Unpinable coolant leak

[Ryanthelsman]

I got another problem id love too get some feedback on! I own a 2004 lincoln ls 3.9 v8. Its a project and the previous owner took awful care of the car and neglected it and im trying too save this forgotten gem. Anyways… i have a coolant leak that i cant pinpoint. It drips right before the oil pan and under the belts and such. But the leak is some where behind the oil filter. All the nearby lines are bone dry and I suspected it was the water pump failing but it was dry as well and fairly new looking. It must be something out of veiw as i cant see the source from directly under the car or from the engine bay. The leak wont be apparent untill the car fully warms up and it will slowly start too drip down and then randomly just gush out a stream of fluid then stop entirely and do this over and over. I recently replaced the main coolant line near the top of the engine bay (known for cracking) as it was leaking and have put all new coolant AND done the pressure release… thing.. forgot the name lol. It didn’t do this till recently. I can take a picture and send it in the morning if my jumbled description is confusing.

 

[JustALs]

not a pro but just pitching this
seen some leak at the thermostat housing o ring and even the cap o ring did you check those?

also there's a small coolant hose on the left side of the radiator that goes on the auxiliary pump to the dual climate control valve,, and can somehow get close to one of the pulley, happened on mine a while back and cause a leak.
goodluck

 

[joegr]

As always, ALL of the plastic cooling system parts need to be replaced with OEM, and there is a throttle body heater hose that is mostly under the intake manifold that is known to fail. Lastly, clean the cooling port surfaces at the front of the heads really well. Always use new gaskets.

 

[Ryanthelsman]

this is where the leak is dripping from. Everything above the Alternator and some below is bone dry. so the thermostat stuff and others were dry as well when i checked this morning.

 

[JustALs]

nice ls looks clean under ,,
right on top of that block where the oil filter screws on theres a coolant hose or two leak might be from there

 

[nghtshd88]

I had coolant there in the exact same place, couldn't find it either for a while but def smelt it. Happened to be the crossover O-ring (design flaw) that pushes onto the elbow on top of the motor. Its very hard to see the leak without removing things and in between was dry also so I didnt believe it was leaking from the top. Did the same thing, not leak until warmed up then stop then would leak again and stop when cold. Also had the DCCV leak at the seams, very hard to pinpoint..

Edit: Forgot when my radiator went shortly after it also leaked off of the oil filter and belly pan, depending how you park and drive it will run to different spots..

It seems if you plug one hole the pressure finds the next weak spot.

 

[rgorke]

As always, ALL of the plastic cooling system parts need to be replaced with OEM, and there is a throttle body heater hose that is mostly under the intake manifold that is known to fail. Lastly, clean the cooling port surfaces at the front of the heads really well. Always use new gaskets.

This should be plastered everywhere!!! I am part of a few FB groups and cooling system questions/issues come up nearly every day. Of course there routinely are the leaking head gasket responses...ugh!

My cooling system has been running perfectly, usually sitting below 200 degrees, since all my plastic parts were replaced with OEM Motorcraft.

 

[rgorke]

this is where the leak is dripping from. Everything above the Alternator and some below is bone dry. so the thermostat stuff and others were dry as well when i checked this morning.

Mine was leaking from above where you are pointing. It turned out to be the water pump. Again, make sure you are getting a Motorcraft!

 

[joegr]

this is where the leak is dripping from. Everything above the Alternator and some below is bone dry. so the thermostat stuff and others were dry as well when i checked this morning.
...

I still think that it is the plastics parts above, more likely than not. Still, I will also point out that the round thing that the oil filter is screwed onto is the oil-to-water cooler. It does have coolant circulating in it, but every time that I have heard about one of those leaking, it has been internally, into the engine oil, not external.

 

[ajv8]

valley hose can drip at the front connection

 

[Ryanthelsman]

Confirmed its leaking coolant. Probably obvious but at leased i found the specific fluid. And yes the DCCV was bone dry as well and to far away too be leaking where its placed. Soon im going too get my buddy and were going too drain the oil and cheak too see if the fluid have been mixng as i don't believe theres only oil in em. My friend thinks its the water pump and somthing to do with the weep holes. Hope its not since i have a tri cooler and id rather not have too take the entire front end apart… again.

(Will also be checking lines and the water oil once the oil filter is out and i can see*)

 

[Ryanthelsman]

Confirmed its leaking coolant. Probably obvious but at leased i found the specific fluid. And yes the DCCV was bone dry as well and to far away too be leaking where its placed. Soon im going too get my buddy and were going too drain the oil and cheak too see if the fluid have been mixng as i don't believe theres only oil in em. My friend thinks its the water pump and the

 

[milehighmikey]

Confirmed its leaking coolant. Probably obvious but at leased i found the specific fluid. And yes the DCCV was bone dry as well and to far away too be leaking where its placed. Soon im going too get my buddy and were going too drain the oil and cheak too see if the fluid have been mixng as i don't believe theres only oil in em. My friend thinks its the water pump and the

If you have water in the oil, the dipstick will surely indicate that. The oil will not look like oil, either dirty or new, it will look like coffee with lots of half and half.

 

[JustALs]

This should be plastered everywhere!!! I am part of a few FB groups and cooling system questions/issues come up nearly every day. Of course there routinely are the leaking head gasket responses...ugh!

