Mystery coolant leak

xhizzous · **Posted:** Mon Oct 26, 2015 2:13 pm

I have purchased an 05CRD around 6 or 7 months ago it has about 116k on it now. Timing belt job/ARP headstuds were installed around 85k by geordi before I owned it.

I usually have to put coolant in about 1x per week, sometimes it will go 2 weeks or more without the low coolant light coming on. temp stays at 1/2 when it gets heated up so it wouldn't seem to be overheating. Coolant seems to be under pressure even when its sitting cold.

I have never run it out of coolant, I'm just worried about airspace in the cooling system if its coming out somewhere. Any suggestions on where it might be at? I was thinking possible Heater core but it does not fog the windshield really, especially with it getting cold and running the heater I would expect it to really be fogging the windshield now.

I have read all the way through
viewtopic.php?f=5&t=61065&start=20

flash7210 · **Posted:** Mon Oct 26, 2015 2:35 pm

Every rubber hose connection and clamp is a potential leak point. I had to replace several factory spring clamps because they lost tension and were leaking.
I used a cooling system pressure tester to pump up the coolant tank to 16 psi. Then I walked away and came back about 30 min later to check the pressure. If the pressure dropped then there was a leak somewhere. I then checked for puddles and felt around every hose connection to find the leak.

lacabrera · **Posted:** Mon Oct 26, 2015 2:58 pm

I need to tread carefully but you may have a head gasket/ cracked head problem I hope I am wrong? and its just leaking some were else.

flash7210 · **Posted:** Mon Oct 26, 2015 3:02 pm

If you find that all your hoses and clamps are not leaking then that leaves 3 possibilies:

1. Head gasket leak.
Since you have already had ARP studs put in this should not be the case. But its certainly not impossible.

2. EGR cooler leak.
Even if you have disabled your EGR valve, if the coolant lines are still attached to the EGR cooler its a potential leak point.

3. Cracked head.
Hopefully this is not the case but its what happened to me. My engine was dumping coolant out the exhaust. I thought it was a head gasket leak but turned out to be a cracked head.

papaindigo · **Posted:** Mon Oct 26, 2015 3:33 pm

If you are adding coolant then you have a leak somewhere. As flash notes every single hose, hose clamp, etc is a potential leak point and if a couple of them are leaking even a little bit such that the drip hits a hot surface you could lose a fair amount of coolant and not see anything. I'd get some coolant system UV dye and a UV flashlight (Amazon under $20), add dye to system, drive for several days, find shady/darkish spot and look for leak with UV flashlight. Don't forget radiator, water pump leak out of bottom of timing belt cover, EGR cooler and hoses, oil cooler and hoses, heater core (check drip tube on firewall under coolant tank), pinhole in coolant tank, etc.

Quick head gasket check. On cold engine pop coolant tank cap; replace; crank up and run for say 15 seconds; shut down, remove cap; is there pressure=bad is there no pressure=good.

Consider new coolant tank cap as weak pressure relief spring can cause coolant overflow and loss.

Mountainman · **Posted:** Mon Oct 26, 2015 4:44 pm

Besides all of the above, I have noticed one engine that left a white mineral looking stain at the block heater (remnants of a slow leak), and the same stains on the bottom of the hoses that connect on the manifold that attach to the water pump. Not sure if it's possible to see these with everything assembled, but you might crawl underneath and or try a mirror to see the bottom of every leak point.

I had one that I thought was a head gasket, but it turned out to be one of the hoses leaking very slowly. It left a stain but would dry so fast that I had to get my hand in there when I had been running it up a long hill to find the seep (it was wet). I got a couple of small burn blisters but found the darn leak. UV probably a lot better option as everything in there gets mighty hot lol...

lars0247 · **Joined:** Sat Oct 12, 2013 12:09 am **Posts:** 98

1. Put in some UV Dye.

2. Drive it around for a few days, look for traces of UV dye.

3. If you still don't find a leak, pressurize the system to about 12 psig using a proper regulator and t-fitting between the radiator and hose that goes back to the coolant bottle.

4. Pull your glow plugs

5. Let sit for a few hours or overnight.

6. Attempt to crank engine, keep everyone away from the glow plug holes because if there is a head gasket leak or cracked head, the coolant will blast out of the open glow plug holes with amazing force.

