Thermostat stuck closed?

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

metalmoto

Full Access Member
Joined
Jun 6, 2015
Messages
153
Reaction score
2
Location
Philadelphia
HELP!
O4' with 167,000 miles on it. Noticed slight water pump leak at weep hole. Replaced it.
A week or two later, found crack in radiator. Replaced it. Also new hoses and plastic reservoir tank.
Kept smelling coolant though heater vents. Suspect heater core has a small leak.
All was fine for about 2 months now, until today.

It's really cold here, about 30 degrees this afternoon.
Started Jeep, let her warm up a little.
Drove off, it's missing, running rough, slight loss of power.
Pulled over, steam coming out from under hood.
Coolant is low in left side of reservoir tank (looking from front) coolant now filled in right side of tank, and pouring out the overflow. Temp gauge normal, right in the middle as normal.

Thinking coolant coming out of overflow is shorting out coil on plug, right below it.

The only thing I didn't replace is the thermostat.
Going to replace it tomorrow.

Wouldn't a bad miss set a trouble code?

I'm lost. Any suggestions?

Thanks
 

LibertyTC

Well-Known Member
Staff member
Moderator
Joined
Oct 24, 2008
Messages
9,178
Reaction score
1,825
Location
B.C. Canada
Lots going on there. Allow system to be cold then only fill to the cold line.
When you replaced the tank does it have a mopar 16 psi cap?
You must be registered for see images attach

With any suspected leak, a pressure test should be completed, repair all leaks.
Air in system not good, and you need to bleed air out from top rad hose (socket hex bit) you can also with small funnel, fill from this location if rad low.
Only use Hoat or zerex G05 and as far as the thermostat, only use a mopar one.
You must be registered for see images attach

Misfiring- remove the effected coil packs, use compressed air to blow coolant out.
Clean and dry coil pack and ensure sealing washer on coil pack is present.
A consistent miss can set a trouble code.
Do you have any bubbles on oil dipstick by chance, or sign of coolant mixing with oil?
 

uss2defiant

Full Access Member
Joined
Jun 25, 2014
Messages
3,600
Reaction score
157
Location
Tucson, Arizona
I'd check the reservoir for any leaks too. My factory one finally gave out on me.

Pressure test the cooling system.

You'll need both kits if you're getting the loaner from autozone.
 

metalmoto

Full Access Member
Joined
Jun 6, 2015
Messages
153
Reaction score
2
Location
Philadelphia
OK, Now I'm almost 100% sure it's a faulty reservoir tank.
I have a coolant pressure tester, and just went out to try something. I hooked up the tester, and started the car, thinking, if there is a blown head gasket, the pressure gauge should rise on it's own, without me pumping it up.
It did not. Then I tried pumping it up. I can clearly here a leak somewhere, but don't see any coolant leaking out anywhere.

Also, to keep coolant from spewing onto the spark plug coils and getting down in the holes. I installed a rubber hose into the overflow hole in the back, and routed it down the back of the engine. So it will just go into the ground below.

I was able to get the two back coils off, and blew a lot of water out of the spark plug holes. On the third one, the whole stud came out of the valve cover. But for some reason, I could not get it completely out. Ran out of daylight, so I didn't get to blow out that spark plug hole.
Not sure what was keeping the stud from coming completely out?

The car is still missing. Is it possible, that the coolant damaged one of the coils? Or perhaps a plug is fouled from not firing all the time?

I also used electrical contact cleaner, inside the electrical plugs to the coils, to make sure this wasn't the problem either.

I will order a new tank, but still need to fix the miss.
It seems to be intermittent at times, and goes away when I step on the gas, sometimes. Mostly noticeable at idle.

I have good used coils from my 02' Jeep. I assume these are the same as the 04' model?

I guess I'll try swapping the old coils I have, and see if this fixes the miss. Can't do this until the weekend.

I will keep you informed of my progress.
Thanks very much for your help.

It's too cold outside and dark now, for me to do anymore tonight
 

metalmoto

Full Access Member
Joined
Jun 6, 2015
Messages
153
Reaction score
2
Location
Philadelphia
OK, the used reservoir tank I bought looks awful.
I see 2 small cracks in it, but not sure if this will effect it.
Trying to figure out a way to pressure test it.
I have a coolant pressure tester. Need to plug up the hose connections I guess.

Otherwise, looks like uss2defiant was right about the coils.
The small bottom part, looks glued on, and on 2 of them their loose and spin. Also the top rubber seals were missing.
I found 2 old coils with intact seals, so put them where they got coolant in them before. They probably were lost years ago when the plugs were changed. Not sure where to get new ones, or if it's even possible to replace them...

