erykv1

Hey all,

Here's some background info on my XJ:

01 XJ, 4.0L (33's, stock gearing)

-new spectra radiator
-new stant 195 thermostat
-new upper & lower radiator hoses
-new oem water pump
-new stant radiator cap
-verified no exhaust gas contamination in coolant
-popped valve cover off to examine the head between cylinder 3 & 4
-new HD fan clutch
-new electric fan
-flushed block w/ prestone kit
-fresh 50/50 mix

-only thing not replaced is the temp sensor in the t-stat housing

Ambient temps have been around high 80's lately and even after these components have been replaced. My XJ seems to still be running between the the 210 click and the 222 click on the gauge. It doesn't overheat, but it does not run at 210 like it used to.

The only thing I can think of is that I have bypassed the heater core last winter and haven't had a chance to replace it.

Could this result in the elevated temps I'm experiencing? I've went as far as to replacing the radiator a 2nd time as well as the t-stat and radiator cap to rule out the possibility of a bad cap.

Would love to get a 2nd opinion.

Thanks in advance.

cruiser54

Nah..

drewactual

it absolutely will.... that heater core ain't nuthin but another fluid to air heat exchange that a fan pushes air through (heating it)...

now, 20*? yeah- IF you're actually using that fan pushing air through it. but 20* is certainly pushing it...

helz, a lot of cars have a strategy programmed in their PCM to open the blend door and turn the fan on full blast when approaching dangerous temperatures... Just this weekend past I taught my daughter how to knock a few precious degrees off the temperature by turning heat wide open and fan full blast, and she watched it (along with me) dip...

Ender

I always get annoyed when your temp is good but turning the motor off you watch the temp go up to an uncomfortable level... that XJ life...

BlueRidgeMark

Yeah, 20 degrees with the heater fan not moving air across it? I have trouble believing that.

That's a weird one. It might be that you removed gunk from the temp sensor and now it's giving a different reading, which may or may not be more accurate than what it was before.

Can you verify temps with an IR thermometer?

cruiser54

I've run the same Jeeps with and without heater core hooked up and no difference in engine temp.

With the blend door closed, there's no flow over the core to dissipate heat.....

Turbo X_J

It's running hot after the parts were replaced or the parts were replaced because it was running hot?

get3coffinsready

maybe you're running too lean, do you have scanner you can hook up or check the ecu codes?

erykv1

I do have a scanner and can check for codes, not sure if it will tell me my fuel trims though.

This whole debacle started after my OEM radiator started to leak at the end tank last winter. I did the radiator change, and a week after the heater core went out. I'm assuming from the higher flow from the replacement radiator which caused the old heater core to kick the bucket.

Been chasing this issue ever since. I've flushed the block with the prestone kit with the jeep running until the water that came out turned clear.

I've verified with an IR thermometer, but it never reaches 220. If it still runs hot when the temps drop further I will have to try to get to the bottom of it. Perhaps a 3 row with electric fans.

BlueRidgeMark

Are you saying that the IR thermometer disagrees with your temperature gauge?

If so, problem solved. You temp gauge is wrong. Replace the sender.



No.

1. Find the real problem and solve it. Don't mask it. The problem (if one exists) is not your radiator, unless it's defective.
2. More rows does NOT automatically mean more cooling. That is often just a marketing gimmick. Radiator design is far more complex than that.

That said, before you spend more bucks on it, see my sig. Run it for a month or so. It will get stuff out that the Prestone flush leaves behind.

Fred/N0AZZ

Part of the overheating problem while driving is with the stock gears and 33" tires and well as trans overheating from hunting for gears all the time.

drewactual

I tell you what will eat twenty degrees worth of real estate on a gauge otherwise functioning properly....

bugs...

bugs will eat that and more.

check your radiator for Shanghai'd bugs taking up lodging in the vanes... make sure your vanes are all straight and breathing... get a can of coil cleaner from the hardware store (use in hvac) and spray it down good from both sides, and let it dry off/out.

DFlintstone

Bypassing the heater core is not your problem. Not long ago I'd say it doesn't even matter BUT. Clearly it is indeed subtracting a "chunk" of heat from the coolant with the fan on high. If the balance of the heat generated, and the heat dumped is close, it can tip the scales. Right on the edge with the temp rising, tapping the coolant for all those BTU's CAN tip it. It ain't much, but even a small leak will sink any ship.

I'm running with no temp switch on my Efan. Mine is busted and I have yet to find a replacement, so I have wires I can connect to run the E-fan coming up my hill on a hot day. I've found running the heater on high let's me make the last few minutes home without needing to stop and hook up the Efan.