This is how I found my leak, which after pulling the head and having it pressure checked by a competent cylinder head shop, turned out to be cracks behind the intake valve pockets on the #3 and #4 cylinders.

A low mileage "test-engine" head with ARP studs fixed my issue.

Chasleon · **Joined:** Fri Oct 30, 2015 4:39 pm **Posts:** 8

I have had a leak to randomly occur, that would get the shield covering the exhaust manifold with coolant and cause steam. That made the interior of the jeep stink like anti-freeze. I pulled the reservoir tank to check and replace all of the short hoses (and there are a dozen or so). While I had the tank off of the vehicle, I went to set it aside and noticed that at the rear top of the tank, there is a vent/weep hole. This is where the coolant proved to be leaking from and getting the top of the exhaust/passenger area wet.
I drilled the hole out with a 7/32 bit and pushed a 1/4" 90 deg brass hose barb into it, and ran a hose down to below the engine compartment.
I am still dealing with a coolant loss issue, but at least it's not steaming up and stinking the interior up.

I bought a technician's training manual to get a routing diagram of the large collection of coolant hoses, to verify that none had accidently been reconnected in the wrong position. I am the second owner and previously allowed a dealership to work on my CRD. That was a mistake. Anyway, I took my fine diagram out to run it all down... and I have more hoses on the engine than the diagram indicates.

Now I am hoping to find another CRD in the area to compare with what I have.

Brasher · **Joined:** Sat Mar 14, 2015 7:02 pm **Posts:** 80

The weep hole is on the overflow side of the reservoir. If you are getting coolant in there and haven't been towing a trailer up a mountain or just overfilled the coolant system, that's bad news.

weeks101 · **Joined:** Mon Jul 30, 2012 3:29 pm **Posts:** 747

flash7210 wrote:

2. EGR cooler leak.
Even if you have disabled your EGR valve, if the coolant lines are still attached to the EGR cooler its a potential leak point.

xhizzous, is your EGR system stock? Like flash suggested, it's not uncommon for the EGR cooler to leak "internally" into the EGR valve. This if often overlooked and diagnosed as a failed head gasket. If your EGR set-up is stock, remove the lower EGR tube (labelled intake side in the image below) from the EGR valve. You just need to remove the two bolts from the flange and pivot it outwards, no need to remove the v-band connection at the intake elbow (just loosen it). If coolant comes out, you'll need a new EGR cooler ($$$) or you can delete the system entirely (see my sig for our offering).

This diagram might help you visualize what I am describing:

Cheers,
Seth

thefunk · **Posted:** Wed Dec 16, 2015 11:29 am

Harbor Freight sells a rad test kit for 90 bucks. Not real cheap, but cheaper than anywhere else, and makes troubleshooting cooling system leaks about 1000% easier.

If it's the heater core, you'd smell it. If it's an external engine leak, you'll smell it. If you're having to add coolant that often it's a pretty sizable leak; you should be able to smell coolant burning off the engine if its external. If so, pressurize it and start crawling all over the engine looking for a drip or moisture. I've also seen radiators start leaking from the tank/core seam and defy detection for months because the coolant evaporated off (with no odor) as fast as it leaked out. Finally the seam blows out and it gets much easier to spot. It's especially hard to spot leaks on the front of the radiator because they stack the condensor in front of the radiator.

An old motorcycle trick for spotting very slow leaks is to spray the connection with athlete's foot powder spray. It dries within seconds, if you have even a very slow leak it becomes obvious very quickly. Also cures the engine of any fungus problems.

flash7210 · **Posted:** Wed Dec 16, 2015 1:40 pm

thefunk wrote:

Also cures the engine of any fungus problems.

Finally, a solution to my fungus problem

Chasleon · **Joined:** Fri Oct 30, 2015 4:39 pm **Posts:** 8

I have a brand new radiator, water pump, thermostat and all new hoses. The coolant system builds pressure while driving and after it's parked will hold that pressure for weeks at a time. It doesn't over heat and the heater gets warm.
I have GDE programmer and have been driving the jeep for two years with no obvious reason as to why the coolant indicator light comes on.
I have been having to add about a half gallon of anti-freeze about every 1000 miles.
My last guess is in the hose routing. But if I knew everything, I wouldn't be talking about my problem.
I have about 180K miles and meticulously monitor everything from routine to just looking when I have the time.
I just replaced the passenger side motor mount and took the last two days looking with bright light under, over and in every hole in the engine compartment.
There just isn't any sign of stain or wet, to suggest where the loss is occurring.
Tomorrow, I will disconnect the lower EGR tube and see if that is where the loss is occurring. I would be perfectly happy to remove the EGR system completely. I don't live in an area where inspections are mandated. So, No problem. I'll report the results..

amslube · **Posted:** Thu Dec 17, 2015 9:56 am

Let me add to flashes list:
#4. Cracked engine block.

