webhannet

The drip is likely your over-filled overflow tank. Of course, your system doesn't "make" water. With all your burping and filling, much of it has been expelled to the overflow tank - then to the ground.

You need to get that tank within the levels marked on the side. Still, I don't think that would affect your side-to-side issue.

While my vents don't seem bad in that sybject, there's no doubt me left defroster can't do a proper job in heavy snowstorms. My many Ford vans, Sebring, and other cars have ALWAYS had the same problem. In fact, I can't remember ever having a vehicle that could keep the left corner of the windshield clear. All of my vehicles had the same basic heat/defrost equipment layout. I blame the exchanger being on the right, and the dash ductwork being laid out as though the airflow was equal - it's not.

Rednroll

In regards to the overflow tank expelling excess fluid, this is where I'm kind of confused. The fluid isn't going over the fill max line marking. Is there a drain hole at the bottom of the tank that the fluid could come out? It seems it wouldn't be coming out from the top where the overflow goes into the tank, so that's why I'm confused.

In regards to the vents, this is what my wife and I observed recently. The passenger side vent is blowing the hottest, and then it cools down with each vent as you move more towards the left. So from hottest to coolest, here's what we observed.

Passenger far right vent: Hottest
Passenger side middle vent: Slightly cooler that passenger far right vent.
Driver middle vent: noticeably cooler than passenger middle vent
Driver side far left vent: Luke warm, coolest of all vents.

I'm expecting if there's an air pressure leak as described, the temp differences between the vents will even out more, once that gets fixed.

webejeepin

OP...good thread, well detailed, brought back some thoughts I had from about a year a go on my 08'.

My 50 cents...

I had a small leak on the original rad cap, I changed it, solved that issue.

I did my own rad flush after 150,000KMs on the clock. I did the same as you to burn the system, took my time got there.

The recovery tank had lots if sludge, I actually took it right out to clean.

I used a hand held digital thermometer and inserted it into the center stack vent, and closed the other three. Heat on HOT, fan on full and took a base line temp reading after the motor was HOT and idle. (be dam if I recall the temp off the top of my head)

Did the flush, fill burp ect...then repeated the above test as per my base line. Temp was not as hot...luke warm as you noted. Ok...odd, did more burping, not much change.

Then took it for a test drive, and then the temp jumped right up to I think it was 40* C....the usual 'Laval' heat you get from a Jeep. At the stop light it would cool off a bit to warm, then as soon as you are under way, back to Laval.

Ran this way all last winter, no issues at all.

Hope this helps the thought process.

Rednroll

Thanks for your input!!! That sounds all too familiar.

I'll re-check the overflow and see how that looks.

I think I'm about ready to just throw a new radiator at this thing. 125K miles on the clock, so I can't complain on the life I got out of the original. However, I may wait until spring for warmer weather to install it myself. I'm currently back to luke warm temps from the vents most of the time. When RPMs go above 3K now, I feel some decent heat. It used to be that when I held my hands too long in front of the vents, I would have to pull them away from the heat burning my hands. Now, not even close. There's got to be a small pressure leak somewhere and it seems the heater core is fine, because right after I burb it and made sure it is topped off, it blows out good heat and then gradually gets cooler and cooler the more I drive it.

Before I started, I took some measurements using a laser thermometer of the heat blowing out each of the vents. At idle, fan blower on high, and set to blow from front vents only, all vents open. The center vents were around 90F and the far left/driver side was 73F. That's about what I'm feeling now when sitting at idle.

webejeepin

90F while driving sounds very familiar in deed, so does the risk of 1st or 2nd degree burns on the vents LOL.

I don't recall in all the posts, and perhaps grasping at straws here....thermostat, is it original? I know some say when you replace the rad cap rule o-thumb is change the T-stat. (I broke that rule and didn't) Sorry just thinking out loud before you commit to a new rad, and yes 125K is not too shabby at all, considering the 7 big open slots that ingest all the small stones and sand

Good luck

Rednroll

No, I haven't replaced the thermostat yet, yes original of that as well. I kind of down played the thermostat because this has been going on since last winter where I've had a summer of driving in between, where I kind of assumed that if I had a thermostat problem, then I would have likely seen my temperature gauge on the high side during the summer months but my temp gauge has been rock solid in the middle once the engine is warmed up.

A recent post just came in and I think this might align with the current symptoms I'm observing. I'm going to pop off that top plastic shroud and inspect that area.

webejeepin

For sure something else to check and verify.

