Mystery Coolant Leak

[JDS123]

Hi all,
I noticed that my 4.0 has been leaking coolant pretty quickly so I took it to get the system pressure tested. When the shop did the pressure test, they noticed that the system lost pressure but no coolant was leaking. They gave me the jeep back, saying to put a new radiator cap on in case that was the issue. I did that today and the issue is still there. Coolant is hitting the belt and spraying up onto the hood when I'm driving. I opened the hood while keeping the engine at around 2000 rpm and didn't see any coolant flying off the belt. The jeep runs and drives perfectly. It doesn't overheat, the fan shuts off like normal, and the exhaust doesn't smoke.

Anybody have an ideas on what the source of the leak could be?

 

[KCsTJ]

You might check the oil dipstick, if u see small bubbles or a foamy appearance in the oil on the dipstick (lets hope not) that would mean coolant in the oil. If the dipstick oil looks normal you can prob rule out bad cyl head gasket

 

[JDS123]

You might check the oil dipstick, if u see small bubbles or a foamy appearance in the oil on the dipstick (lets hope not) that would mean coolant in the oil. If the dipstick oil looks normal you can prob rule out bad cyl head gasket

I checked the oil yesterday because I thought it was oil leaking at first. Oil level is normal and looks fine. Oil was also changed less than 200 miles ago so I'd imagine they would have told me if there was a problem. I'm a bit worried about a head gasket, but it doesn't seem to be blown.

 

[sgtjdgelinas]

Check the water pump at the pulley, I had a GM that was leaking from a bad bearing and getting on the belt. It was hard to spot at first.

 

[weldedcambolt]

my upper hose on the motor was leaking, but couldnt see it. kept tighting the hose clamp, but sooner than later it would start leaking again. replaced the hose clamp, which is a bit to get in between the housing an the valve cover, but the new clamp, fixed the leak. if they were using the pressure , an fluid was low, they may not be able to see a leak, cause only air was leaking out.

 

[JamesAndTheSahara]

Hi all,
I noticed that my 4.0 has been leaking coolant pretty quickly so I took it to get the system pressure tested. When the shop did the pressure test, they noticed that the system lost pressure but no coolant was leaking. They gave me the jeep back, saying to put a new radiator cap on in case that was the issue. I did that today and the issue is still there. Coolant is hitting the belt and spraying up onto the hood when I'm driving. I opened the hood while keeping the engine at around 2000 rpm and didn't see any coolant flying off the belt. The jeep runs and drives perfectly. It doesn't overheat, the fan shuts off like normal, and the exhaust doesn't smoke.

Anybody have an ideas on what the source of the leak could be?

Please share some photo’s. Its very likely you have a worm drive clamp on and you need a constant tension clamp. Ask me how I know.

 

[weldedcambolt]

if for some reason, you change the water pump an put on a higher pressure water pump, flowcooler, make sure, the bolts are all the same thread size with the fan mount. the bolts didnt match up to the flowcooler, an i almost would have stripped them, but seen a post about, people stripping them, an stopped before i stripped them. i call them up to find out what bolt size they were using in the flowcooler to bolt on the fan blade, but, i couldnt get an answer from them, an had to trial an error at the hardware store to get the right ones. an dont open the cap, with the motor running, that high flow will throw coolant at you out the cap like a major leager. it does keep the temperature down about 20 degrees on my gauge.

 

[JDS123]

Please share some photo’s. Its very likely you have a worm drive clamp on and you need a constant tension clamp. Ask me how I know.

I'd imagine that a wrong clamp would cause a leak immediately after being installed. Am I wrong about that? Cooling system hasn't been opened up in about 1.5 years.

my upper hose on the motor was leaking, but couldnt see it. kept tighting the hose clamp, but sooner than later it would start leaking again. replaced the hose clamp, which is a bit to get in between the housing an the valve cover, but the new clamp, fixed the leak. if they were using the pressure , an fluid was low, they may not be able to see a leak, cause only air was leaking out.

