Coolant leak behind the engine - Can't locate it

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Farking Bastage

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This is a 2003 V8. She started overheating on me and I noticed the upper hose was cracked and it had lost coolant. I replaced that, performed a coolant flush/fill/purge and after testing 10 minutes at a time or so it seemed to be good.

On the way home yesterday, I heard the fan go high again, but didn't seem to totally overheat. When I got out, I smelled coolant, took a look underneath and there's coolant pouring out dead center directly where the engine and bell housing meet. That made me think it's the puke bottle or one of the lines going to it. I currently have the cowl and that brace pulled off it and I'll be damned if I can find the leak or any evidence of one. The PITA is I can't reproduce it unless I drive it for a good 20 minutes or so.

Degas bottle hose connection http://i.imgur.com/bR8mk.jpg

Junction between Degas return and air bleed hose http://i.imgur.com/WyKQK.jpg

Any idea where that could be coming from?
 
The only thing I can think of would be the heater core or the pipes leading to it. I don't think there is anything else involving coolant on the center rear of the engine bay.
 
it's so tight back there I really can't get a good look at it even with the cowl removed.

I bet that core is expensive as hell
 
Question: With the heat off, does coolant still flow through the heater core like older vehicles or does it have some sort of a bypass.

The reason I ask is that the only condition I haven't tested yet is driving for a long time with the heater on ( really fun in FL in June ) assuming there is some sort of bypass in there that could be picking up the leak.
 
I believe, and I could be wrong, that the dccv acts as a bypass when the heat is off. The heater core may not be expensive but getting it replaced cant be any fun. I wouldn't even know where to start.
 
Farking Bastage said:
Question: With the heat off, does coolant still flow through the heater core like older vehicles or does it have some sort of a bypass.

The reason I ask is that the only condition I haven't tested yet is driving for a long time with the heater on ( really fun in FL in June ) assuming there is some sort of bypass in there that could be picking up the leak.
Click to expand...

With the heat off, the coolant does not flow through the heater cores. However, if there is a leak, it will back-feed and pour out.

That said, I think that it is much much more likely that your degas bottle is cracked. You really can't see the cracks without removing the degas bottle completely. Even then, they won't seem like the problem until you heat it up and pressurize it. (Many degas bottles have failed. Hardly any heater cores have.)

Once you replace the degas bottle and correctly bleed the air out by following the bleed procedure exactly (see below), you will soon find the you also need to replace the coolant outlet pipe, the thermostat housing, and a few other plastic parts. Usually, when one fails, the others will be close behind.

http://deneau.info/ls/s6x~us~en~file=s6x33004.htm~gen~ref.htm#extract_142
 
I should add that if you didn't exactly follow the factory air bleed procedure, that might be your only problem. (If there is trapped air, the coolant will boil. If the coolant boils, the pressure relief in the degas bottle cap will vent coolant exactly where you describe.)
 
Looks like that manifold block near the heater core.
Couldn't get a pic because of the location.
I was on the 2k RPM step of the purging process and coolant started pouring out of the back of the engine again.

Underneath It was running down that flange on the side of the bell housing,

http://i.imgur.com/wj1uA.jpg

http://i.imgur.com/AtlWb.jpg

right in the center of that rectangular aluminum block where all the lines converge, I saw some moisture. it's really hard to see it even with the cowl removed.

:q:q:q:q..
 
Farking Bastage said:
Looks like that manifold block near the heater core.
Couldn't get a pic because of the location.
I was on the 2k RPM step of the purging process and coolant started pouring out of the back of the engine again.

Underneath It was running down that flange on the side of the bell housing,

http://i.imgur.com/wj1uA.jpg

http://i.imgur.com/AtlWb.jpg

right in the center of that rectangular aluminum block where all the lines converge, I saw some moisture. it's really hard to see it even with the cowl removed.

:q:q:q:q..
Click to expand...

Are you talking about the AC manifold? (The part with some red coloring in the diagram.) If so, then that's just condensate water from the cold AC lines and not the source of your leak. That would explain why the pictures show clear water and not green/yellow/gold coolant.

