am I crazy?

desertrunner

desertrunner

New member
Okay so I've been thinking... My xj runs a bit warm even tho I have a 180 tstat a new pump and 2core aluminum radiator. I keep the electric fan running and url get up above 215 while driving highway. Now I have a factory trans filler from an xj I rolled and am considering putting it on this xj and piping it from theheater hoses for a little extra cooling. Would this be a bad idea or something I should try just for kicks and giggles?
 
I don't know about hooking up a second radiator. That just feels like masking the problem.

Try the basic stuff - clean off your engine, check the hoses for kinks, make sure that you have the right mixture of antifreeze / water (too much water can boil).
 
2x

First no matter what temp thermo you put in there the PCM will try to reach 210 by leaning or richening the air fuel mix.
Second above 35 mph the natural force of air being pushed through the radiator should keep the rad cool enough that you wouldn't need a fan. My e-fan only kicks in below 30 or when slowing to a stop.

I'd look at three things.
First is the internal and external of the radiator clean? Anything blocking the radiator like a wench or mud in the fins or between AC and rad? I overheated once because of all the bugs getting caught in the radiator.
Second is your heater ore blocked or not hooked up? The heater is a part of the cooling system if blocked or terminated that bypass flow it allows, will limit cooling ability.
Lastly the water pump. It is possible to run at low temps with a failing water pump but at higher the heat created and low glow leads to higher temps. Seen water pumps with one or parts of impeller work.
 

Already decided against it.. I looked at it today and hadn't realized how small it was.

As for the basics.. I rolled my old xj and have swapped my aluminum radiator over to it that I had bought less than a year ago. I pulled the pump while I had it all apart and the interior looked brand new. I just rebuilt the head 2 weeks ago so all the fluid is brand new... But I don't know what the mixture is. But I would guess its probly some where between 2/3-1/2 water. I've read pure water will cool better but the antifreeze is needed for what the name implies and so the boiling point is higher. I've also swapped my fan from my 97 xj to the 93 and tried both mechanical fans. Heater works and have been using it in the mornings and when I do itl stay under 210 until I hit the highway. Then it heats up and passes 210. Temp sensor is brand new.

On another note it stayed cool with no efan and the oem copper radiator. My 97 xj ran at similur temps with the same radiator.. is my 2 core aluminum radiator worse than the copper? I know copper exchanges heat better than aluminum.

I'll be driving down to sandiego from LA in a few months for my honey moon and don't think the wife would be too happy about stopping to let the jeep cool so IDE like to get it taken care of ha
 
Also, after I rebuilt the head a few weeks ago it takes a really long time to heat up. It used to be warm in 10 min but now is taking 20-30
 

Go to the correct thermostat. Your headgasket may have been weeping into the water jacket before.
 

do your rad hoses have a spring in them? They could be colapsing closed if not. Its usually the bottom hose. Not super common but have had it happen. just a thought but worth taking a look
 
javcamac said:
Just return to the original fan and eliminate the electric one.
Click to expand...

Xjs come factory with both mechanical and electrical fans. Just swapped the newer fan from my 97. Still gets hotter than I'm comfortable with.. today it was around 220 but always if I turn the heater on it brings it right down to 210-212 at least ... But in early morning the heater will keep it at about 200
 
I still think its a flow problem. Coolant flow or air through the radiator. Water pump, radiator partially blocked inside or outside. Or just radiator fin count/density. You already verified the pump, and with the radiator you has similar temps in the other vehicle. I'd look at replacing the radiator. Go back to oem.
 
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My cousin runs an oem radiator and he as the same problem just not as bad. I'm thinking of removing the ac condensor... Ac doesn't work and all its just in the way so I might pull it out and see what happens
 
I've found the sweet spot for highway to be around 2000rpms. That's where it stays coolest most consistantly. If I shift to 5th and run around 1500rpm it heats up so I stay in 4th. 3rd of course is a bad idea at 65 ha
 

Okay. 2k isn't bad. Some have their rigs geared low and are above 3k to maintain 60-65. It's creates lots of heat. I believe the PCM considers this WOT.

At 1500 your lugging the engine and this isn't good over time.
 
Yeah its geared high. It has stock 3.07 gears with 31s... 2k is around 50 mph but la traffic rarely gets faster than that ha
 
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First, correct thermostat (or the water will pass through the rad so fast it can't cool enough) Also add a bottle of Redline Water Wetter. Knocked my engine temp almost 15 degrees in desert heat. Is your cat clogged? Pressure backup in the exhaust will cause overheating (and even heat gaskets to blow), improperly adjusted timing or sensors can do it too. Vacuum leaks thin the mixture too lean and can cause heatup.
 

Cat could be an issue.. just had it smogged and numbers say cars going bad. Also pretty sure it runs lean because my nox were high which is often a result of lean mixture and high compression which I foxes when I rebuilt the bar and removed a crap load of carbon buildup. All sensors are fine and no visible vaccums leaks but for the past few days islta been idling high :/ removed the condensor today so ill see what happens
 
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