Coolant Leak

amslube · **Posted:** Mon Dec 29, 2014 4:12 pm

I have been experiencing a slight coolant leak..looses about a cup of coolant every couple of weeks and leaves a drop or two on the garage floor once in a while. I've done some poking around and I can see a trace of coolant, a yellow/green line on the drivers side in the seam between the engine block and the transmission...sort of follows that seam down, a drop forms behind the oil pan and drips onto the skid plate.
Last week I pulled out the fuel filter housing to take a better look. I couldn't see any leaks from the coolant lines for the EGR cooler or anything else. No "smoking gun" wet drop could be found anywhere. All the hose clamp areas were dry but the two screw type clamps where the hoses connect to the EGR cooler were a bit loose so I tightened them but no coolant dripping. Wiped clean all the dried and damp coolant and cleaned the top side of the skid plate. By the way I also checked all the hose connections on the passenger side and all was dry over there. I ran the Jeep over the weekend and today I got under to take another look. Same trace line as before and a drop or two of coolant under the engine. Pulled the fuel filter housing and again no "smoking gun" or wet leaks visible. I removed the two coolant lines from the EGR cooler and bent a piece of copper tubing to connect the rubber hoses to bypass the EGR cooler. Now to run the Jeep a few more days and check again. If this isn't the solution I may have to get a cooling system pressure tester and take a close look with the system pressurized since it appears nothing leaks when the vehicle is sitting or get a coolant dye.

A secondary issue I had after putting things back together....had a P0183 Coolant temperature circuit high. Code wouldn't clear with my scan tool. Checked the temperature sensor in the 2nd gen. fuel head I installed a year or so ago and it read open, no bent or broken pins. I, for some reason, saved my old fuel head...that sensor read 3.2K ohms and varied with a temperature change. I was able to remove the sensor and transfer it to the fuel filter head in the Jeep and all was well. I guess unplugging this when removing the filter head somehow opened the sensor. FYI- The head of the sensor makes direct contact with the fuel.

papaindigo · **Posted:** Mon Dec 29, 2014 4:37 pm

Probably an EGR related cooler leak. Pressure testing might tell you that there is a leak by showing a pressure loss but it won't do any good determining where the leak is unless you can isolate portions of the system to test one at a time. If the bent tubing test makes the leak go away then given that you have the GDE tune you can just leave the bypass in place as EGR cooling is not needed with a GDE tune. If not I'd recommend a coolant UV dye test to find the leak, probably a hose clamp. Years ago on different vehicle that's about how much I was losing due to a weak hose spring clamp on the lower radiator hose.

amslube · **Posted:** Mon Dec 29, 2014 4:54 pm

I originally suspected a hose clamp but I was over, I believe, all clamps and hoses both visually with a very bright LED flashlight, both topside and underneath, and by feel. There were no wet or even damp spots at clamp areas or any of the hoses. That is why I suspect the EGR cooler. I do have the GDE tune so no issue with the bypass. I'll know more in a few days when I get underneath again for my inspection.

Does anyone know if it is OK to just block off the hoses that go to the EGR cooler? Personally I don't see where it would cause any type of a circulation issue. This question came up on the Cummins forum for the 6.7L. When the EGR cooler was removed from my 2011 I simply blocked off the ports and had no issues.

flman · **Posted:** Mon Dec 29, 2014 5:42 pm

The HOAT leaves a white film when it dries, look for a white film as well as wetness.

amslube · **Posted:** Sat Jan 03, 2015 7:32 pm

EGR bypass didn't stop my coolant leak so today, with a coolant system pressure checker, went at it again. A leak showed up almost immediately but not in the area I was seeing the coolant. I had a leak at a connection on the Meziere inline thermostat housing that was installed several years ago. Tightened the hose clamp to stop the leak. System held 15psi for over 10 minutes with the tester afterwards. Reconnected the EGR cooler lines and rechecked again with no pressure loss. Coolant from the leak was dropping on the serpentine belt. Must be some strange air currents generated by the fan and road speed to get the coolant to where it was showing up. I am going to recheck again in a few days just to insure the leak is gone.