AC_Manifold.JPG
 
Farking Bastage said:
This doesn't appear to be part of the heater core and I really have no idea what the part is

http://i.imgur.com/emdou.jpg
Click to expand...

Yep, that's the end of the "Thermostatic Expansion Valve Manifold and Tube Assembly." This is part of the AC refrigerant loop. The water is just condensation from the air because of how cold the AC pipes get. It's just like a glass of ice water "sweating."
 
I guess the only other thing it could be is one of the hardlines between the degas bottle and where it connects to another rubber hose on the passenger side. The connection sites are bone dry and it is leaking from somewhere I have no means to get to.

Everywhere I can get a flashlight seems ok, so it must be that hardline around the ass end of the engine.

Screw it... time to get the vaseline out I guess.
 
It's got to be that hardline. Both rubber ends are bone dry fully pressurized, but that hardline is really the only thing back there that's running coolant ( besides the heater core which I am fairly certain is ok )

I know a guy in town who runs a damned honest shop ( if his conduct on a golf course is anything to be believed ), so I'm going to take it to him.

I appreciate it guys.
 
Farking Bastage said:
This is a 2003 V8. She started overheating on me and I noticed the upper hose was cracked and it had lost coolant. I replaced that, performed a coolant flush/fill/purge and after testing 10 minutes at a time or so it seemed to be good.

On the way home yesterday, I heard the fan go high again, but didn't seem to totally overheat. When I got out, I smelled coolant, took a look underneath and there's coolant pouring out dead center directly where the engine and bell housing meet. That made me think it's the puke bottle or one of the lines going to it. I currently have the cowl and that brace pulled off it and I'll be damned if I can find the leak or any evidence of one. The PITA is I can't reproduce it unless I drive it for a good 20 minutes or so.

Degas bottle hose connection http://i.imgur.com/bR8mk.jpg

Junction between Degas return and air bleed hose http://i.imgur.com/WyKQK.jpg

Any idea where that could be coming from?[/
Click to expand...
Farking Bastage said:
This is a 2003 V8. She started overheating on me and I noticed the upper hose was cracked and it had lost coolant. I replaced that, performed a coolant flush/fill/purge and after testing 10 minutes at a time or so it seemed to be good.

On the way home yesterday, I heard the fan go high again, but didn't seem to totally overheat. When I got out, I smelled coolant, took a look underneath and there's coolant pouring out dead center directly where the engine and bell housing meet. That made me think it's the puke bottle or one of the lines going to it. I currently have the cowl and that brace pulled off it and I'll be damned if I can find the leak or any evidence of one. The PITA is I can't reproduce it unless I drive it for a good 20 minutes or so.

Degas bottle hose connection http://i.imgur.com/bR8mk.jpg

Junction between Degas return and air bleed hose http://i.imgur.com/WyKQK.jpg

Any idea where that could be coming from?
Click to expand...
 
My 2005 lincoln ls v8 was having the same problem. I had a leak coming from the degas bottle and also a tiny crack on thermostat housing I got all that taken care of but it seemed to still be leaking. Came to find out that the plastic hose under the intake had a hole in it. Look at the thermostat and follow it thru with a flashlight since the car is a little cramped out hopefully you will see the leak there and that would solve your problem. It should be the plastic t hose right under intake that connects to the heater hoses. It's only a 60 dollar part .
 
Avila 4600 said:
My 2005 lincoln ls v8 was having the same problem. I had a leak coming from the degas bottle and also a tiny crack on thermostat housing I got all that taken care of but it seemed to still be leaking. Came to find out that the plastic hose under the intake had a hole in it. Look at the thermostat and follow it thru with a flashlight since the car is a little cramped out hopefully you will see the leak there and that would solve your problem. It should be the plastic t hose right under intake that connects to the heater hoses. It's only a 60 dollar part .
Click to expand...

So, it's actually a rubber hose that goes to the throttle body heater. The one on my 06 looked like it was ready to split (not leaking yet) so I replaced it. The one on my 04 is still going strong, so maybe it is the luck of the draw.

Anyway, we really do appreciate the help, but do be aware that FB had that problem over five years ago. Either he solved it years ago, or got rid of the car. He last logged onto this site in early 2013. His last comment of "intake manifold gasket" is odd, since no coolant flows through that.
 
