Cooling issues, Meltdown temp then back to normal

xhizzous · **Posted:** Sun Feb 14, 2016 11:41 am

05 CRD in my signature is having issues. I put a brand new HDS Thermostat in it about 2 weeks ago and filled the system back up with mopar coolant/Distilled water.

In that 2 weeks I have done normal every day driving, at least 1 hour per day as well as a 3 hour each way to PA and back and had no problems with the vehicle.

Saturday 2/13 after driving about 30 minutes the jeep heated up to max according to the temp gauge and I had to pull over, It seems to be running perfectly fine otherwise. I let it sit in a parking lot for about 2 hours then made a 10 minute trip with it during which the temp acted fine. parked for another 2 hours and started driving again. Within 10 min the temp gauge was at 3/4 and climbed to max. Pulled over and let it idle and temp dropped to middle of the gauge again no problem. It drove about 25 minutes home after showing normal temp .. if i exceeded 2k RPM the temp would climb rapidly until the chime started but if I dropped the load on engine to ~2k or lower temp would drop to normal.

I have parked it for now until I can figure this out but I need to get it back in service as soon as I can.
I have a normally slow mystery coolant leak that I still cannot find, I believe this problem is probably related but I cant figure out why the cooling system will hold pressure for more than 24 hours if left sitting. How/where would it be leaking out if it still holds pressure that well? The coolant consumption tends to increase when the weather gets very very cold for some reason.

I have tried to bleed air out of the system by filling the recovery tank and cracking the vent on top of the radiator and letting the radiator fill. I keep thinking that mabye this cooling problem is caused by an air bubble in the upper radiator hose/thermostat assembly. This is how I normally bleed air out every time I add more coolant If I see it getting low.

Do you guys have anything I can check to mabye determine how the coolant is escaping / any ideas what would cause it to go to meltdown temperature?

olypopper · **Posted:** Sun Feb 14, 2016 11:50 am

When you filled the coolant system, did you open the bleeder on the passenger side, top corner of the radiator? Have you verified the engine is actually overheating? A digital temp gun can be used to take temps at the thermostat top for reference. Another possibility would be a sticking thermostat and that would be a quick and easy swap.

As for your mystery coolant leak, a pressure test like many have described on this site would be a good starting point. Pull the glow plugs and pressurize the cooling system to see if there is any coolant going into the combustion chambers.

xhizzous · **Posted:** Sun Feb 14, 2016 11:58 am

I have not verified with a separate sensor that the engine is actually overheating.

I thought of the Sticking thermostat scenario as well, is there any reason it would fail/stick that quickly? Its been installed for almost exactly 2 weeks.

Yes, I always pop the bleeder in the radiator to let the radiator fill all the way up when I have the cooling system open. That is the normal fill method I use as described in the original Post.

I will probably have to take it somewhere to get a test done on it. I would like to this its not the headgaset as It has APP studs that were installed for the previous owner by geordi back when it had the timing belt done.

If it was head gasket why would it hold pressure so well after sitting for over a day or 2?

olypopper · **Posted:** Sun Feb 14, 2016 12:42 pm

It may not be a head gasket but could be half dozen other things. Some leaks don't show until running when thermal expansion happens. Start with the easy stuff first though, like the thermostat.

Hexus · **Posted:** Sun Feb 14, 2016 1:08 pm

I've seen brand new, just out of the box, parts fail immediately.

To say something failed in 2 weeks is totally believable.

flman · **Posted:** Sun Feb 14, 2016 1:16 pm

Sounds like a HG leak, I recall mine would do all kinds of weird spikes and drops in the temperature that did not even make sense according to the load on the engine. When combustion gas was going passed the temp sensor instead of coolant, the sensor would drop in temp, while the engine is actually overheating more.

Are you loosing fluid through the weep hole at the back on the recovery bottle? Is your cooling system still pressurized after you allow it to cool down overnight? Are you loosing cabin heat under heavy acceleration?

xhizzous · **Posted:** Sun Feb 14, 2016 1:27 pm

flman wrote:

Sounds like a HG leak, I recall mine would do all kinds of weird spikes and drops in the temperature that did not even make sense according to the load on the engine. When combustion gas was going passed the temp sensor instead of coolant, the sensor would drop in temp, while the engine is actually overheating more.

Are you loosing fluid through the weep hole at the back on the recovery bottle? Is your cooling system still pressurized after you allow it to cool down overnight? Are you loosing cabin heat under heavy acceleration?

Its never got hot before like this. its had the mystery leak for the better part of a year at least. I am for sure loosing stuff through the weep hole at the back of the recovery bottle. It blasts pressure into the insulation on the firewall, although I usually don't see it forcing liquid out.

The cooling system will remain pressurized even after sitting for 2 days without being turned on. I have not noticed it loosing cabin heat under acceleration or any other activity.

I'll pop a new thermostat in it I guess, at least that is easy with the redesigned thermostat housing.

flash7210 · **Posted:** Sun Feb 14, 2016 1:30 pm

Quote:

If it was head gasket why would it hold pressure so well after sitting for over a day or 2?

Quote:

am for sure loosing stuff through the weep hole at the back of the recovery bottle. It blasts pressure into the insulation on the firewall, although I usually don't see it forcing liquid out.

These are bad signs.
The cooling system should not be retaining any pressure after it has cooled down.
I suspect a head gasket problem.

xhizzous · **Posted:** Sun Feb 14, 2016 1:49 pm

If it is head gasket that is going to be very bad news......Still owe a bunch of money on it currently :/

I have done the timing belt job on my 06 and I do currently own the full miller tool set 3 cases + some other stuff, but I'm still a bit apprehensive about tearing that far into this.

