Coolant Leak

[JeepGirl1013]

I did it!!! I found my coolant leak!! Very exciting as a novice mechanic

This radiator hose was very pregnant. So I’ll replace it tomorrow. But I still have questions.

The leak was pretty slow. Lost 1psi about every 1-2 min and it slowed to a stop around 15 psi. She’s not leaking while sitting- only while driving.

Also drained off a little oil during troubleshooting and I don’t know, but I’m guessing this is coolant in my oil?

I don’t fully understand how the coolant and other fluids tie together so is this indicative of an internal leak somewhere on top of the hose? Or could coolant be getting into the oil from the external leak that I found?

 

[hear]

What do you mean “you drained off a little oil?” What exactly did you do?

 

[JeepGirl1013]

What do you mean “you drained off a little oil?” What exactly did you do?

Following troubleshooting according to the service manual:

“Remove the engine oil pan drain plug and drain a small amount of engine oil. Coolant, being heavier than engine oil, will drain first.”

 

[Rickyd]

I don’t fully understand how the coolant and other fluids tie together so is this indicative of an internal leak

if you can't see tupy on the head when you look in the oil fill hole then i might suspect a cracked head. The tupy head was a factory fix for weak 0331 cylinder heads

Heres an older 0331 head crack seen from the oil fill hole. Note it doesn't say tupy

But i would also check for whiteish stains at hose connections,around the waterpump gasket and water pump weep holes for an external leak. Its hard to see from your pic if there is coolant in the oil

 

[JeepGirl1013]

if you can't see tupy on the head when you look in the oil fill hole then i might suspect a cracked head. The tupy head was a factory fix for weak 0331 cylinder heads

View attachment 493236

Heres an older 0331 head crack seen from the oil fill hole. Note it doesn't say tupy

View attachment 493238

But i would also check for whiteish stains at hose connections,around the waterpump gasket and water pump weep holes for an external leak. Its hard to see from your pic if there is coolant in the oil

She has a rebuilt engine so I hope it’s nothing that serious.

 

[ColoJeep]

She has a rebuilt engine so I hope it’s nothing that serious.

Take a photo of the bottom of the oil fill cap and a shot through the oil fill hole looking at the head through the hole.
Hopefully it's not serious , however some could have rebuilt the engine and reused the crack prone head to save money .

Think , " fix and flip " with more flip than fix.

 

[B1Toad]

Go online and order a Blackstone oil sample kit, when you receive it put in your sample and ship it USPS next day. (When Blackstone receives the sample by next day air they automatically get to it right away, otherwise it will take a couple of weeks). On the notes tell them you are concerned about coolant in the oil. It would not be the first time 4.0 got rebuilt and the same, cracked head re-used without the rebuilder knowing it was cracked, or even knowing it's a known issue on the 2000 to 2001 4.0 engine.

This is not something to fool around with, you need to find out asap and stop driving it till you know.

On mine (2000 4.0, rebuilt), when the cooling system was pressurized, a tiny drop of coolant appeared on top of the head that you could see thru the oil fill hole. I bought a Clearwater head and she is all good now.

 

[freedom_in_4low]

Hard to tell from a photo. does it feel like oil or coolant when you rub it between fingers? Does it smell more like one or the other?

The only thing I think i can see is that it doesn't look like oil and coolant mixed, it looks like it's mostly straight, whatever it is.

 

[macleanflood]

Also could be the head gasket. I redid the neighbor's head gasket on the WJ they bought. Definitely a fix and flip job. PO refreshed the engine with a new head gasket. Didn't seem properly torqued, looked like they reused head bolts. Lots of sloppy work evident...all suspicious no smoking gun other than the fan of coolant out the back of the engine between the block and head.

With all the other issues you've posted about it really looks like you need to check absolutely everything... I pretty much had to do the same thing on my 97. It's a 25 plus year old vehicle and pretty much needed a mini restoration.

Been chasing problems for three years and I keep thinking I'm done for a bit...just redid the thermostat and just bought a new temperature sensor because the gauge on the dash won't get over the what 160ish 1/4 line on the gauge.

Then I need to solve fuel pressure and occasional evap codes.

-Mac

 

[JeepGirl1013]

Update:

Replaced the upper radiator hose that was leaking. Lower was still in good shape.

Head Gasket - is there a way to check this without taking the engine apart?

Oil - looks and smells like oil to me. Will be changing it soon.

Whiteish stains at hose connections - I do not see anything like this

Water pump gasket- this seems fishy to me. This gasket has a lip on it? Now I got coolant everywhere last night. So I cleaned it up best I could.

Here is the gasket:

And here it is after pressurizing the cooling system:

I don’t think it was wet but I’m on the fence. Again, it was covered in coolant from last night and I do see the droplet of coolant by the belt but I think that’s from the spill.

Water pump weep holes - I can’t find these? Should I be able to see them without disassembling things?

Pic of cylinder head through oil fill hole:

Definitely not Tuffy. Would I be able to see an actual crack?

 

[JeepGirl1013]

i think I hit a limit for pictures…

Pic of oil fill cap:

Not gooey, the lump is actually malformed plastic.

Pressurized cooling system - cylinder head through oil fill hole:

Oil fill cap after system was pressurized:

I pressurized to 18 psi and it dropped to 17.5 after 5 min. Before I changed the radiator hose it dropped immediately very fast and hung out around 15psi.

So all in all- I’m hoping this was mainly a radiator hose issue. I think that water pump gasket needs to go at some point unless you all say otherwise. And I’m eager to hear your thoughts!