Took out the plugs on the side under the tank. Center one looked wet, not oil.
Did a compression test on those 3 cylinders, All seemed good 190-200 PSI. Didn't bother with the other side, besides it started raining. Got the plugs back in, and put used good coils back it. A quick start and run for a minute, seems fine, no misfire. Didn't want to run it long without the tank installed.

After work on Friday, I started the Jeep from the passenger side door. Then walked back to look at the exhaust smoke.
Got some white smoke for a few seconds, then it stopped.
So, there might be a slight head gasket leak, not sure.

Waiting for a combustion leak tester to come in the mail.
Otherwise, just want to get the missing fixed.

Trying to get the Jeep to last through the winter. Need 4WD to get to work in the snow. My work never closes, because of bad weather. I have to drive 12 miles of winding rural 2 lane roads.
Was really impressed last year, when we got a foot of snow on the un-plowed roads. Every other car was stuck on the hills. My Jeep had no problem, went around so many stuck cars. And 2 school buses sideways completely blocking the road. I narrowly got past a stuck school bus, blocking the road, while everyone else was stuck. I was very pleased with both my Jeeps, getting me through deep snow, on two different occasions a year apart. I am hooked, and now I know why my work parking lot is filled with Jeeps of all kinds. Must of counted at least 10 Liberty's in the lot.
Plus many other models. It a huge company, 850 employees. 3 shifts, operating 24/7. In rural Pennsylvania.
Also encountered flooded roads often. Can't see the road is flooded late at night when I get off. Jeep hits the water going 40MPH. Water covers the windshield, can't see a thing, but never lost control, goes straight. never stalled. It has saved me countless times! I can't say enough...
Someday I will put my dash cam vids on YouTube to share my experiences, driving through deep snow and flooded roads. It's amazing, and wish I bought a Jeep years ago.
Thank you all for your help with my problems, you guys are are great!
 

metalmoto

Full Access Member
Joined
Jun 6, 2015
Messages
153
Reaction score
2
Location
Philadelphia
OK, the used reservoir tank I bought looks awful.
I see 2 small cracks in it, but not sure if this will effect it.
Trying to figure out a way to pressure test it.
I have a coolant pressure tester. Need to plug up the hose connections I guess.

Otherwise, looks like uss2defiant was right about the coils.
The small bottom part, looks glued on, and on 2 of them their loose and spin. Also the top rubber seals were missing.
I found 2 old coils with intact seals, so put them where they got coolant in them before. They probably were lost years ago when the plugs were changed. Not sure where to get new ones, or if it's even possible to replace them...

Took out the plugs on the side under the tank. Center one looked wet, not oil.
Did a compression test on those 3 cylinders, All seemed good 190-200 PSI. Didn't bother with the other side, besides it started raining. Got the plugs back in, and put used good coils back it. A quick start and run for a minute, seems fine, no misfire. Didn't want to run it long without the tank installed.

After work on Friday, I started the Jeep from the passenger side door. Then walked back to look at the exhaust smoke.
Got some white smoke for a few seconds, then it stopped.
So, there might be a slight head gasket leak, not sure.

Waiting for a combustion leak tester to come in the mail.
Otherwise, just want to get the missing fixed.

Trying to get the Jeep to last through the winter. Need 4WD to get to work in the snow. My work never closes, because of bad weather. I have to drive 12 miles of winding rural 2 lane roads.
Was really impressed last year, when we got a foot of snow on the un-plowed roads. Every other car was stuck on the hills. My Jeep had no problem, went around so many stuck cars. And 2 school buses sideways completely blocking the road. I narrowly got past a stuck school bus, blocking the road, while everyone else was stuck. I was very pleased with both my Jeeps, getting me through deep snow, on two different occasions a year apart. I am hooked, and now I know why my work parking lot is filled with Jeeps of all kinds. Must of counted at least 10 Liberty's in the lot.
Plus many other models. It a huge company, 850 employees. 3 shifts, operating 24/7. In rural Pennsylvania.
Also encountered flooded roads often. Can't see the road is flooded late at night when I get off. Jeep hits the water going 40MPH. Water covers the windshield, can't see a thing, but never lost control, goes straight. never stalled. It has saved me countless times! I can't say enough...
Someday I will put my dash cam vids on YouTube to share my experiences, driving through deep snow and flooded roads. It's amazing, and wish I bought a Jeep years ago.
Thank you all for your help with my problems, you guys are are great!
 

uss2defiant

Full Access Member
Joined
Jun 25, 2014
Messages
3,600
Reaction score
157
Location
Tucson, Arizona
I got my replacement tank and coils from autozone. all have lifetime warranty.
No choice since I had to get my jeep going the same day.
The tank is a dorman so the nipple of the tube to the overflow, non pressurized side, points to the front instead to the side like the OEM.

I've tried looking for those boot covers before too and I wasn't able to fine replacements.
 
Top