Maybe I need to talk to our resident VM diesel expert and see how much it would cost to have him pay me a visit. If I currently have ARP head studs installed will they be reused, or do I have to purchase a full new set for head reinstall?

If the EGR Cooler was leaking would it cause pressure to enter the cooling system/ coolant loss?

Mountainman · **Posted:** Sun Feb 14, 2016 1:51 pm

Yeah, sure sounds like a head gasket. Running the engine at the proper temp just made the problem obvious is my guess. Thanks Jeff :goink:

I would throw a new thermostat in just in case though. Not unheard of for there to be a burr or other imperfection on the shaft of a new thermostat. A bad thermostat could have just made short work of blowing an already weeping HG :2cents:

Mountainman · **Posted:** Sun Feb 14, 2016 1:52 pm

xhizzous wrote:

If it is head gasket that is going to be very bad news......Still owe a bunch of money on it currently :/

I have done the timing belt job on my 06 and I do currently own the full miller tool set 3 cases + some other stuff, but I'm still a bit apprehensive about tearing that far into this.

Maybe I need to talk to our resident VM diesel expert and see how much it would cost to have him pay me a visit. If I currently have ARP head studs installed will they be reused, or do I have to purchase a full new set for head reinstall?

I would definitely reuse the ARP's myself.

flash7210 · **Posted:** Sun Feb 14, 2016 2:00 pm

Quote:

or do I have to purchase a full new set for head reinstall?

Nope.
ARP studs are reusable.
Unfortunately any new head gasket you buy will also come with a set of bolts that you will never need.

Once you pull the head, take it to a good machine shop to have it pressure tested for cracks.

xhizzous · **Posted:** Sun Feb 14, 2016 2:06 pm

Can I tell what head gasket I have without tearing engine apart first or will I have to get down to the gasket before I order a new one in?

Mountainman · **Posted:** Sun Feb 14, 2016 4:23 pm

xhizzous wrote:

Can I tell what head gasket I have without tearing engine apart first or will I have to get down to the gasket before I order a new one in?

It's possible, but difficult to tell. Mirror would help, and maybe it won't be too bad if you can get in there and clean it with a rag and some cleaner.

flash7210 · **Posted:** Sun Feb 14, 2016 4:58 pm

xhizzous wrote:

Can I tell what head gasket I have without tearing engine apart first or will I have to get down to the gasket before I order a new one in?

Shine a flashlight below the drivers side of the intake manifold. There is a wide tab sticking out between cylinders 2 and 3.
The 1 hole gasket is most common.

TURBO-DIESEL-FREAK · **Joined:** Sat Apr 17, 2010 3:29 pm **Posts:** 1167

The diagnosis from the posts here seem to be spot on. I would suspect head gasket issues as well; however, xhizzous, contact me if you wish so I can get the details and help any way I can.

Indeed, try another thermostat valve, perhaps a 190 degree valve... that is what the Model 001 is designed for.

Best regards,

xhizzous · **Posted:** Sun Feb 14, 2016 5:46 pm

TURBO-DIESEL-FREAK wrote:

The diagnosis from the posts here seem to be spot on. I would suspect head gasket issues as well; however, xhizzous, contact me if you wish so I can get the details and help any way I can.

Indeed, try another thermostat valve, perhaps a 190 degree valve... that is what the Model 001 is designed for.

Best regards,

yea, I'm thinking its head gasket as well now. There is no reason I should be getting an air bubble inside the top of the radiator/ pressure while the vehicle is cold.

https://www.youtube.com/watch?v=4Go4FC0riQs

that video is not me but what his recovery bottle does is the same thing mine does.

Mountainman · **Posted:** Sun Feb 14, 2016 7:52 pm

wow, yeah, that is definitely a serious HG leak. If you look in the reservoir really close with a light, you will probably see bubbles streaming out while it is running. Cap off, cool-cold engine.

xhizzous · **Posted:** Sun Feb 14, 2016 9:34 pm

dang..... so much for those ARP studs. I guess what little tax return I got this year is spent and no GDE Tune or intake elbow kit for the 06

I just hope its not a cracked head issue or anything like some of the guys on here have had.

Any recommendations on other mods/ things to replace while I am in the motor this far? oil pump.. vacuum pump? .. Im definitely going to fully delete the EGR setup, I already have the intake elbow on it Next step is to rid it of the cooler.

geordi · **Posted:** Mon Feb 15, 2016 12:26 am

I'm curious about this... This sounds like a huge leak, and on one that I did ARP studs on?

I haven't looked at the video link yet (can't right now but should be able to tomorrow) but have you tried the cold engine test?

With a cold engine, open the cap to release any pressure that may be there. (Holding pressure can be completely normal, and doesn't by itself indicate anything at all)
Cap it back up, and run the engine for about 30 seconds to a minute. Not long enough for any coolant expansion to happen - so open the cap again. Pressure? Then there are two places for that to enter: The EGR cooler or the head gasket.

This is a laminated steel gasket, and unless the gasket was the wrong size originally (could be possible) and the liners are impacting the bottom of the head instead of allowing the gasket to compress... I cannot see where the ARP studs could have failed and you are now having a head gasket issue. I would be concerned about potential cracks in the head that went undiagnosed... But I would also suggest the two-hole gasket to allow for better clamping after the head is inspected for any cracking that could explain this leak. I don't normally lift the head when doing the ARP studs, so whatever was there before is retained, just compressed stronger. This has been successful on more than 20 CRDs thus far, so I am very curious what is happening in your case.

Cooling issues, Meltdown temp then back to normal

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