While under the hood today found no play in any direction in the turbo, air box to turbo hose was OK, and changed the air and fuel filters. 115K on the Libby.

amslube · **Posted:** Tue Jan 06, 2015 9:25 pm

Under the Jeep today to see if tightening that hose clamp fixed my coolant leak. Still leaking as I originally posted so back to the drawing board. Removed the fuel filter housing again. Hooked up my coolant system pressure tester and pumped up to 16-17psi and waited. Pressure dropped about 1-2 pounds after about a half hour. Pumped back up to 17psi and waited another 15 minutes or so. Checked all hoses and clamp connections again and all were dry. Even pressurized for that time no drips showed up anywhere!! Put the fuel filter housing back on and with the system still pressurized started the engine and checked again...no drips showing up anywhere. Tomorrow my wife will be putting some miles on the Jeep so as soon as she gets home and the engine is hot I will be under it again. One other thing...once in a while I get the coolant smell, like a drop on something hot. I did see evidence of dried coolant on the EGR tube that comes around the back of the engine to the EGR cooler but for the life of me don't see where that may be coming from.

amslube · **Posted:** Mon Jan 12, 2015 4:03 pm

Back at trying to locate my coolant leak. Yesterday I spent most of the day looking, pressurizing, with no success. Seems it doesn't leak when the engine is cold only when up to temperature, even with 16psi on the coolant system. Anyway yesterday I completely bypassed the EGR cooler...the other day only bypassed the two smaller lines that cool the solenoid. Went for a drive and pulled it into the garage. Didn't get to look at it until this morning but the leak was still there. Wiped up the drops and went for a 15 minute ride. Pulled it right up on the ramps, left the engine running, and climbed underneath. I could see wet coolant running down now both sides of the rear where the engine and transmission join. This time there was also some wet coolant further back on the transmission bell housing. Pulled the starter to try to get a better look also checked inside the housing and was dry. It looks like the leak is at the top rear of the engine possibly an external head gasket leak? Can't see back there and can't reach my big hands far enough down to feel the seam. I don't believe there is anything else back there that can leak coolant. Jeep runs great, no pressure in the coolant reservoir with a 10 sec. morning start so the head gasket is fine otherwise. This thing is kicking my butt!

flman · **Posted:** Mon Jan 12, 2015 5:28 pm

Did you try any dye? Did you try and see if it is leaking around the outer part of the head gasket?

amslube · **Posted:** Mon Jan 12, 2015 5:44 pm

I didn't try dye because I can see the trail of coolant...just gets lost behind the engine where I can't see anyway. It appears to be the outer edge of the head gasket, since that is all that is back there...but again it's almost impossible to see back there. From under the vehicle I can trace the coolant from under the starter up to where I can't see anymore. The Head gasket seam is below the EGR pipe.... maybe if I remove this I can at least feel back there or possibly get a mirror to see once the EGR pipe is removed.

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

If you spray a can of brake cleaner in that area and wipe clean as best you can it might be easier to find the source. The other potential issue other than a leaking head gasket, is a cracked block just above the starter. There may have been a casting issue on a few blocks in the field. We have seen 3 blocks with cracks just above the starter. These were all hairline and had strange behavior as to when the leaking occurred.

amslube · **Posted:** Mon Jan 12, 2015 6:22 pm

The leak is well above the starter, I can see the trail...and runs down both sides of the engine now. That is why I am leaning towards the HG. I had the starter out which made following the trail a bit easier. The rear of the engine and the transmission bell housing is clean so it is quite easy to see the trail of coolant. Just can't see behind the engine where the head gasket is. May try removing the EGR pipe and using some mirrors tomorrow.

flman · **Posted:** Mon Jan 12, 2015 7:28 pm

You can pick up an endoscope on Ebay or Amazon pretty cheap. And it will let you see any where you want on your computer screen.

OTOH, I have heard of a few case of the block casting cracked right on this forum.

amslube · **Posted:** Mon Jan 12, 2015 7:42 pm

GDE mentioned several cases of a spot just above the starter on the block that has been known to crack...my leak originates much higher...but I don't want to even think about a crack!!!!

stynkr · **Posted:** Wed Jan 21, 2015 7:28 pm

I also have a slow coolant leak. But the only 2 symptoms are loss of coolant and the occasional billowing vapor cloud exhaust that smells like the sweet smell of burning coolant. No puddles and no visible leaks in the engine compartment or anywhere else. Don't jump to judge there is a cracked head or failing head gasket. I have had the mechanic say he pressure tested the system over night. He thought he found a loose hose clamp and replaced it.

