I agree I’m going to give it a try since it is a relatively easy conversion. I shouldn’t have to pull the radiator so we will see. I have heard from folks on this forum and people that specialize in these Jeep and engine combinations that the electric fan is the issue so thought I would give it a try. Cant hurt.
2006 TJ 4.0 Rubicon overheating issues
- Thread starter Piros1
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- over heating? tj
Rubicon88
TJ Addict
To add...your new high volume pump is in fact reverse rotation...correct?
If it's clockwise that's your problem.
If it's clockwise that's your problem.
The water pump was replaced after the heating issues began. I did not put the pump on myself but my shop mechanic did. He is more up on the Jeep stuff than I am. The pump was specifically for this engine as well. Also if you pull the cap with the engine running before it gets to hot the coolant is flowing quite well.
Rubicon88
TJ Addict
Ok...so think about what you're saying here.
Coolant flowing...
You've flushed it...
It's flowing....(that's the key)
You've even ditched the thermostat...
Perhaps something superficial is going on.
If the cooling system cannot keep coolant temperatures in check with the correct (and correctly operating) 195 thermostat, then it won't be able to with any other thermostat or no thermostat at all. Once coolant temps reach about 12-15 degF above the thermostat's rated temperature, the thermostat will be wide open, and at that point there is nothing more the thermostat can do to control coolant temps. When the thermostat is wide open, coolant temps will be dependent on other factors, i.e engine load, ambient conditions, and cooling capacity of the system in its current condition
Rubicon88
TJ Addict
Rubicon88
TJ Addict
Garages can err too. (Every single one) We get busy...sometimes things are boxed wrong...
We do try our best to keep errors to a zero level but shit can happen at times.
That said at this point I wouldn't assume anything.
Your guy might know Jeep through and through but a mistake could've been made.
The one thing you keep talking about is over heating on the trail in low range. That tells me you're putting around...idle as well...putting around..idle...and so on.
Ultimately that tells me water pump.
A marginal water pump can still flow ok at higher rpm but can't flow very good at lower rpm and or idle. (In most instances)
I know you've said you see coolant moving but you don't really know the flow performance....only that it's a "new pump" from your trusted guy.
So you're assuming it's ok.
These are not complex machines. The cooling system is really simple.
If you've no big issues like cracks or leaks....and your passages are open...it literally can't not work...
Provided your components are in good working order.
Pump, T-stat, cap, hoses, radiator...
I’m leaning towards what a few have said that the stock fan assembly is a better option. I will know if that helps by the end of the weekend after my parts arrive and I have time to install.Ok...so think about what you're saying here.
Coolant flowing...
You've flushed it...
It's flowing....(that's the key)
You've even ditched the thermostat...
Perhaps something superficial is going on.
If you have additional thoughts feel free to post.
It was having the same issue with the original pump. Not saying I couldn’t have a bad new pump. Hard to say but going to tackle this one bit at a time so I know what the issue is. Unfortunately for me this is not the most opportune time being 1500 Mike’s from home but that is usually how it goes. Nothing ever breaks down in your garage next to all your tool box.
Yes moving back to the original OEM fan is a major part of any fix of cooling issues but replacing the very likely aftermarket radiator with the Mopar is very likely the main part of the fix. Many don't understand just how much better the OEM Mopar radiator cools than aftermarket radiators do, save perhaps some very expensive types. @mrblaine often gets Jeeps that are having cooling problems and his most common fix is simply replacing the POS aftermarket radiator with the OE Mopar.
Blaine and many others are still searching for the Holy Grail of radiators... a reasonably priced replacement that cools as well and has as much cooling reserve available as the Mopar does.
Blaine and many others are still searching for the Holy Grail of radiators... a reasonably priced replacement that cools as well and has as much cooling reserve available as the Mopar does.
What about an air bubble? I know you’ve indicated you’ve flushed this thing 10 times but I wonder if there’s something in your process creating an air bubble? When I flushed mine, it ran hot in idle until I vacuumed out a very large air bubble. It didn’t self burp for whatever reason. I used a mityvac to create a vacuum and then filled.
I don’t disagree that possibly the OEM radiator may or may not be better. Realize I removed a stock radiator that was very clean and appeared to be in good condition other than it had a place it was starting to seep just enough to show minor residual, didn’t feel wet. But I was having over heat issues then.
Not sure if you if you have looked at or had your hands on a Flex-a-lite radiator but they are very well made and I don’t think I would call them a POS. They are extruded aluminum tanks and not some paper thin aftermarket junk. No plastic tanks or pinched seams. Just saying. When I get it sorted out I will post what the final outcome and fix is.
You noted that when it pegs out it is nearly always at low speeds with the a/c running. Running hot a low speeds or idling is typically an airflow problem. Are you sure the fan is running when it is supposed to? I think electric fans are typically wired with thermostatic control and some sort of "always on when the a/c is on" right? The fan may also have a high and low speed. If you are sure the fan is running as it should, (on/off, high/low speed), then swapping your OEM fan, fan clutch, and shroud might be a good direction to go next.
Beyond that the radiator would be something to consider. Even if the Flex a Lite appears soundly constructed, it may not transfer heat as efficiently as the Mopar, plastic tanks and all.
Exactly, which is the point I'm making. So far, we haven't found a reasonably priced aftermarket radiator that cools as well as the Mopar does... X2 to plastic tanks and all. My Jeep, wife's Lexus, prior BMW, and my current Genesis all have plastic tanks so it's not an indication of low quality. Not to mention none of them overheat either.
yeah, I think plastic tank/aluminum core radiators have been the norm now for nearly all cars, suvs, and light trucks for two or three decades. Had one last 23 yrs/290k miles in my 1990 Ford Ranger.
Yes the fan is wired for full time run and don’t think it has a two speed option. Originally we had it wired to the thermostat and AC but switched it to full time run. And yes it is running every time I checked it. Also at low speed I can hear it when my windows are open, pretty much all the time now that I refrain from using the AC. Thanks for the input.
Try this jack it up in the front then open the rad cap and run the engine until thermostat opens.
This will allow any trapped air in the block to exit into the rad and out the filler.
This will allow any trapped air in the block to exit into the rad and out the filler.
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