I filled the coolant before I took it to the shop. Drove all the way there fine without overheating and the shop only had to add a very small amount of coolant to get it back up to the regular amount before I picked it up. It certainly is a possibility that only air was escaping, though.

Check the water pump at the pulley, I had a GM that was leaking from a bad bearing and getting on the belt. It was hard to spot at first.

The shop did say the pump was a possibility and logically it makes sense. But when a water pump fails, doesn't it typically just leak out the weap hole slowly? This seems to be a much larger leak than that.


So I'm going to take it back to the shop on monday and leave it with them for a few days. Any recommendations on what tests I should ask them to do? I'm thinking about another pressure test and then a carbon test to rule out a head gasket.

 

[JamesAndTheSahara]

I'd imagine that a wrong clamp would cause a leak immediately after being installed. Am I wrong about that? Cooling system hasn't been opened up in about 1.5 years.



I filled the coolant before I took it to the shop. Drove all the way there fine without overheating and the shop only had to add a very small amount of coolant to get it back up to the regular amount before I picked it up. It certainly is a possibility that only air was escaping, though.



The shop did say the pump was a possibility and logically it makes sense. But when a water pump fails, doesn't it typically just leak out the weap hole slowly? This seems to be a much larger leak than that.


So I'm going to take it back to the shop on monday and leave it with them for a few days. Any recommendations on what tests I should ask them to do? I'm thinking about another pressure test and then a carbon test to rule out a head gasket.

Its not that the clamp wouldn’t work, but when the hose expands and contracts it cases a weep at an upper or lower location. I need to replace mine but just top off coolant every other month.

 

[weldedcambolt]

I tried for a day to find those constant pressure clamps, at all auto parts stores, no one carries them anymore. oreillys had some constant pressure clamp, but wouldnt fit, on the car i was working on. an the price at the dealer for them, are sky high, even them guys at the parts dealer counter look like, you sure you want these at this price. if that new one starts leaking i put on, i will be getting it from the dealer.

 

[TJ4Jim]

I tried for a day to find those constant pressure clamps, at all auto parts stores, no one carries them anymore. oreillys had some constant pressure clamp, but wouldnt fit, on the car i was working on. an the price at the dealer for them, are sky high, even them guys at the parts dealer counter look like, you sure you want these at this price. if that new one starts leaking i put on, i will be getting it from the dealer.

Check out Amazon for the clamps, they are available.

 

[weldedcambolt]

I would order a top hose constant pressure clamp from the dealer for it, if the top hose is old, get a new one, an try that first. if you can get in there with a flash light, without gettting eaten by the fan, you can see the top hose leaking on either side of the thermostat housing, if thats it. on mine it was a fine line of coolant running down i could barely see. my water pump was leaking before that, an i replaced that, but did not replace the top clamp for the top hose, so ran into that problem of the top hose clamp not tightening enough. an at first seeing it leaking again, after i just replaced the water pump, it wasnt good, but worked thru it to find the top hose leakin from the old clamp not being able to tighten properly, an the new water pump was okay.

 

[weldedcambolt]

https://www.amazon.com/dp/B007O3S0BW/?tag=wranglerorg-20 11.25 for a clamp, crazy

 

[weldedcambolt]

 

[KCsTJ]

My Tjs coolant leaked out slowly for awhile, turned out to be a loose accessory belt, could smell coolant but no leak seen
The belt was just tight enough to turn the accessories but allowed slippage around the water pump pulley
So I think it slightly overheated boiling out the coolant.
I'm sure your belt is tight, just sompm to check

 

[ac_]

Does your tj have an overflow tank? It is possible for the waterpump to intermittently drop water out of the weep hole. It is rare but there is a seal in there and maybe the water overcomes it intermittently. But that said pumping up the system should overcome the seal if it is at all bad so if they pumped it up and it wasn't leaking that probably is not your problem and even if it is intermittent you should see a dried green trail coming from it.

