No Cabin Heat on Warm-Up, Coolant Issues, Bad Head Gasket?

fool4wheelin · **Posted:** Mon Apr 02, 2018 1:52 pm

After replacing my head last spring I'm getting concerned with some recent strange behavior from my CRD:

- No cabin heat when the engine is warming up. As soon as the temp gauge needle points vertical (and the thermostat opens) it blows warm.
- Coolant reservoir tank still pressurized after system cools down. Is also pushing coolant into expansion tank.

I used ARP studs with the replacement head and also removed the EGR system. I was losing some coolant from the union that replaced the Y where the EGR cooler returned, but that seemed to go away after I tightened the hose clamps. After searching the forums I ran across this post:

http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=75340&p=790395&hilit=tale#p790395

I'm concerned I'm getting trapped air in my head and am now dealing with another head/head gasket issue. Any chance a malfunctioning thermostat would cause any of my symptoms?

I pressure tested the coolant system and it holds ~16 psi. From here I'm planning on checking my coolant for exhaust gases and will send in an oil sample for analysis.

APC9199 · **Posted:** Mon Apr 02, 2018 2:58 pm

Are you losing coolant? Has the gauge ever gone PAST vertical? It really sounds more like air trapped in the system somewhere. Start the motor and let it run for a minute, then crack the bleeder on the top of the radiator for a minute. I usually squeeze the hose going to the thermostat a few times with the bleeder open to try to force any air in the system to move. Did you flush the cooling system when you redid the head (and did you use a NEW head gasket)? Also, what type of coolant are you using. Sorry for all the questions, but the cooling system on these vehicles has been a topic of huge debate over the years, so we need to eliminate a number of things.

flash7210 · **Posted:** Mon Apr 02, 2018 3:05 pm

In addition to everything APC stated above...

You say you pressure tested at 16psi. How long did it hold for? 30 minutes or more?

If you suspect a head gasket leak, do the pressure test again.
Then remove all 4 glow plugs and unplug all 4 injectors.
Wait about 15 minutes while still under pressure, then crank the engine.
If water shoots out the glow plug holes, then yes, you have a head gasket leak.

What thermostat are you using?
Are you using a in-line thermostat along with the factory thermostat?
If so, get rid of the in-line.

If you are still using the factory original thermostat you should replace it with another Mopar unit.
Don't use Crown or any of the other off-brands.

fool4wheelin · **Posted:** Mon Apr 02, 2018 4:17 pm

APC9199 wrote:

Are you losing coolant? - Hard to tell with the leaky union barb and coolant blowing into expansion tank. Oil level isn't going up and oil looks fine.
Has the gauge ever gone PAST vertical? - Not that I know of
Did you flush the cooling system when you redid the head (and did you use a NEW head gasket)? - Did not flush cooling system, was waiting to make sure everything was working first. Had it previously flushed in 2012 when I bought it. Yes to new head gasket. Used Permatex Copper Spray on both sides of gasket, not sure if this was good or bad
Also, what type of coolant are you using. - Zerex G-05

flash7210 wrote:

You say you pressure tested at 16psi. How long did it hold for? 30 minutes or more? - Only held it for a few minutes. Will have to borrow tester from O'Reily again.
What thermostat are you using? - OEM, Was replaced in 2012 with TB Job. Still have original on the shelf.
Are you using a in-line thermostat along with the factory thermostat? - No

papaindigo · **Posted:** Mon Apr 02, 2018 4:40 pm

before you get engine fully warmed up are both heater core hoses equally hot?

fool4wheelin · **Posted:** Mon Apr 02, 2018 11:31 pm

papaindigo wrote:

before you get engine fully warmed up are both heater core hoses equally hot?

I checked this on my way home from work today and it felt like both hoses were warm, the one coming off the viscous heater was maybe a little warmer?? Strange because it was still blowing cold air in the cabin. It was ~25°F outside today. Also strange in that I was getting some warm air out of the vents after starting it and letting it idle for a few minutes, but as soon as I drove away (and VH heater turned off from higher RPM's?) it would get cold. Temp gauge also seemd to move around between 1 and 2 ticks below vertical after it warmed up. Maybe I have a bad thermostat and a plugged heater core?