My temp Guage was always rock solid too, except in the winter time during really cold spells, a few times it would drop them temp to cold, force the fan on. Shutting the jeep off and on would fix that issue, so would a temp sensor swap.

I too had the mystery smell of coolant from time to time, never could find any visible signs of leaks, but every now rand then had to top up the overflow tank to the half way mark. It was an unresolved issue

Mr.T

Have you tried feeling the temperature of the two heater hoses? If there is low coolant flow (possibly from a partially plugged heater core), the return side hose may be significantly colder than the inlet (hot) side with the heat on and fan at full speed. If this is the problem, and given the difficulty of replacing the heater core, disconnecting the hoses and flushing it with a garden hose might be a easy fix.

Not with my Jeep presently, maybe it would help to check this on mine for comparison...



EDIT: Sorry, reading comprehension problem on my part. Looks like you've flushed the heater core already... Might still be worth checking the hose temperatures in case some sludge is partial plugging it again for some reason.

On a side note, suggest only filling to the minimum line on the overflow reservoir with a cold engine. Expansion from heat, plus tilting and g-forces, will spill coolant on mine if not kept fairly low when cold.

Mr.T

Rednroll, hope this test helps...

Initial conditions are 40F, Jeep hasn't run in a couple days. Hood up, drivers side window open ~8". Temperature measurements are from an infrared type thermometer, except engine coolant which is from ODBII. After startup, engine idling only. Heat high, fan high, dash vents selected.

Abbreviations:
TIM = Time in minutes after startup.
UR = Upper radiator hose temp at radiator.
H1 = Upper heater hose temp.
H2 = Lower heater hose temp.
E = Engine temp, OBDII.
A = Air temp, drivers side vent.

TIM UR H1 H2 E A
0 All temps ~40F
3 44 86 83 101 77
5 48 106 101 120 93
7 50 118 107 132 101
11 51 138 125 150 120
20 59 157 143 170 140
56 140 176 163 201/193 158

Note how quickly both heater hoses initially rise in temperature, as well as air temperature. Heater hose temperature rising at the same rate as engine temperature, indicates good coolant flow in the heater circuit.

The coolant temperature inside the heater hose must be higher than what is measured on the outer surface of the hose, and should be the same as the engine coolant measured via OBDII.

The delta temperature of the heater hoses is relatively small, indicating plenty of coolant flow. A very low delta temp might mean little air flow across the heater core. A very high delta could mean good air flow across the heater core but minimal flow through the core.

The upper heater hose felt like there was full pressure by 150F engine temperature, indicating the radiator cap is working properly.

At 56 minutes the thermostat opened. Before opening, the upper radiator hose should stay relative cold -- This indicates the thermostat is closing properly.

When the thermostat opens, the upper radiator hose temperature immediately rises quickly. It waited until 201F engine coolant to open, but then dropped quickly, stabilized at ~193, and continued to rise very slowly.

The level in the expansion tank went up about 1" by the end of the test. Little to no level rise would indicate there is air trapped in the system -- which normally is only present after a refill.

Just idling @ 40F ambient, it took longer (56 minutes) than I would have guessed to get to the thermostat open. In the usual startup and drive situation, it's >190 quickly.

Good luck,

Rednroll

When I initially started diagnosing, I did notice the hose of the inlet was hotter than the return. I used a laser thermometer to measure those temps. This is what caused me to flush the heater core. I really didn't notice any dirt or other foreign material come out and I reversed flushed it and forward flushed it multiple times using water and an air compressor. After flushing the heater core, I topped off with coolant, raised the front end and burped the system to get rid of any air. Immediately, after completing this, I took it for a drive and the heat was working great for about 15-30minutes. Then it gradually got cooler and cooler. So I am therefore suspecting a small leak although it isn't a leak where I notice coolant dripping. It seems to be the only thing that makes sense that the heat would be working and then gradually get cooler and cooler the more I drove.

I took the top shroud off today and inspected the sides of the radiator. There's not much that can be seen. I have a 2009 and there seems to be a different radiator than what was previously posted where if I look on the sides of my radiator, I just see the plastic end tanks that mount onto the sides of the radiator core.

I also noticed my overflow after 2-3 weeks after the top off and burbing is now on the low side but the radiator level was still full. I filled the overflow back up to the max line. So this seems to indicate a small leak somewhere as well. I'll leave the top shroud off so I can continue to visually inspect again and see if I notice any leaks.