonder if it was putting more stress on the motor as if the AC was on.

it would have put more stress on the motor yes, but it also would have scavenged some of the colder air from passing through the radiator to cool the coolant. the air would have first been warmed by the AC condensor before it had a chance to cool the radiator.
keep the AC off on the uphills should solve the problem I think.

Has anyone ever encountered the same thing with the temp guage shooting up to red with the "Check Guage" light coming on? I am wondering if my rig was hotter than it read the whole time. Seemed like it was good until right before the gauge light/temp in red issue happened.

normally when mine overheats it does just that, from norm temp to RED in a few seconds.
not sure why it happens, but when it does it starts warming up just a bit, little over normal, than if its going to go it just slams all the way to the redzone and the Check Gauges light comes on.
I'm sure there is an explanation, but I don't have it.

Mikey said:

Has anyone ever encountered the same thing with the temp guage shooting up to red with the "Check Guage" light coming on? I am wondering if my rig was hotter than it read the whole time. Seemed like it was good until right before the gauge light/temp in red issue happened.

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I did, however it was when I blew the lower radiator hose.

Good luck to you!!! :cheers:

Thanks for the input guys. It seems to be running like normal and without any coolant leaks or blown hoses (knock on wood). I think I just may have pushed my poor XJ a little to hard pulling a decently heavy trailer up a steep grade. I think it is time to upgrade my other small pickup to a full size for towing the family camp trailer.:twak:

Mikey

You may want to have your radiator pressure tested. I had a similar problem in my 98. I could see not leaks from the radiator or hoses but while driving under minimal loads sometimes it would do the same thing you are talking about. I ended up replacing the radiator and have had zero problems since.

Greg

If it still has the factory rad (97) it's getting a bit old for towing. I would check the fins at the bottom if they pull out with needle noise. Then replace it.
Also look to the clutch fan. Try locking it up and testing it or just replace it. They general last a bit longer but it's something to think about. Please replace with a good factory one.
Sometimes just force a down shift. But keep going.
I have pulled a 4820 LB trailer for 2 years now with 3.73 gears and a HD rad. A 2880 LBer before that bone stock in 107 deg. F. I did have to shut off the AC on the hill then.
So I would think you should do fine when things are right. Or do you just want a new pickup?

Temperature rise should not be instantaneous, it can happen fast but shouldn't happen that fast unless you have an air pocket in the coolant. Has coolant been changed recently? If you do suspect an air pocket, thorough burping of the cooling system is in order.

You may have a coolant temp sensor that is starting to go bad. I don't know at what temp your CHECK GAUGES light comes on (anybody????) but I'm pretty sure it's higher than 220. So either your computer "thinks" the coolant is at the high spec due to incorrect input (ie; bad sensor) to trigger the light or the coolant really IS at that temperature; one of the two.

Good luck...

Curious if anybody ever figured this out?

I tow a 2200 lb. camper with my 2001 XJ. 31" tires with 4.10 gears. Pulls fine until I hit an incline and then starts to get hot. When it goes, it is instantly from 210-215 range to maxed out on the gauge. Pull over and it instantly cools back down to 210 range. I'm doing a radiator swap and changing all the hoses this weekend. I was researching adding an auxiliary coolant temperature gauge and tranny temp gauge when I found this thread.

Virgil-K7AZV said:

Curious if anybody ever figured this out?

I tow a 2200 lb. camper with my 2001 XJ. 31" tires with 4.10 gears. Pulls fine until I hit an incline and then starts to get hot. When it goes, it is instantly from 210-215 range to maxed out on the gauge. Pull over and it instantly cools back down to 210 range. I'm doing a radiator swap and changing all the hoses this weekend. I was researching adding an auxiliary coolant temperature gauge and tranny temp gauge when I found this thread.

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This plus make sure the fins are clean and straight.........
http://www.naxja.org/forum/showthread.php?t=1007630

Why not add an aftermarket temp gauge so you have a better idea of what's actually going on with the Jeep ?

Virgil-K7AZV said:

Curious if anybody ever figured this out?

I tow a 2200 lb. camper with my 2001 XJ. 31" tires with 4.10 gears. Pulls fine until I hit an incline and then starts to get hot. When it goes, it is instantly from 210-215 range to maxed out on the gauge. Pull over and it instantly cools back down to 210 range. I'm doing a radiator swap and changing all the hoses this weekend. I was researching adding an auxiliary coolant temperature gauge and tranny temp gauge when I found this thread.

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do you have a trans cooler? are you using the trans line in the radiator? and is there any air bubbles in your cooling system?

what kind of shape is your cooling system in- fan clutch, aux fan, recently flushed or not, original radiator, has the rad been back flushed etc.

when i tow my old pop-up to moab from phoenix, my temps rise on the steep hills in the flagstaff az area. and thats with a cooling system in great shape- taurus fan, late model e fan, 3 core radiator hood vents, large trans cooler (bypass the radiator) and trans temp gauge. for my heep its "normal" for me to have to occasionally pull off to the side to cool down

stewie said:

when i tow my old pop-up to moab from phoenix, my temps rise on the steep hills in the flagstaff az area. and thats with a cooling system in great shape- taurus fan, late model e fan, 3 core radiator hood vents, large trans cooler (bypass the radiator) and trans temp gauge. for my heep its "normal" for me to have to occasionally pull off to the side to cool down

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Would that be "hotter than the hubs of hell" Phoenix or "rising from the ashes of an AZ summer's day" Phoenix? :firedevil