I took an oil sample tonight and sent it in to the lab, will take a couple weeks before I hear back on that. I also went and checked-out the cooling system pressure tester again, I hooked it with a warm engine and pumped it up to ~16 psi. It only dropped ~2 psi over 30 min, which could partially be from the engine cooling down. Will try to check it again with a cold engine.

I've had a full coolant expansion tank for a few months (?) now so over the weekend I vented the pressure cap with a hot engine and let all the pressure out and then twisted the cap back on. It did fully draw all of the coolant from the expansion tank back into the reservoir that night, but purged it all back into the expansion tank on my way to work this morning.

This Jeep is my daily driver, so I will continue to drive it during troubleshooting unless there is a reason I should park it. I can park it, would just need to get my XJ out of storage.

GordnadoCRD · **Posted:** Tue Apr 03, 2018 3:31 am

It might help, when bleeding air out of the top radiator vent, to have the vehicle parked with the nose high. A few inches higher than the rear can help the air bubbles move to the front.

I just went ahead and installed a flushing T in my heater hose. https://www.summitracing.com/parts/rnb-47153?seid=srese1&cm_mmc=pla-google-_-shopping-_-srese1-_-dorman&gclid=Cj0KCQjwzIzWBRDnARIsAAkc8hFh59bwTsIoaNvPk21LJvOhgukYQLhV6zE3yDojEMILDQbuqLe9woAaAiH4EALw_wcB
Other than the tank, it's the highest point in the circulating coolant system, so easy to bleed.

With the significant possibllity of air bubbles being trapped, If they are in the heater core, it's not such a big deal, but if you get air bubbles trapped within the cooling jacket of the engine, it really can be, and quickly. Air allows the bit of engine adjacent to rapidly heat up, and turn the local coolant into steam, causing it to expand (1500x in volume) making the air pocket bigger, making a chain reaction loop where the engine gets hot enough to cause failure of head, cylinder liner, or whatever the affected area is.

fool4wheelin · **Posted:** Tue Apr 03, 2018 10:57 am

I did find an external coolant leak from holding the pressure test longer on a cold engine, was dripping from somewhere on the water pump intake elbow, will have to do some disassembly to find out where exactly.

Also checked the pressure when the engine was warming up. After 5 min of idling and slow driving it was already up to 10 psi, didn't want to go much higher in case the test adapter didn't relieve at 16 psi.

flash7210 · **Posted:** Tue Apr 03, 2018 12:58 pm

fool4wheelin wrote:

After 5 min of idling and slow driving it was already up to 10 psi,

Ok, so what was the coolant temperature when it was at that pressure?

papaindigo · **Posted:** Tue Apr 03, 2018 1:32 pm

Suggestions
1. replace coolant tank cap with a new one of the appropriate psi rating
2. I presume when you did the head you reused the OEM hose spring clamps. Big no no as they are one use wonders and reuse is at your own risk. Replace with ideally T bolt clamps or at least stainless steel worm clamps.
3. what torque (inner vs outer row) did you use on the ARP studs?
4. I gather you have a new OEM tstat. Where does the dash temp gauge needle sit when engine is at operating temp?
5. NOTE there is no valve in heater lines. Heat vs no heat is set by blend door. If both heater core lines are warm/hot and there is only cold air out of heater core the blend door motor is likely bad.
6. redo pressure test when 1 and 2 done.

