WTF? Coolant leak- HELP

L

LoneRanger

NAXJA Forum User
Location
Jacksonville, Fl
Drove to breakfast this morning, noticed a leak in what I "thought" was the radiator hose. no biggie, I can fix that-


take her home get in the "other" car and go to auto store for a haynes manual or the like and a new thermostat, a temp coolant sensor, and a new hose. get back home the engine is cool enough to touch now and i get to investigating things, fill up with h2o and turn on truck, 4-5 mins later I get a leak when I intentionaly TRIED to force water out of the hose- but it was not water comming out of the hose- it was a stream blowing out the back side of the motor itself. Holy Shit that is NOT normal I think to myself as I try to keep my cool. (my wife was standing near by watching me) so freaking great- I'll let the pics do the rest of the talking.

post-11-72666-rust_puddle.jpg
post-11-72739-leakspot.jpg
post-11-72827-leakingspot.jpg




for thoes that dont know i have owned this truck for approximaetly 4 days now, the check engine light came on as I was driving back home (4 hours) the tranny would not shift into 4th(O.D.), and now this. I was fully expecting to do general maintence (TPS sensor, Temp sensor, water pump, etc... ) But this? WTF

ANY HELP? 1999 Clasic, 4x4, 4.0L, auto tranny


I am going to post this in every jeep forum I can find-


L.R. :mad:
 
Freeze plug on the back of the head... I had it happen to me but it wasn't streaming out like that.. Unfortunately the head has to come off to replace that $1 freeze plug. Some others might chime in here with some help.

George Trilikis
00XJ
 
Looks like a rotten freeze plug on the back side of the head to me. Or, it could be on the back of the block. Either way, not a simple fix. May require engine pull. just my 2 cents. I could be wrong.


EDIT:
Check page 2D-8 in your haynes repair manual.
Aaron
 
Before jumping to conclusions, are you sure it isin't coming from the heater hoses or coolant temp sender which are near the rear of the engine. Sorry for the idiot question anyway.

Edit: On my second look at the bottom picture that really a jet of water coming out back of the engine not from some other component.

I'm thinking blown head gasket or cracked head, loose freeze plug like already mentioned. Damn that would be one hell of a crack to squirt like that. Either way its not all that much trouble to replace on an I-6 jeep. There is a known pattern failure (cracking) on the 0331 head casting which I believe were installed some time around your year. Diddn't think that was the typical spot though. You can replace the head with different HO casting, 0630 or 7120 numbers I believe. You should be able to get part at junkyards and relatively cheaply and then have it reconditioned by a machine shop and it will provide many thousands of trouble free miles. Odds are your lower block is good and is only 99 so not too many miles, unless there has coolant in the oil for a long time.

I would start by crawling in there and trying to find where the water is coming from. Head or the block? Appear to be the head gasket or a plug? Take it to a machine shop anyway and have it magnafluxed (inspected for cracks with magnetic dye) here I can get that done for $15-20. Head off of course.

Also is that DexCool youre running or straight (rusty) water? Also, are you suspecting that the seller knew about this?
 
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I dont know if he knew about it or not. I also dont know if it is DexCool or rusty water lol. (I am thinking rusty water) the jeep is a 99' with 138K on the ticker. I got the 99' specificaly because the cracking of the heads were NOT on my year jeep, they were 2000+ models (I thought) I did mucho research before buying and came to the Unanamous conclusion that a 99 was the BEST year to buy.

L.R.
 
Well, youre entitled to my opinion that 95 is the best year cherokee for many reasons ok :D

Anyway, if its rusty tap water thats no bueno because coolant needs to have the different chemicals that not only neutralize acidity, prevent dissolved solids from settling and also prevent the corrosion of metals like copper/brass (freeze plugs, radiators) aluminum (radiators, water pumps, various components) and lubricate the water pump bearing. If Jeep diddin't think using antifreeze this was necessary for all engines (not just cold climate) they wouldn't go through the expense of adding antifreeze straight from the factory. Water is a solvent, a very universal one. It will dissolve anything given enought time. HOT water is even better than dissolving metals.