I went through a coolant leak earlier this year that just got progressively worse. It started losing about a pint in two weeks or about 400 miles to almost a quart every 50 miles. What made it a bit more difficult to locate was it would not leak on the garage floor and even a pressure tester would hold 15psi for 30 minutes. A visual inspection under the CRD did show a coolant leak path at the rear with stains and wetness where the engine and transmission bolt together. Still, went though the easy stuff first, checking hoses and clamps, bypassing EGR cooler, etc. I had no evidence or signs of an internal head gasket breech but went and replaced the head gasket with ARP studs anyway thinking it was an external HG failure. No joy!!! To shorten the story, pulled the engine to discover a block crack which started to the rear of the exhaust manifold and continued around the back of the engine and was heading the intake side of the block.
Apparently the compression from the running engine would open the crack and coolant leaked out. When the engine was off the crack closed up and wouldn't leak on the floor (shortly before I pulled the engine a few drops did show up on the floor). For those of you that have had the engine removed there is a machines surface at the rear of the block where the transmission adapter bolts up. The machining of this surface left a sharp 90 degree cut at the top of the trans adapter and the crack across the back followed this sharp 90 cut all the way across. Hope yours isn't like this but a cracked block didn't even enter my mind either being they are so rare.
Just to note, the CRD was never overheated, frozen, towed heavily, driven hard, and had 118K on the click.

thefunk · **Posted:** Thu Dec 17, 2015 6:23 pm

That would definitely be at the top of "rare failures". Did you have the block welded or just use stop leak to plug it?

Mountainman · **Posted:** Thu Dec 17, 2015 8:24 pm

thefunk wrote:

That would definitely be at the top of "rare failures". Did you have the block welded or just use stop leak to plug it?

We've had about 3 members or so with the wonderful cracked blocks (in the last two years). Not a lot, but still :furious:

I don't think any of them had any luck fixing the cracks. Or maybe there was one?

amslube · **Posted:** Thu Dec 17, 2015 10:10 pm

Tried JB weld. I think it opened up as soon as I started the CRD. Ended up selling the Jeep "as is". Couldn't see putting the time and money into it at this point, just didn't make economical sense. Overall though, the CRD served well for the 8 years we had it. It was my wife's daily driver and never once left her stranded.

Chasleon · **Joined:** Fri Oct 30, 2015 4:39 pm **Posts:** 8

That's good information Amslube, but since my issue has been going in the same manner for about 60k miles, I'm thinking that this would have gotten worse, the way yours did.
I also believe that if the coolant system bled down after a couple weeks of being parked, that there would be some sort of failure, somewhere. Like a crack or leaking hose. But mine does not leak down.
For this reason, I am inclined to believe that it is in the coolant hose routing, or possibly in the EGR system as was suggested by Weeks101.
It's gotten cold on me and I'm going to wait till a warmer day to get here soon, before I attempt to remove the lower EGR tube.

Weeks101, if I remove the entire EGR system, would I only need the stage 2 kit? Or would both kits be necessary?

flash7210 · **Posted:** Fri Dec 18, 2015 12:10 pm

The pressure in the cooling system is due to the thermal expansion of the liquid coolant.
As the stuff gets hot pressure builds.
When it cools off pressure drops.
If your cooling system is retaining pressure even when cold, something is not right.

Mountainman · **Posted:** Fri Dec 18, 2015 1:06 pm

Maybe I missed it, but did you look for tiny bubble? If the system hasn't been drained lately, and you can see tiny bubbles in the coolant tank while it's running, I'd say that the HG is leaking. From looking at several of these closely in my garage, I am just going to do the HG on mine and it has a very slow leak. I really wanted to just throw ARP's at it, but I have an almost new head to throw on it anyhow, so I might as well have a fresh top end. It is 2x the work though, or more. If you remove the lower turbo support, it is much easier though...

Mystery coolant leak

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