My new Stroker is overheating

[foggybottombob]

I have a 4.6L stroker in a '91 XJ with an 8.9 SCR. I have two conditions for overheating. I replaced the '91 electric aux fan with a '97 XJ fan which pulls a little more air with its 10 blades and I replaced the mechanical fan clutch. I live in CO where it is not really blazing hot even in the summer. The two overheating conditions are:
1) Moving slower than about 35 mph with the AC on.
2) Going uphill in the mountains where the engine needs to downshift to maintain speed. Rpms above 3K for more than a minute or so rapidly escalate the temps to 250 degrees or so.

I think that the only way to fix #1 is with a high volume electric fan in place of the mechanical one. I do have a taurus fan that I will eventually install to handle that case. But the second case is a mystery to me. I can't hear anything that sounds like detonation when the engine revs up under load going up a hill but the temp gauge will just take off going up under this condition.

I have a 3 core radiator and the hoses etc are all fairly new. I don't know of any bigger radiator I can get into an XJ. I have the AW4 and the tranny fluid is cooled through a connection to the radiator. I wondered if it would help the engine coolant temp and the tranny fluid temp to separate these and get a tranny fluid cooler. I have not read anywhere that a high flow water pump really makes any positive difference. The last thing I know to do is to put some hood louvers on but I'm not sure that these would really matter when driving at speed. Does anyone have an idea of something I can do to combat the heat when the engine is under load?

[4.whoa]

Are you using the shroud on the mech fan and is the radiator and condenser (fins) clean? I spent 4 hrs washing bugs out of my rig's rad and air-to-air last week. The driveway was COVERED in bugs

[foggybottombob]

Are you using the shroud on the mech fan and is the radiator and condenser (fins) clean? I spent 4 hrs washing bugs out of my rig's rad and air-to-air last week. The driveway was COVERED in bugs

There are no bugs in Colorado much less my radiator. The only other thing I can think of is the possibility of the PCM not providing enough fuel when the tranny downshifts but I don't know enough about how the computer works in the XJ to even guess about that. I do know that my CJ7's AMC 258 would overheat when the timing advanced too far at high engine RPMs. But you could hear the pinging in that engine and I do not hear any such noise coming from the stroker.

[lafrad]

I have seen several reports that the '3 core" brass/copper radiator is just NOT an upgrade from a "cheaper", Aluminum single row radiator.

I have one of the 1", single row aluminum rads in my '99, and I have NEVER had a problem with temps when on the move. I'm running 10:1 CR and stock injectors right now, and NO issues.

I have run across some weirdness at idle, as I have an electric fan controller that I'm still learning to program


If your ECU wasn't fueling the engine properly, you would have missing exhaust valves and/or pistons with holes in them.

[Cheromaniac]

The stock 2-row HD radiator will cool just fine. Many of the aftermarket 3-row radiators are less efficient because the rows are narrower so they're not the answer. What you need is:

1. Get rid of the clutch fan and replace it with a second electric fan. Another XJ auxiliary fan might fit if you shorten the studs on the clutch fan pulley.
2. New stock 2-row HD radiator.
3. High-flow water pump. It really does make a difference when you're going up steep hills.

[92tank]

I HAVE A 92 XJ THAT HAD OVERHEATING PROBLEMS WITH THE STOCK RAD AND 4.0, KNOW IT HAS A 4.5 STROKER. COULD HAVE BEEN THE MUD USED TO KEEP COOLANT IN. . SO I GOT A SINGLE ROW ALUM. OFF EBAY, GOT RID OF AC, MECH FAN, AND THE IDLER ON THE AC HOUSING. THAN I MOVED THE ALTERNATOR UP SO IT JUST BELOW WERE THE AC COMPRESSER WAS. PUT IN ANOTHER ELECTRIC FAN, ONLY NEED WHEN GOING SLOW. IT ONLY RUNS 170-180 ON THE ROAD.

[6TIME]

I have a 4.6L stroker in a '91 XJ with an 8.9 SCR. I have two conditions for overheating. I replaced the '91 electric aux fan with a '97 XJ fan which pulls a little more air with its 10 blades and I replaced the mechanical fan clutch.

Is the mech fan clutch thermal? If so did you confirm it's function? You can hear them kick in when the airflow temp thru the radiator heats up.

[Comanche91]

The stock 2-row HD radiator will cool just fine. Many of the aftermarket 3-row radiators are less efficient because the rows are narrower so they're not the answer. What you need is:

1. Get rid of the clutch fan and replace it with a second electric fan. Another XJ auxiliary fan might fit if you shorten the studs on the clutch fan pulley.
2. New stock 2-row HD radiator.
3. High-flow water pump. It really does make a difference when you're going up steep hills.

The 2nd XJ aux fan fits in there just fine. Here's how I did mine:

http://i182.photobucket.com/albums/x297 ... 1283102376

Also as Dino suggests, I installed a single row aluminum radiator and a Hesco hi-flow water pump. No problems since with overheating. The cowl hood helps too.

[Cheromaniac]

Do you eat dinner off your engine?

[amcinstaller]

is that a fuse holder on the pass fender by the battery? and whats the SPAL box for?

[Comanche91]

Do you eat dinner off your engine?

Only after it cools down.

is that a fuse holder on the pass fender by the battery? and whats the SPAL box for?

Yes, it's an aux fuse box I use for the H4 headlamps, power accessories (windows, mirrors, seat, etc.), and electric fans. The Spal controller is used to regulate the electric fan that replaced the mechanical fan. The other electric fan is controlled normally.

[amcinstaller]

nice. we use SPAL for our power window kits. motors are awesome, kits can NOT be beat. just all around great stuff. so, you eat off it when its cooled, but cook on it when hot?*end hijack*

[Comanche91]

nice. we use SPAL for our power window kits. motors are awesome, kits can NOT be beat. just all around great stuff. so, you eat off it when its cooled, but cook on it when hot?*end hijack*

*Continue hijack* for a sec. I have not used the SPAL power window kits, but have used the ones from Electric Life in a few Jeeps. Quality regulators, bolt-in, long lasting, and much faster than the crappy OEM regulators.

http://www.electric-life.com/shopexd.asp?id=1175

And back on-topic: Unfortunately, the engine compartment doesn't get hot enough anymore to cook with.