Beat the Dead Horse. Overheating XJ

So you're saying pull off the crimp at the entrance to the "straw" of the overflow tank and just let it hang into the tank. Run it for a bit until the thermostat opens, rev it a few then after that clamp it back down to the straw. Correct?
 
So I've ran the Jeep multiple times with the overflow tube straight into the tank so I've gotta believe that there isn't any air left in the system...

While idling the temperature gauge still creeps up to about 230ish but not much further. While there I've checked the resistance of the temperature sensor and it corresponds directly with 212*. So either the coolant is that much warmer in the head while idling or one of my sensors isn't functioning properly. I suppose there could still be some air in there but I have no idea how...

I do know that the engine idles just a little rough, maybe one cylinder misfiring which could cause some extra heat but I'm not getting any codes what-so-ever. Once I'm above idle the Jeep runs just fine. There doesn't seem to be any loss of power. Could this be because of the Comp camshaft? And say this was just cylinder 6 that was misfiring, would it cause the temperature to rise that much in the vicinity of the temp Sender? Would that still allow the coolant temperature at the thermostat to be normal, thus my normal sensor resistance?

Any info on this is greatly appreciated because I'm not really sure where to go now.

Info: 4.6 Stroker by Precision Engines, 24lb injectors, new water pump, flushed system, new temp sender, 180* stat.
 
Loosen the thermostat sending unit at the back side of the block i believe its on the driver side almost against the firewall (single wire), fill the rad until coolant starts to come out there
 
Alright, I'm certain I've gotten every bit of air out of the engine, and because today was a hot one.... It got hot.

I let the gauge get up to about 230 then checked the resistance on the temperature sensor and it was corresponding to about 230....

I have noticed that my radiator has a very slight leak which I had never noticed before and have no idea why it wants to start now. It appears to be coming from the passenger side where the plastic meets the metal (piece of crap...).

I'm going to order a new aluminum 3 core radiator tomorrow most likely. Hopefully this will solve both problems. Anyone have any suggestions of where to get one? I'm looking at DPG right now and their prices seem fairly good.
 
I think radiator barn was where Chris (cltdba) got his.. a big enough pin hole in the rad will do it every time.. cooling system pressure testers are nice. btw, for the record, I was at PAP and it was hot as a firecracker down there and the jeep with cooling issues prior, the thermo outlet where I have my sender relocated, never went over 190-200 (200* on the gauge) according to my IR thermo is 210). even in traffic.
 
aha! i think i know. i ran a 180 degree tstat in my 6 for about 7 months and on the hot days it would creep past 210 during idol. when winter time came i changed back to the 195 and im running that now. no problems going past 210. what i think may be happening is the tstat is opening at 180 but it will continue to stay open. so the cooling system cant have cycles and give the radiator and adequate amount of time to cool whats in there. whereas with the 195 it opens later and doesnt flow as quickly. i would try switching to a 195 and see what that does
 
gt500swim said:
aha! i think i know. i ran a 180 degree tstat in my 6 for about 7 months and on the hot days it would creep past 210 during idol. when winter time came i changed back to the 195 and im running that now. no problems going past 210. what i think may be happening is the tstat is opening at 180 but it will continue to stay open. so the cooling system cant have cycles and give the radiator and adequate amount of time to cool whats in there. whereas with the 195 it opens later and doesnt flow as quickly. i would try switching to a 195 and see what that does
Click to expand...
yep.. but i've got a 195 in there now. temp gauge must still be wrong, IR is right on 210-214 like it ought be.
 
Okay, so I haven't been able to work on it because my tranny crapped out on me about two weeks ago. Hopefully that isn't too much of a problem to fix.

Aside from that, when I went in to swap the radiator that came with the jeep (because the tank was leaking ever-so-slightly) I found out that it was only a single core.... Could explain why it wasn't doing all that well at cooling before it started leaking. So I put in a two core from an Automatic XJ and of course that ones leaking around one of the tranny fittings, more so than my single core was. Once I get the transmission issue worked out I will be purchasing an all metal radiator from DPG for $210. I'm hoping that the triple core along with it not leaking will allow me to fill the system entirely with coolant so that the pressure can build to where it needs to be. I bought a new fan hub but obviously that didn't do the trick because the leak was probably prohibiting the coolant from reaching the proper pressure as well as letting too much air into the system.

