Overheating at Idle

[hivescum]

Hey everyone!

So here's my dilemma.

2004 TJ 4.0L 5spd manual.
68k miles

Overheating at Idle, stop, low speed only.

I have replaced in the past 2 weeks:
-Thermostat (with a NAPA, didn't drill hole)
-water pump Napa as well, correct impeller direction (reverse)
-fan clutch (heavy duty I ordered off Amazon, plenty of folks with good reviews on wranglers)
-serp belt and idler pulley (did it when I had the water pump off)

I've replaced almost all the coolant fluid (didn't flush though)

I've burped the hell out of it, on a steep hill , my driveway is like a 30degree angle or more..

Runs around 212 on highway.

Minute I get into stop and go traffic or idle, it creeps up, and within 15 minutes wants to redline.

Fan clutch (the new one) has plenty of resistance when hot, and doesn't spin freely cold either. It passes the spin test.

Only thing I haven't replaced is the coolant temp sensor.

Could that be problem?

When I run heat on high, floorboards, it only makes temp go up.... I thought this was odd. Usually that helps.

AC spikes heat too.

Any suggestions would be great

 

[TallGuy]

Either something in the system is restricted while under lower pressure or the temp sensor has malfunctioned. If you have a scan tool with live data, check the temp from that and compare the readings when the gauge is up.

A coolant sensor is cheap to just swap then return if it doesn't change anything.

Edit: the AC and Heat both causing temp spikes really seems like the system has a blockage tho.

 

[hivescum]

Either something in the system is restricted while under lower pressure or the temp sensor has malfunctioned. If you have a scan tool with live data, check the temp from that and compare the readings when the gauge is up.

A coolant sensor is cheap to just swap then return if it doesn't change anything.

Edit: the AC and Heat both causing temp spikes really seems like the system has a blockage tho.

I assumed a blockage or a stuck thermostat would affect the temperature at all ranges of driving high speed and low speed? I can run at high speed fine 212 is the average temperature

 

[TallGuy]

Higher speed there is more system pressure than when at idle. A blockage can be forced "open" at higher speeds when the water pump is churning faster. You may want to start with a complete system flush (or multiple flushes) and see what comes out. If you have debris in the system it will shine more light on the issue to narrow down where you spend your time and money.

 

[hivescum]

Higher speed there is more system pressure than when at idle. A blockage can be forced "open" at higher speeds when the water pump is churning faster. You may want to start with a complete system flush (or multiple flushes) and see what comes out. If you have debris in the system it will shine more light on the issue to narrow down where you spend your time and money.

Good idea.

 

[macleanflood]

Thermocure!

Thread 'Jeep Wrangler TJ Cooling System Overhaul FAQ'

Jan 23, 2017

Should I replace my entire cooling system at once?
It's a wise thing to do, yes. Let's say you buy a used Jeep Wrangler TJ with 100k plus miles on it. Well, first and foremost you have to know that as I'm writing this in 2017, your vehicle is anywhere between 20 years old (if it was made in 1997) to 11 years old (if it was made in 2006). Either way, if you have no record of the cooling system having been replaced, then you're on your stock cooling system, and even if the miles are lower, that's still a lot of time for a cooling system. Plastic and rubber wear out over time, as...

• Chris
• Replies: 331
• Forum: TJ Resources

• 

-Mac

 

[Artsifrtsi]

Do you ever drive the Jeep through mud, or has it ever been driven in mud? Check to be sure that the radiator/ac condenser fins are not plugged or restricted with mud/debris.

What is the condition of the fan shroud? If it is missing or damaged air will not pull through the radiator properly.

 

[hivescum]

Do you ever drive the Jeep through mud, or has it ever been driven in mud? Check to be sure that the radiator/ac condenser fins are not plugged or restricted with mud/debris.

What is the condition of the fan shroud? If it is missing or damaged air will not pull through the radiator properly.

Bought it a month ago. Was a mall crawler before that . No mud. Little bit of bugs on the condenser but not nasty. Gonna hose it off good while doing flush.

Shroud is intact and snugged up to radiator. I know because I had it off while I was doing the water pump and the fan clutch.

 

[hivescum]

Bought it a month ago. Was a mall crawler before that . No mud. Little bit of bugs on the condenser but not nasty. Gonna hose it off good while doing flush.

Shroud is intact and snugged up to radiator. I know because I had it off while I was doing the water pump and the fan clutch.

Welp, here goes. Gonna replace temp sensor and do a couple flushes at the same time. Fingers crossed.

 

[aston4]

Check for head gasket leak. Any bubbles in the coolant reservoir when engine running?

 

[hivescum]

Check for head gasket leak. Any bubbles in the coolant reservoir when engine running?

No bubbles in reservoir.

Flushed coolant twice with thermocure and then 4x flushes with distilled water. Final flush it ran clear.

Drained and topped off with coolant.

Also replaced the coolant temp sensor while I was there.

Burped the hell out of it. 3x , once in driveway where I worked on it. Once at the top of my driveway which is a pretty good incline, and then I drove it a bit and burped it once more.

Let it sit for a while. Then took it a few miles down the road to put gas in it. Temp here is 90. With AC on it stayed around 212-215. Til I got in my driveway and just sat while it idled with AC on.

Temp slowly climbed. Didn't redline because I shut it off before, but it would have.

I'm confused.

Literally nothing left to replace in coolant system except for a brand new radiator, and honestly it cleaned out fine and was never really nasty.

No gaps between shroud and fan.

Fan works fine.

Coolant level is good.

Radiator cap is new also.

I'm baffled.

 

[aston4]

Is the impeller in the pump definitely going in the correct direction, did you compare side by side?

 

[hivescum]

Is the impeller in the pump definitely going in the correct direction, did you compare side by side?

Yes. It is reverse flow just like the factory one I took off. I matched them up.

 

[aston4]

I'm starting to wonder if maybe the head needs to come off to examine the coolant passages, as well as for general internal inspection for cracks, etc.

Edit:. there are test kits to check for exhaust gas in the coolant. A radiator shop will often do this for cheap. Also a radiator shop can do flow rate tests.

 

[hivescum]

I'm starting to wonder if maybe the head needs to come off to examine the coolant passages, as well as for general internal inspection for cracks, etc.

Edit:. there are test kits to check for exhaust gas in the coolant. A radiator shop will often do this for cheap. Also a radiator shop can do flow rate tests.

Need this jeep for work . Can't tear down to get the head gasket off. Not seeing any bubbles. Changed oil today it was perfect, no milkiness. No oil contaminated in coolant and no coolant in oil.

 

[aston4]

Need this jeep for work . Can't tear down to get the head gasket off. Not seeing any bubbles. Changed oil today it was perfect, no milkiness. No oil contaminated in coolant and no coolant in oil.

Do you have a radiator shop nearby? Those guys are overheating geniuses.

 

[aston4]

Do you have a radiator shop nearby? Those guys are overheating geniuses. You're in MD, there should be one somewhere.

 

[hivescum]

Do you have a radiator shop nearby? Those guys are overheating geniuses.

Not sure. I will have to check. Trying to not put it in a shop for days. Gonna switch to a 60/40 distilled to coolant mix and see if that helps. I'm using 56/44 premix which is heavy coolant less water.

 

[aston4]

Also do you have the little hole in the thermostat, or did you drill one?

 

[aston4]

Not sure. I will have to check. Trying to not put it in a shop for days. Gonna switch to a 60/40 distilled to coolant mix and see if that helps. I'm using 56/44 premix which is heavy coolant less water.

Radiator shops in my experience, get you in and out same day.