At the risk of getting flamed I have never seen or reliably heard of air being trapped in a coolant system with a recovery bottle not since they first came out in the 1960's. The exception is if the coolant is so low in the recovery bottle that air is being sucked back into the system or possibly if the radiator (on CRD coolant tank) cap is bad. These systems are self venting. As hot coolant expands excess coolant and air are forced into the recovery bottle and as the coolant cools off only coolant is sucked back into the system. Given 2-4 cold to hot and back drive cycles all air should be purged from the system.

fool4wheelin · **Posted:** Tue Apr 03, 2018 5:11 pm

flash7210 wrote:

fool4wheelin wrote:

After 5 min of idling and slow driving it was already up to 10 psi,

Ok, so what was the coolant temperature when it was at that pressure? - Sorry, gauge was at ~25%, or halfway to vertical if that makes sense. Hadn't fully warmed up yet.

papaindigo wrote:

Suggestions
1. replace coolant tank cap with a new one of the appropriate psi rating - Aren't all our CRD's 16 psi?
2. I presume when you did the head you reused the OEM hose spring clamps. Big no no as they are one use wonders and reuse is at your own risk. Replace with ideally T bolt clamps or at least stainless steel worm clamps. - Yes I did, will look into replacements.
3. what torque (inner vs outer row) did you use on the ARP studs? - I used whatever was recommended on this forum, will have to go back and check.
4. I gather you have a new OEM tstat. Where does the dash temp gauge needle sit when engine is at operating temp? - I installed a new OEM style in 2012, which is still installed. Temp needle sits 1-2 ticks below vertical.
5. NOTE there is no valve in heater lines. Heat vs no heat is set by blend door. If both heater core lines are warm/hot and there is only cold air out of heater core the blend door motor is likely bad. - The cold air seems to follow the temp needle, but I will continue to monitor.
6. redo pressure test when 1 and 2 done. - The pressure tester goes on place of the tank cap, or is there another type of tester out there?

Currently any coolant in the expansion tank stays there unless I relieve the pressure of a hot engine by opening & closing the cap, then it will suck it back into the reservoir as the engine cools down.

papaindigo · **Posted:** Tue Apr 03, 2018 6:47 pm

fool4wheelin wrote:

flash7210 wrote:

fool4wheelin wrote:

After 5 min of idling and slow driving it was already up to 10 psi,

Ok, so what was the coolant temperature when it was at that pressure? - Sorry, gauge was at ~25%, or halfway to vertical if that makes sense. Hadn't fully warmed up yet.

papaindigo wrote:

Suggestions
1. replace coolant tank cap with a new one of the appropriate psi rating - Aren't all our CRD's 16 psi?
I think so but check FSM
2. I presume when you did the head you reused the OEM hose spring clamps. Big no no as they are one use wonders and reuse is at your own risk. Replace with ideally T bolt clamps or at least stainless steel worm clamps. - Yes I did, will look into replacements. reused OEM spring clamps are prone to causing leaks.
3. what torque (inner vs outer row) did you use on the ARP studs? - I used whatever was recommended on this forum, will have to go back and check.
4. I gather you have a new OEM tstat. Where does the dash temp gauge needle sit when engine is at operating temp? - I installed a new OEM style in 2012, which is still installed. Temp needle sits 1-2 ticks below vertical.
tstat is bad; correct position is ca. 1/2 needle width left of dead vertical; 1-2 ticks is way low
5. NOTE there is no valve in heater lines. Heat vs no heat is set by blend door. If both heater core lines are warm/hot and there is only cold air out of heater core the blend door motor is likely bad. - The cold air seems to follow the temp needle, but I will continue to monitor.
6. redo pressure test when 1 and 2 done. - The pressure tester goes on place of the tank cap, or is there another type of tester out there?

then redo after # 2 is done
Currently any coolant in the expansion tank stays there unless I relieve the pressure of a hot engine by opening & closing the cap, then it will suck it back into the reservoir as the engine cools down.

this is very odd if I am reading you correctly. Coolant should suck back out of overflow tank as engine cools down. I'm not positive but sounds like cap is not staying open properly when under pressure to allow coolant to flow back into tank.

joe_ · **Posted:** Tue Apr 03, 2018 9:18 pm

papaindigo wrote:

2. I presume when you did the head you reused the OEM hose spring clamps. Big no no as they are one use wonders and reuse is at your own risk. Replace with ideally T bolt clamps or at least stainless steel worm clamps.

fool4wheelin wrote:

Yes I did, will look into replacements.