 

[JeepGirl1013]

Go online and order a Blackstone oil sample kit, when you receive it put in your sample and ship it USPS next day. (When Blackstone receives the sample by next day air they automatically get to it right away, otherwise it will take a couple of weeks). On the notes tell them you are concerned about coolant in the oil. It would not be the first time 4.0 got rebuilt and the same, cracked head re-used without the rebuilder knowing it was cracked, or even knowing it's a known issue on the 2000 to 2001 4.0 engine.

This is not something to fool around with, you need to find out asap and stop driving it till you know.

On mine (2000 4.0, rebuilt), when the cooling system was pressurized, a tiny drop of coolant appeared on top of the head that you could see thru the oil fill hole. I bought a Clearwater head and she is all good now.

Ordered the oil and transmission kits. Thanks for that suggestion. Would love to hear your thoughts on my updates.

 

[JeepGirl1013]

Take a photo of the bottom of the oil fill cap and a shot through the oil fill hole looking at the head through the hole.
Hopefully it's not serious , however some could have rebuilt the engine and reused the crack prone head to save money .

Think , " fix and flip " with more flip than fix.

Definitely not the new one. But hoping that I don’t need to do that swap quite yet…I’ve never even changed my own oil before

 

[ColoJeep]

Definitely not the new one. But hoping that I don’t need to do that swap quite yet…I’ve never even changed my own oil before

At least from the first look I don't see a huge issue ( Good ! ) most of the time you will see a creamy white " froth " under the oil fill cap if the coolant is getting into the oil. Yours looks OK . You really need to do the oil sample ASAP , this will tell the story . I can't tell what that dark stain is in the head photo , could be nothing , however it is in the area where the crappy 0331 heads fail. If the oil sample shows high coolant contamination stop driving it immediately at have a mechanic evaluate it further . What happens if you keep driving and getting coolant in the oil is it will ruin the bearings / crankshaft . And your rebuilt engine is toast.
If detected early you can likely just have the head replaced , ( With a rebuilt TUPY or Clearwater head ). All the best for you moving forward !

 

[hear]

Those pics were of your oil pan gasket, fyi. And it looks fine.

The water pump uses a thin paper gasket, although you may find that a previous set of hands used RTV there. The weep hole isn’t really visible, it’s up there below the fan shaft. If the bearing is starting to go it will leak from that weep hole and you’ll see it on the ground basically right under that main pulley. And the main pulley will be wet too iirc.

So far I haven’t seen anything that give me cause for alarm, but sending your stuff off for analysis won’t hurt.

 

[B1Toad]

On mine the crack was very tiny and there was a slight trace of slime following it, you could wipe away the slime but underneath you couldn't visually see a crack. The only way you knew there was a crack was when the system was pressurized there was a tiny green droplet forming there (mine had green coolant in it at the time so that showed up with a bright light). My symptoms were disappearing coolant with no visible leaks, and the oil was over full. I wrongly assumed the previous owner had over filled the oil. In my case the oil had not yet whipped itself into a milkshake which is what happens after the coolant has been in there a while, but the Blackstone test revealed a large concentration of coolant (they called me on the phone immediately). As soon as I found that out is when I started to investigate and found the crack.

The PO sold it to me with a rebuilt engine just like yours but they re-used the non-TUPY head. I should have been more diligent in my pre-purchase inspection but to be honest it was such a pristine and rust free Jeep that even if I had known about the head I still probably would have wanted it, but I might have been able to get a bargain on it instead of paying top dollar like I did. It's been a year and after the head replacement I am totally happy with it, and I feel a special attachment to it especially having had it all torn apart in pieces on the garage floor, I know I can fix anything on it, and working on these is so simple compared to most vehicles now. It has, however cost me more than I expected and my list of "wants" got put aside for the list of "needs". On the bright side it hasn't cost near what a new one would cost and it's all mine free and clear.

 

[B1Toad]

Ordered the oil and transmission kits. Thanks for that suggestion. Would love to hear your thoughts on my updates.

The USPS next day will cost you about $28 but well worth not having to wait 2 weeks. Once you are straightened out you can go to the regular free shipping on any future samples you may want to do. They also sell a dipstick tube pump that you can use to pull samples right out of the dipstick tube, be sure to warm up the engine a bit first.

 

[B1Toad]

Below is a picture of a new head, I drew a green line where mine was cracked. It was right at the base of that rocker arm tower, so to the upper-middle passenger side of the oil fill hole when looking from the front of the engine. Much easier to see with the valve cover removed which by the way is a pretty easy job. Like I said earlier there was a tiny green droplet and a tiny trace of dark slime following the crack that you could wipe away with your finger but still not see the actual crack itself.

If it turns out you need a head you can get a Clearwater fully assembled with a warranty shipped for $650 https://www.cylinder-heads.com/product/new-jeep-cherokee-laredo-4-0-0331-cylinder-head-complete/

 

[Rickyd]

Its hard to tell,but this line looks like maybe a crack? The oil analysis would be a good idea

 

[JeepGirl1013]

At least from the first look I don't see a huge issue ( Good ! ) most of the time you will see a creamy white " froth " under the oil fill cap if the coolant is getting into the oil. Yours looks OK . You really need to do the oil sample ASAP , this will tell the story . I can't tell what that dark stain is in the head photo , could be nothing , however it is in the area where the crappy 0331 heads fail. If the oil sample shows high coolant contamination stop driving it immediately at have a mechanic evaluate it further . What happens if you keep driving and getting coolant in the oil is it will ruin the bearings / crankshaft . And your rebuilt engine is toast.
If detected early you can likely just have the head replaced , ( With a rebuilt TUPY or Clearwater head ). All the best for you moving forward !

Thank yo

Its hard to tell,but this line looks like maybe a crack? The oil analysis would be a good idea

View attachment 493386

Tried to zoom in and enhance the details a bit