Farking Bastage said:
This is a 2003 V8. She started overheating on me and I noticed the upper hose was cracked and it had lost coolant. I replaced that, performed a coolant flush/fill/purge and after testing 10 minutes at a time or so it seemed to be good.

On the way home yesterday, I heard the fan go high again, but didn't seem to totally overheat. When I got out, I smelled coolant, took a look underneath and there's coolant pouring out dead center directly where the engine and bell housing meet. That made me think it's the puke bottle or one of the lines going to it. I currently have the cowl and that brace pulled off it and I'll be damned if I can find the leak or any evidence of one. The PITA is I can't reproduce it unless I drive it for a good 20 minutes or so.

Degas bottle hose connection http://i.imgur.com/bR8mk.jpg

Junction between Degas return and air bleed hose http://i.imgur.com/WyKQK.jpg

Any idea where that could be coming from?
Click to expand...
joegr said:
So, it's actually a rubber hose that goes to the throttle body heater. The one on my 06 looked like it was ready to split (not leaking yet) so I replaced it. The one on my 04 is still going strong, so maybe it is the luck of the draw.

Anyway, we really do appreciate the help, but do be aware that FB had that problem over five years ago. Either he solved it years ago, or got rid of the car. He last logged onto this site in early 2013. His last comment of "intake manifold gasket" is odd, since no coolant flows through that.
Click to expand...
Yeah my leaks were bad tho I was buying antifreeze almost everyday. What I was thinking was that it all started with that leak under the intake that I didn't know about but it started as a crack then eventually it made the thermostat crack then the degas bottle. Then the hole in the rubber hose grew.my car was still good even with those leaks because not all the pressure was coming out of just one part. It would only overheat if the degas bottle was very low on coolant. Then I had replaced the thermostat and it just got worse. The replacement made the degas bottle leak even more from more pressure and the rubber hose as well but not as bad as the bottle. The car was still overheating now with one less leak regardless if I topped it off or not. Then the bottle was replaced, the car again over heated but not as before. The fans would turn on and stay on. Sometimes it would take the guage to get in the middle so It can overheat, sometimes it would take a 20 min drive for it to over heat. Now the only leak was under the intake and like I said it grew. It took an inspection camera to see that. Got that replaced too and there it was, no more overheating no more leaks. The car ran like new. My leak was just like yours, in the middle of the engine but noticable under the car. How's your Ls now tho?
 
Let me stop you right there. No need for these odd theories. The fact is that all the plastic parts of the cooling system degrade at about the same rate. As soon as you realize one is leaking, then you need to replace all of them at the same time. If you pay close attention to it, you will see the signs (slight residue and so on) long before the engine experiences any overheating and before you even have to add coolant.

I'm not sure why you say "My leak was just like yours," since I haven't related any leak here. I replaced that hose because it looked like it might fail soon. It wasn't actually leaking yet. One of the plastic parts had just started to weep at that time, so I replaced it all.

Both of my LSes are doing just fine, thank you. I have replaced all the plastic parts on my 06 once (including the radiator), and twice on my 04 (radiator only once though).
 
joegr said:
Let me stop you right there. No need for these odd theories. The fact is that all the plastic parts of the cooling system degrade at about the same rate. As soon as you realize one is leaking, then you need to replace all of them at the same time. If you pay close attention to it, you will see the signs (slight residue and so on) long before the engine experiences any overheating and before you even have to add coolant.

I'm not sure why you say "My leak was just like yours," since I haven't related any leak here. I replaced that hose because it looked like it might fail soon. It wasn't actually leaking yet. One of the plastic parts had just started to weep at that time, so I replaced it all.

Both of my LSes are doing just fine, thank you. I have replaced all the plastic parts on my 06 once (including the radiator), and twice on my 04 (radiator only once though).
Click to expand...

So wait, I'm confused. I am having this exact issue. I've. Changed all plastic parts, to include the radiator. I have the telltale green coolant leaking from the back of the engine. I also cannot see what it is because it's a tight fit at the back of the engine bay. I'm really trying to figure this out. Please help, I saw it's a heater core hose, a degas bottle hose, etc. I've changed to a new bottle and everything.
 
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