If you go with T-bolt clamps, the ones I found to work were:
2x Gates 32752
1x Gates 32754
1x Gates 32755
That will do both ends of the upper and lower radiator hoses.

GordnadoCRD · **Posted:** Wed Apr 04, 2018 12:18 am

I wish someone would make a coolant cap for these witha built in pressure gauge on top.

fool4wheelin · **Posted:** Wed Apr 04, 2018 8:13 am

papaindigo wrote:

this is very odd if I am reading you correctly. Coolant should suck back out of overflow tank as engine cools down. I'm not positive but sounds like cap is not staying open properly when under pressure to allow coolant to flow back into tank.

This is a pretty good example of what mine is doing: https://www.youtube.com/watch?v=4Go4FC0riQs

After the engine cools down I still have pressure in the system. I can, however, get the coolant in the expansion side to draw back into the reservoir if I relieve the pressure of a hot engine before letting it cool down, this tells me my cap is fine.

Other than a head/head gasket issue what else can pressurize the coolant system like this?

flash7210 · **Posted:** Wed Apr 04, 2018 8:46 am

I'd still replace the radiator cap. Its cheap.
The spring in the cap could be weak and venting pressure too early.

If it were a leaking head gasket, water would be getting into the cylinders.
Symptoms could include water leaking down into the engine oil and water being pushed out through the exhaust. If its going out the exhaust, you would notice white smoke/vapor especially when cold.

As I already mentioned above:
Pressurize the cooling system, wait about 20 minutes.
Remove all 4 glow plugs and unplug all 4 injectors.
Crank the engine.
Watch for water shooting out the glow plug holes.

Edit:
another easy test you can do is replace the narrow hose that goes from the top of the thermostat housing to the top of the coolant tank with clear tubing. Then watch for bubbles wile the engine is fully warmed up and running.

fool4wheelin · **Posted:** Thu Apr 05, 2018 12:03 am

I think I figured out the pressurized reservoir thing, or at least part of it. When I park outside at work, its still cold out (10-20°F) and the engine cools down enough to draw a vacuum to suck the coolant from the expansion tank back into the reservoir. When I park in my ~50°F garage it doesn't get cold enough to draw a vacuum. I'll keep checking this, but I'm thinking it should still be drawing a vacuum even at warmer ambient temps.

I pressure tested my reservoir cap and it is relieving properly. I'm not opposed to getting a new one, I just don't think my symptoms are pointing to the cap right now.

I did go buy some 3/8" clear plastic tubing to check for bubbles in the air bleed line going to the reservoir. I was definetally getting some bubbles, how much is allowed? None?

I'm very curious on the results of my oil sample. Until I hear back on that I'm considering checking for exhaust gas in my coolant. I'm pry due for a coolant flush, new thermostat & reservoir cap, just wast to make sure my head gasket is good before doing those things. I can also pull the glow plugs to check for coolant in the combustion chambers, but that would be a weekend project.

fool4wheelin · **Posted:** Thu Apr 05, 2018 10:18 pm

Here is a video of my “clear tube” test on the air bleed line: http://www.youtube.com/watch?v=EUrV3CE5Omc

flash7210 · **Posted:** Fri Apr 06, 2018 1:11 pm

Its hard to say exactly how much bubbling is acceptable.
Assuming that all the air is bled out of the cooling system, there should be no bubbles.
Is your EGR cooler still connected? I think you've already stated that you removed the EGR.

Proceed with the pressure test and glow plug removal. That will be definitive.

geordi · **Posted:** Fri Apr 06, 2018 4:44 pm

When you replaced the head - What head gasket size did you use? There are three sizes, no-hole, one-hole, and two-hole. The thickest option is the two-hole and is the generally suggested option for any replacement, no matter what the CRD had before.

No Cabin Heat on Warm-Up, Coolant Issues, Bad Head Gasket?

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