Once I sort that all out I will report back and hopefully be on my way to FINALLY acquiring lift parts.
 
Alright, transmission is back in.

The Jeep runs great down the road. The temp gauge reads probably 195 when I'm moving so the new 3 core all metal radiator has made a difference. BUT...

When I'm idling the temperature STILL creeps up on me. I have an electric fan override switch wired in and when I flip the fan on the temp goes down... Should my Stroker still be getting this hot even with a new water pump AND the 3 core radiator?

When I squeeze the upper radiator hose there is very good pressure and there doesn't seem to be air stuck in there. I'm starting to think that it's just producing too much heat for the cooling system to keep the temp down at idle, but then again it is 90 degrees outside.
 
I'll add to this...

People think I'm crazy when I say this, but these motors will run a LOT cooler with the fan shroud intact. I can't begin to tell you how many people I've talked into putting one back on and it knock the overall temp down by 20 degrees or more. It only took me about 4 years to figure it out. :shaking: What good is a mechanical fan if there's nothing to direct the pull of air?? This applies to just about everything under the hood: if it came a certain way from the factory, leave it, because it's supposed to be there. Especially the cooling system.
 
I just bought a 1999 XJ and the guage would read about 212 for a long time and then peg out. The motor did not feel hot. I could lay my hand on the head cover and was very cool to the touch. upper radiator hose was hot but I could hold it in my hand for a few seconds before it felt too hot. I changed my coolant temp sensor and it is no longer pegging the meeter. Showing around 212 all the time now. I have issues with my heater but hopefully the sensor takes care of the guage pegging out.
 
Well this is bringing back an old thread but I'm still getting hot...

I've got a FlowKooler high flow water pump

The 3 core brass radiator that was new and I put a hole in then had patched up.

And the coolant is all new...

When I'm driving down the highway I'm perfectly fine, but when I'm stopping and going in this intense heat, the gauge just slowly creeps up... Maybe a degree a minute, and I'm getting these readings off of my OBD scanner using the "view data" function. As of lately the temp only creeps up when I have the A/C on, but the e-fan fan is running when I've got the A/C on. As far as I know if I flip my switch to turn the fan on with the A/C off, the motor stays just cool enough, but for the life of me I cannot figure out why the engine continues to get too hot just idling around with a FlowKooler pump and 3 core radiator...?
 
ty20404 said:
Well this is bringing back an old thread but I'm still getting hot...
I've got a FlowKooler high flow water pump
The 3 core brass radiator that was new and I put a hole in then had patched up.
And the coolant is all new
<snip>

but for the life of me I cannot figure out why the engine continues to get too hot just idling around with a FlowKooler pump and 3 core radiator...?
Click to expand...

Did you check the mech fan clutch? Still running the tiny shroud around it?
 
Caver Dave said:
Did you check the mech fan clutch? Still running the tiny shroud around it?
Click to expand...

The fan clutch is still the OEM one but when it's cold it doesn't spin more than a half turn... And yes the shroud is on there.
 
My mind is somewhat blown as to all of these added cooling components not being able to keep it cool while sitting still... I almost think that it may be something internal? I don't get any misfire codes, but the Comp Cam that I have gives it somewhat of a rough idle. Could a slight misfire cause the engine to run that much hotter?
 
CharlesB36 said:
runs 10 degrees cooler on average from my experience
Click to expand...
Not sure if water wetter giving me 10 degrees will be enough... I think I had the temp run up to almost 225 once when I was testing to see how hot it would get before I shut it off. Could the stock oil pump not be providing enough lubrication for the stroker?
 
but running warm sitting still and does fine in motion really sounds like an airflow issue through the radiator. id make sure your fans are true and proper. fan shroud is in tact. put an opened up shop rag in front of the grill and make sure it will hold the rag there with the suction of the fan. look for leaves, mud, or any other type of debris in front of the condenser. make sure the fins on the condenser are straight and free flowing. use some heater box tape or something similar to fill in any gaps between the fan shrouds and the radiator. its not rocket surgery, its just a cooling system!
 
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