Find that coolant leak

Steve777 · **Joined:** Fri Oct 16, 2015 11:31 pm **Posts:** 283

Well one of my 06's has developed a coolant leak. I have been monitoring the coolant level pretty regularly, and it has been rock steady for years. In the last month or so, I've noticed the coolant going down a bit. In some recent tests, it goes down roughly 3/4" in the overflow tank over a 60-70 mile trip (this is measuring before and after when cold).

So what I have done so far to try and find this is check all the the easily reached coolant hose ends to see if any are wet right after driving and look for traces of dried coolant. Nothing, although it is fairly wet and sloppy here so not all that easy to see leaking coolant from all the snow/mud splash. I did once smell a bit of coolant under the hood after a long uphill climb, but have not been able to repeat that. Also did the smell test at the coolant tank at startup to look for pressure, none (sort of doubt it is a HG leak, just put in ARPs and it had a clean oil analysis right before that). No signs of mixing oil/coolant, oil and coolant are clean and oil level isn't going up.

I thought my next steps would be to get some UV dye for the coolant, and see if I can find any traces of the leak that way. And perhaps another oil analysis to see if maybe the HG gave out.

Any other thoughts from the people here? Any places I should check for a coolant leak of this magnitude that may not be obvious?

WWDiesel · **Posted:** Sat Feb 22, 2020 11:30 pm

Are you still running the EGR system with the cooler? If so, it could be the source of your elusive coolant loss. :idea:

iakj11 · **Posted:** Sun Feb 23, 2020 10:49 am

If you haven't already, remove the plastic lower engine shroud. It has insulation material on the upper side that will absorb small coolant leaks and obscure thier source. Your leak doesn't sound small, but most of the coolant could be blowing off while driving, leaving very little to drip on the ground when parked.

Steve777 · **Joined:** Fri Oct 16, 2015 11:31 pm **Posts:** 283

(oddly did not get any notification of the replies, but see them now)

WW, The ERG system is still in place, has to be for me to pass emissions here, but there is a tune and a block off plate so it is non functional. I did look at that side of the engine for signs of coolant at those hoses but nothing obvious. But that is one of the areas where it is quite wet from road splash so not sure I would see coolant in all that mess.

Yeah, taking off the lower insulation panel might help. Certainly will if we ever get to some warmer, drier weather.

Have been driving it, and topping off the coolant as needed. And one thing I've noticed, there does not seem to be much loss when driving around at low speeds on flat terrain. Nor when going down hill on long runs. But after my 10 mile climb uphill back to my place from town that seems to be when most of the coolant loss happens. Not sure if that is because of the higher engine temps or working the engine more or tilting uphill.

flash7210 · **Posted:** Thu Feb 27, 2020 4:35 pm

Pressure test the cooling system.
Pump it up to 16 psi.
Walk away, come back to check 30 minutes later.
Check to see if the pressure dropped any.
Look for drips. Feel for wetness around ALL hose connections.

If you cant find anything obvious you're gonna have to dig deeper :shock:

Been there, did all the above, and it wasn't pretty :5SHOTS:

WWDiesel · **Posted:** Thu Feb 27, 2020 5:21 pm

If the EGR cooler is leaking internally, you will not see evidence of leakage externally.
The coolant will get sucked into the intake and burned and all you will ever see is a drop in coolant tank reservoir level.
You could plug the coolant hoses for the EGR cooler since you have the EGR exhaust blanked off.

Steve777 · **Joined:** Fri Oct 16, 2015 11:31 pm **Posts:** 283

Rented a coolant pressure test kit from autozone yesterday, and tried to use it. It is a Powerbuilt kit, and while it has 22 some cap adapters none fit the CRD. Best I could do was the generic rubber cone that expands; that would hold 5-10# of pressure for a bit but popped out after a few minutes. So not really able to do a conclusive test, but did look underneath after the two short attempts at pressurizing it.

What I saw was no signs of wetness on the engine's driver side. On the passenger side the bottom of the oil cooler appeared wet and there was wetness on the aluminum elbow tube and its rubber hose coming out of the cooler. Given that the top of the overflow tank kept popping out and some coolant shot out with it, I can't be entirely sure that this wetness isn't just from the tank pop offs. Although I did go for a short drive and look again; those same places were still wet and I could smell antifreeze on the right side of the engine.

I think my next step is to find a pressure test kit with the right adapter for our CRDs. Then to dry off the oil cooler area, and pump it up and leave it sit for a while.

I'd like to think that the wetness on the oil cooler (if that's it) is from a leaky hose, but it may not be.

Any other thoughts from anyone?

WWDiesel · **Posted:** Sat Feb 29, 2020 11:50 pm

Get some UV Dye for coolant, add it to your cooling system, drive it around for a while until it is up to normal operating temperature and let everything circulate and mix real well.
Then stop engine and let it set with pressure on system and then inspect engine & all coolant hoses with a UV light to find source of coolant leak.

A/C Pro Engine Coolant UV Dye 8oz
https://www.autozone.com/test-scan-and- ... 835773_0_0

Steve777 · **Joined:** Fri Oct 16, 2015 11:31 pm **Posts:** 283

Well, just about to close the chapter on this problem, and it has an "interesting" conclusion.

Rented a pressure test kit from NAPA, a Mastercraft (IIRC). It had the right adapter for the top of our coolant tanks. Pumped it up to 15# and within a minute or so started hearing and seeing a regular drip, drip, drip. It was coming from the heater hoses where they attached to the steel bracket that bolts to the valve cover. Upon closer look, the hose clamps for these hoses were not in place (spring type not screw) they were slid back a bit as they would be if you were pulling the hoses off. Hmmm, no biggie, put them back in place, pressure tested and all seemed fine. Took it for a ~80 mile test drive and no loss of coolant anymore. At least nothing I could see after the one trip, will be keeping an eye on it.

So here is the "funny" thing about this. I did most likely have those heater hoses disconnected last summer when I pulled the valve cover/intake to check the cams and lifters and add ARPs. It isn't impossible that I would have forgotten putting those clamps back, but here's the kicker. I have been driving the CRD for 8 months since then, and checking coolant levels (along with oil etc) about every week. It wasn't going down until a few weeks ago, right after a visit to the local Jeep dealer. Dealer was doing the rear control arm recall, and of course they did the usual free checkup, where they wanted me to let them find/fix the coolant leak (along with a few other things). Of course I said no thanks and did not have them do anything beyond the recall. However right after this visit I did notice the coolant started going down.

Now this is the same dealer who several years ago, in their free checkup, told me I needed a new front wheel bearing. I checked right after I got home and no play in that bearing, and it has been fine driving on it for 3 years now.

I suppose that I might have forgotten to replace those hose clamps, but it seems unlikely that they would have held pressure just fine for ~8 months and then started leaking just now. I strongly suspect that this dealer moved the clamps while they were "checking" for problems; in the hope that I would pay them to find the leak, which probably would have been the radiator or some other expensive part.

Just curious what others think, am I blaming the dealer unfairly here?

iakj11 · **Posted:** Sun Mar 08, 2020 11:35 am

This is a good reminder - "free checkups" are never really free...

Find that coolant leak

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