My cooling system has been running perfectly, usually sitting below 200 degrees, since all my plastic parts were replaced with OEM Motorcraft.

not to jack the thread but yours run below 200? mine runs at 206ish, I also replaced most of my cooling system but still have the stock waterpump

 

[AmsterDutch]

not to jack the thread but yours run below 200? mine runs at 206ish, I also replaced most of my cooling system but still have the stock waterpump

FWIW...it's been well documented and everyone has came to the conclusion on the forum that the Lincoln LS runs a bit hotter than 200 degree F* I also replaced my entire coolant system... minus the radiator ( soon I will replace the radiator also) but the LS is fine running between 195- 215 IMO anything over 220 is a cause for concern

 

[04_Sport_LS]

Happened to be the crossover O-ring (design flaw) that pushes onto the elbow on top of the motor. Its very hard to see the leak without removing things and in between was dry also so I didnt believe it was leaking from the top.

Aftermarket o-ring is junk... just like the rest of the aftermarket parts.

The O-ring you are talking about... doesn't like to go into the backside of the T-stat housing dry.

Lubing the o-ring with a little coolant will help get the T-stat housing seat fully onto/into the elbow.

 

[04_Sport_LS]

Keep in mind also... that pretty much everything on the cooling system requires 89 inch pounds of torque.

When torqing a part in place... use a zig/zag pattern... instead of going in a circle. Torque everything twice... in the same sequence.

 

[ajv8]

just got stuck in traffic on a 101 degree day in my XJ8 with 220k miles. all original cooling system parts other than the thermostat tower and water pump. 208F max coolant temp with AC blasting.

my advice is use an OEM airtex water pump they’re not expensive.

 

[clubairth]

You still need to replace ALL the plastic cooling items as posted above. If you want to add the water pump to the list that's fine too.

joegr is correct again!
.
.
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[SHORod]

I'm surprised it's not been mentioned here yet, so maybe I missed something. But consider using a cooling system pressure tester to pressurize the cooling system to the cap pressure while you're ready to search for the leak. This hopefully will allow you to pinpoint the leak while the engine is cool and the fan and belt is not spinning or blowing coolant around. Your local auto parts store might have a pressure tester available for "rent" but otherwise they're not all that expensive for the convenience they bring, even if you only have to use it a couple of times.

-Rod

 

[joegr]

I'm surprised it's not been mentioned here yet, so maybe I missed something. But consider using a cooling system pressure tester to pressurize the cooling system to the cap pressure while you're ready to search for the leak. This hopefully will allow you to pinpoint the leak while the engine is cool and the fan and belt is not spinning or blowing coolant around. Your local auto parts store might have a pressure tester available for "rent" but otherwise they're not all that expensive for the convenience they bring, even if you only have to use it a couple of times.

-Rod

I used to think that too, till I had a mystery leak on my 04 LS (all new cooling system parts). It would not leak with the 16 PSI pressure test no matter what I did, hot, warm, cold, engine on, engine off, ... Maybe that is the rare exception, but it was my experience. (Leaked every time it was taken on the interstate.)

In the end, it was stopped by lightly sanding the ports on the front of the heads and putting tack seal on those two o-rings.

 

[SHORod]

Yep, no doubt there will be exceptions. Like the the dolphin-like noise on my Lincoln MKS that my ChassisEar suggests is loudest at the ABS HCU. However after replacing, reprogramming, and bleeding the HCU, the noise has not changed. The ChassisEar doesn't pick up the noise as loudly on anything else that I've found yet, as it does at the HCU. But, there have been enough other noises and rattles that I've found with the ChassisEar that I don't consider it a worthless tool. I sure would like the find the dolphin noise though!

-Rod

 

[milehighmikey]

Yep, no doubt there will be exceptions. Like the the dolphin-like noise on my Lincoln MKS that my ChassisEar suggests is loudest at the ABS HCU. However after replacing, reprogramming, and bleeding the HCU, the noise has not changed. The ChassisEar doesn't pick up the noise as loudly on anything else that I've found yet, as it does at the HCU. But, there have been enough other noises and rattles that I've found with the ChassisEar that I don't consider it a worthless tool. I sure would like the find the dolphin noise though!

-Rod

Huge ups for the chassis ears! One of the best mechanic assistance inventions ever!

 

[Buckie]

Im new to the forums but I own a 06 ls, i bought it about 5 months ago, im not sure if the setup is the same as yours. But mine was running hot like everyone talks about and i noticed fluid on top of the motor right under the intake and behind the thermostat housing but nothing had coolant on it that would indicate where it was coming from. So I waited til nightime warmed up the car and took a flashlight and started searching. What I found was at the top of the waterpump where it sets againt the motor it would randomly spit coolant from the gasket as it ran. The air coming off the belt would push the coolant away from the pump. Installed a new water pump and now it runs great. Even with all the problems with these cars and having to rebuild the tranny 3 weeks after I purchased it, I really enjoy my ls. Im gone do all I can to keep it up and running. Hope this helps.

 

[AmsterDutch]

Im new to the forums but I own a 06 ls, i bought it about 5 months ago, im not sure if the setup is the same as yours. But mine was running hot like everyone talks about and i noticed fluid on top of the motor right under the intake and behind the thermostat housing but nothing had coolant on it that would indicate where it was coming from. So I waited til nightime warmed up the car and took a flashlight and started searching. What I found was at the top of the waterpump where it sets againt the motor it would randomly spit coolant from the gasket as it ran. The air coming off the belt would push the coolant away from the pump. Installed a new water pump and now it runs great. Even with all the problems with these cars and having to rebuild the tranny 3 weeks after I purchased it, I really enjoy my ls. Im gone do all I can to keep it up and running. Hope this helps.

Agree, and just to add ...make sure the gasket is rubber and metal on the water pump...NO PAPER GASKET ON THE LS