So, find the source of the leak, repair (get it magnafluxed anyway its a few bucks if the head comes off). And if its straight tap water in there for a long time other cooling components could fail prematurely. Flush the system at least.

Also, to tell if something is antifreeze I just lick my finger and then go rinse my mouth out. Should taste like mountain dew. :gag:
 
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Use a small inspection mirror to see behind the head. Most likely you have a leaking core plug. Good news is they are easy and inexpensive to replace, IF, you have access to the rusted-out plug. It would appear you need to pull the head or consider cutting a hole in the firewall(probably not feasible). More bad news--when one core plug fails do to rust, the rest may not be far behind; you just never know when the next one is going to let go. Best advise, replace them all at the same time. Of course, this may require pulling the engine to do the job right.
 
Very good point and a very good suggestion. I did the same thing when mine went. Sorry to say it but these are some of the problems that arise when you purchase a used vehicle. Especially when you dont know the previous owner or how they maintained there investment.
Not to sound redundant, if one is bad there will be others soon to follow. just MHO.
 
Just an FYI- here is a pic of the 4.0L blockl, I dont think it is going to be the plug because the transmission completly covers the plug when it is bolted on. I am leaning towards the head gasket.


plug.jpg



L.R.
 
LoneRanger said:
Just an FYI- here is a pic of the 4.0L blockl, I dont think it is going to be the plug because the transmission completly covers the plug when it is bolted on. I am leaning towards the head gasket.
Click to expand...

There most certainly is a freeze plug at the back of the cylinder head, not just the lower block in front of the tranny. I just visually confirmed its presence.
 
That is indeed a bad freeze plug. As has been stated already, it would be best to replace them all. I feel that it is easier to replace them by pulling the tranny down, instead of pulling the motor.( let's see: pull D/S, drop t-case, drop tranny, Pull motor: exhaust fuel lines{ going to need new "o"rings for lines, pull rad. pull a/c pump{place to side if charged, with lines still hooked up}, P/S pump, etc... Yeah, less work to drop tranny). By the way, if you use BRASS plugs for replacements, they will not rust, and will still work as a "freeze" out plug. Pioneer makes them. Ask for them at the parts counter.
Oh, yeah, go ahead and change the tranny mount, since you are there and it is most likely shot.
As for the plugs on the drivers' side, either way you go, you will have to pull the mainfold assembly. The good news is that the plugs can be changed without having to pull the mount loose and there are NO plugs on the passenger side, since that side is all oil gallery, no water jackets.
 
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You all were correct it IS the freeze plug, I stuck my finger in there and confirmed it. SO the head of the motor HAS to come off huh? how much work is that exactly? lol

and what do I need to do to get to the Other plugs?


what am I looking at so far as cost? materials alone assuming I am going to do the job myself (with some help I hope) new bolts for the head, new gasket, new water pump, new plugs, new H2O temp sensor, new???? Radiator possibly even?


L.R.
 
Read my post, and you will have a better understanding of how to get to the plugs. As for how much $? depends on cost down there. You can pretty much bet on it being a good idea to replace the water pump, considering what came out of the motor. I would see about having the rad. hot tanked, if it has been holding temp. o.k., then back flushing the entire cooling system a few times would be a good idea also.
 
Yeah it isin't necessary to replace the rad entirely but it might fail with fewer than expected number of years. Definetly a good flushing and see what happens from there (as far as operating temps go). Of all those items I believe the pump is the most expensive I think mine was $35, then theres the head gasket, valve cover gasket and head bolts which I've heard are a challenge to find. Get a thermostat but visually inspect the thermo housing and sensors for corrosion before commiting to purchase.

Head gasket r&r on a 4.0 isin't bad, considering what you go through with a lot of other cars of the same year.
 
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Yeah, that sounds pretty reasonable, ESPECIALLY when you have help to do it. ( I never get lucky enough to have help on this kind of stuff, only on the "little" things.)
 
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