Here is a history run down:
October 2013 - low coolant light. Topped up.
Spring 2014 - continuation of low coolant light. Topped up. CEL fault on number 2 glow plug. Cleared and kept driving.
August 2014 - completed recommended replacement of serpentine belt, timing belt, water pump, thermostat, belt tensioners and all 4 glow plugs.
September 2014 - returned for a check on the coolant loss issue. Not resolved yet. Continuing to add coolant as needed.

Engine continues to start as it did when new. There is an occasional unusual hick up difference. Fuel economy about the same 23 mpg in city driving

I do not see foamy engine oil or high pressure in the coolant reservoir, neither is there a color change. There is no sign of fluid in the cylinder, IE hydrolocK.

Could I be seeing a EGR cooler malfunction? Does coolant go to the EGR? Do I have a cracked exhaust chamber gallery?

3/15 INSTALLED WEEKS ELBOW KIT to remove EGR system completely. On cold days white smoke stops after engine warm up. Definitely associated with engine temperature.

Is this the end of the world? Or is there a smart CRD with the answer. So far just a lot of whining and no answers.

amslube · **Posted:** Wed Jan 21, 2015 8:35 pm

Now also seeing coolant running down the passenger side of the engine as well as the driver's side. Runs down same as the other side, right at the joint between the engine and transmission. Only see a few drops on the garage floor but losing about a pint every 3-4 days...maybe 150 miles. I put the Jeep up on ramps again today determined to find the source. I removed the heat shield for the crank position sensor. Here is a picture I was able to get with my phone at the rear of the engine. You can see the wet coolant below the EGR crossover tube. Do those 2 holes in the head gasket mean it is a "2 hole" gasket?:

Here is a picture of the drivers side. Looks dry.

Since I have no indication of a breach into a combustion chamber I may try a product recommended to me by a trusted source, BG sealer. I think it is worth a try before I order the HG and studs.

flman · **Posted:** Thu Jan 22, 2015 8:38 am

amslube wrote:

Now also seeing coolant running down the passenger side of the engine as well as the driver's side. Runs down same as the other side, right at the joint between the engine and transmission. Only see a few drops on the garage floor but losing about a pint every 3-4 days...maybe 150 miles. I put the Jeep up on ramps again today determined to find the source. I removed the heat shield for the crank position sensor. Here is a picture I was able to get with my phone at the rear of the engine. You can see the wet coolant below the EGR crossover tube. Do those 2 holes in the head gasket mean it is a "2 hole" gasket?:

Here is a picture of the drivers side. Looks dry.

Since I have no indication of a breach into a combustion chamber I may try a product recommended to me by a trusted source, BG sealer. I think it is worth a try before I order the HG and studs.

Looks like the gasket pic is on the exhaust side? The holes are on the intake side of the gasket. I see the tell tale signs of white dried HOAT on the EGR cross over pipe, as well as that ear on the engine block, and a little on the bell housing, are you sure it is not coming out of the weep hole of the coolant over flow tank? Considering it is getting on the crossover pipe it could make it to the drivers side as well?

flman · **Posted:** Thu Jan 22, 2015 8:50 am

If you look at this pic I took, you can see the cooling journals are near the back of the head. Since there is nothing to leak from above except for the overflow, and the heater hoses, you might want to pull the head? Back of the head is to the left with crossover pipe hanger attached.

amslube · **Posted:** Thu Jan 22, 2015 9:41 am

From what I can tell the left portion of the coolant tank is for expansion and the right side is for overflow?? Nothing in the overflow section.
Yes, there is dried coolant on the EGR crossover pipe as well as the transmission bell housing. Looks like it drips out of the rear of the head and sometimes may spray a bit to get on the bell housing. I most likely will pull the head sometime in the near future and do the job with ARP studs. Since there is no combustion leak, it is not an immediate priority.
Next opportunity I get I may pull the EGR crossover pipe to get a better look at the entire rear of the head/block.

flman · **Posted:** Thu Jan 22, 2015 9:52 am

Well keep an eye on your oil if your gonna put it off, the cooling and oil journals are pretty close in proximity.

WWDiesel · **Posted:** Thu Jan 22, 2015 5:51 pm

Since it does not appear to be a leak into the combustion chamber and it is leaking to the outside, I would seriously consider trying a good block sealer like K&N...Nothing to loose, and a lot to gain if it works.... :wink:

http://www.oreillyauto.com/site/c/detail/KW03/401016/N2359.oap?ck=Search_N2359_-1_-1&pt=N2359&ppt=C0180

Coolant Leak

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