The reason why I asked if you have an overflow bottle is if you don't and you fill the radiator to the top it will blow water out of the tube hole right into your fan. So if you don't have an overflow bottle you don't want to fill the radiator up all of the way let it low about a 1/2 inch low in the radiator. Also put a hose down the side of the radiator so if it does blow water it blows it straight on the ground and not all over your hood.

My last suggestion without looking at it is maybe a pinhole leak in one of your radiator hoses. I t could be blowing a tiny stream barely noticeable. I am sad that you took this to a shop and they admitted you have a loss of pressure but just gave up on it? If you are losing pressure something is wrong.

Oh one more thing if you don't have an overflow bottle replace your radiator cap. It as a steam pressure relieve valve and will release steam at a certain pressure. IF it is bad it could be happening early. Also another reason to not fill your radiator all of the way to the top.

Just to alleviate confusion, if you do have a overflow, then it does get filled all of the way to the top. oh and check the overflow bottle if you have one but it won't explain why you are losing pressure but if it is cracked it could leak.

 

[derekmac]

It is possible for the waterpump to intermittently drop water out of the weep hole.

That was my first thought.

 

[JDS123]

Does your tj have an overflow tank? It is possible for the waterpump to intermittently drop water out of the weep hole. It is rare but there is a seal in there and maybe the water overcomes it intermittently. But that said pumping up the system should overcome the seal if it is at all bad so if they pumped it up and it wasn't leaking that probably is not your problem and even if it is intermittent you should see a dried green trail coming from it.

The reason why I asked if you have an overflow bottle is if you don't and you fill the radiator to the top it will blow water out of the tube hole right into your fan. So if you don't have an overflow bottle you don't want to fill the radiator up all of the way let it low about a 1/2 inch low in the radiator. Also put a hose down the side of the radiator so if it does blow water it blows it straight on the ground and not all over your hood.

My last suggestion without looking at it is maybe a pinhole leak in one of your radiator hoses. I t could be blowing a tiny stream barely noticeable. I am sad that you took this to a shop and they admitted you have a loss of pressure but just gave up on it? If you are losing pressure something is wrong.

Oh one more thing if you don't have an overflow bottle replace your radiator cap. It as a steam pressure relieve valve and will release steam at a certain pressure. IF it is bad it could be happening early. Also another reason to not fill your radiator all of the way to the top.

Just to alleviate confusion, if you do have a overflow, then it does get filled all of the way to the top. oh and check the overflow bottle if you have one but it won't explain why you are losing pressure but if it is cracked it could leak.

I have an overflow bottle. The shop didn't really give up, they just weren't sure. I took it back before they did anything else to try some things myself. I'm going to bring it back so they can get a more in depth look at it. I would do it myself but unfortunately, I have no where to do work on the jeep while I'm at college.

The pinhole seems less likely because the leak is intermittent. I can drive it for miles and have no leak. Then I fire it back up the next day, drive a quarter mile and the hood is covered in coolant. It is definitely something to check.

That was my first thought.

I certainly could be the water pump and thats my suspicion too. This water pump is a year and a half old but it is from Napa, which I never trust. What is the best brand of water pump to put in a TJ? The only thing that confuses me is the fact that it didn't leak when they pressure tested it.

I have a suspicion that the leak may go on and off with RPM. Would that indicate water pump? I opened the hood and used the hand throttle to set it at 2000 rpm and saw no leak. The hood had some coolant on it so it was leaking when I driving no less than 2 minutes earlier. That leads me to believe that maybe it starts leaking once I get to higher RPM.

 

[Blank]

mine had a leak a while back and i couldnt figure it out to save my life then i looked right after i shut it off and boom there is was a cracked radiator the top plastic piece had cracked

 

[Shaggy]

Please share some photo’s. Its very likely you have a worm drive clamp on and you need a constant tension clamp. Ask me how I know.

Okay I'll bite how do you know? I have a leak from the top of the lower radiator hose. Replace hose twice and and worm drive type clamps 4 times now. Sometimes leaks, sometimes doesn't.