Hate to beat a dead horse. (Overheating)

[CaddyFatStacks]

Hey guys, I know this topic has been beat to death but I believe I have a bit more of a complex overheating issue. 2000 Lincoln LS 3.0 is giving me some problems. I'm trying to get this car up and running properly for an elderly lady who needs it. I'm mechanically inclined but appartenly troubleshooting the cooling system is not my specialty. Its an intermittent overheating problem. Here is the work I've performed:

-Head gasket replacement (There was a broken piece leaking coolant that may have caused this, it has been replaced) the block was machined and tested good.
-Oil changed
-Ignition coils/plugs replaced (There were multiple coils bad and misfiring, changed all plugs)
-All fuel injectors ohmd out ( They all were within specs)
-PCV elbow replaced
-Cooling system was flushed and bleeded out
-Had shop do a block test as well as pressure test on cooling system (both passed)

I know some of these are unrelated to the overheating issue but I figured I'd put everything I did just incase something sticks out. This car can sit in the bay running for hours with no problem but as soon as it runs in city traffic it overheats within a few blocks. Like many others are experiencing the car cools down rapidly and is able to drive within a matter of minutes.

Yesterday I drove it around for about 30 minutes. I saw steam coming from under the hood near the degas bottle. I immediately pulled over as the temperture bar was rapidly moving towards overheating. I shut the engine off and quickly opened the hood to see coolant boiling in the degas bottle nearly escaping the pressure cap. Strangely seconds later the coolant was dropped. I'm not sure where it escaped from but I'm guessing thats where my problem is. I was able to top off the coolant shortly after but there was no leaks. I was able to drive it home (less than a mile) without any problems or leaks. Once it cooled down I removed the degas bottle and inspected it for cracks. I found nothing. Now I'm scratching my head. I thought maybe the head gasket cracked again but after reinstalling the degas bottle and bleeding the system again the car functions the same as before. No white smoke detected. I wanted to blame the hydraulic fan and its components but it appears to be functioning properly. And I'm sure that wouldn't cause the coolant to drop.

For what it's worth I heard the sound of a squealing serpintine belt shortly before seeing the steam coming from under the hood. When speaking with the lady she stated that she heard the same noise before the head gasket blew.

Anybody seen this happen before? My apologies for the lengthy story but hopefully the proof is in the details. This lady really needs this car and I would hate to let her down. Any ideas would be much appreciated.

 

[jjcool00]

From your description - this is just my opinion - it's either the upper radiator hose or the radiator. Although coolant can spray anywhere under the hood. This has been covered 1000's of times and you're situation is not any different. Overall all of the components need to be replaced but if you want to find the immediate culprit I'd check the upper radiator hose and the radiator side tanks. (Look for white residue). Both of these failed on me and I wasn't able to see them until I applied the accelerator and looked directly at the components in question.

 

[CaddyFatStacks]

Thanks for the quick response jjcool00. According to the owner, the radiator is only a couple years old but I won't rule that out as a possibility. I pressure washed around there yesterday so I could spot any new white residue. Nothing so far. Just out of curiosity, wouldn't the pressure test I had performed reveal any leaks?

 

[jjcool00]

Another thing I'd like to add is - cars don't just burn coolant so if the coolant level is decreasing there's a leak. You may not see coolant leaking but there's definitely a leak. It may burn off before you see it drip - depending on where it lands tho. When the coolant burns off it leaves a white residue - so look for that.

 

[jjcool00]

Thanks for the quick response jjcool00. According to the owner, the radiator is only a couple years old but I won't rule that out as a possibility. I pressure washed around there yesterday so I could spot any new white residue. Nothing so far. Just out of curiosity, wouldn't the pressure test I had performed reveal any leaks?

I've never performed a pressure test on my LS but from what I've read it is highly possible that your pressure test did not reveal leaks because they are most likely hairline fractures that require certain conditions to cause the leak (right amount of pressure, coolant temp, acceleration, etc.) Maybe someone else who has done this will chime in to correct me.

 

[joegr]

I've done pressure testing on an LS with a known coolant leak before. I tried various pressures (up to the 15 PSI relief limit), and I tried it with the engine cold, warm, and hot. I tried it with the engine running (from idle to 3K RPM) and with it off. In this particular case, not once could I make it leak on demand for me. However, I could go on a 30 minute test drive and find drops of coolant here and there when I got back. (All the plastic parts were new.) Until I experienced this, I believed that a pressure test would always show a leak, if you tried it at all temperatures. Now, I must admit that this is not true.

I did finally find it. In my case, it was where one of the rubber o-rings pressed against the engine block. There was a tiny bit of residue from the old seal still on the block. It wasn't all that close to where the drops of coolant were landing either.

As for the sudden drop in coolant level... One thing that I've seen is that an air (or sometimes steam) pocket will form in the engine, displacing coolant. When this pocket finally makes it to the degas bottle, the coolant in the bottle will rush into the engine to replace it, so the level very suddenly drops.

 

[1LoudLS]

I clicked on this thread expecting to see the same old sh!t,man I cant believe there is actually is a new overheating problem that hasn't been seen before!


with your specific conditions, I'm kinda leaning toward it having a problem with a leaking plastic part if you're sure that the fan is doing its job. when the one part was broke and leaking coolant that caused the head gasket problem, was just it replaced or were all of the other old brittle pieces of plastic replaced also?

 

[CaddyFatStacks]

1LoudLS I wasn't saying that my problem has never been seen before, I was merely stating that the solutions I found searching these forums have not been working for me. I replaced all the plastic components during the head gasket replacement. I'm changing out the water pump and thermostat tomorrow just to rule them out. I believe the water pump was the cause of the squealing serpentine belt I heard prior to the steam coming from under the hood. I'm thrown off by how the coolant went from practically puking out of the degas bottle, to being dropped from the system. Is there any high temp/high pressure checkpoints where the coolant would escape under such conditions? Since pressure washing I'm yet to find any new leaks or traces of a leak.

 

[1LoudLS]

I replaced all the plastic components during the head gasket replacement.

hey look at that, new information... probably should have added that to "work performed"...

Here is the work I've performed:

-Head gasket replacement (There was a broken piece leaking coolant that may have caused this, it has been replaced) the block was machined and tested good.
-Oil changed
-Ignition coils/plugs replaced (There were multiple coils bad and misfiring, changed all plugs)
-All fuel injectors ohmd out ( They all were within specs)
-PCV elbow replaced
-Cooling system was flushed and bleeded out
-Had shop do a block test as well as pressure test on cooling system (both passed)

no mention of replacing all of the plastic parts

is there any high temp/high pressure checkpoints where the coolant would escape under such conditions?

the degas cap is the pressure limiting device for the system. pressure gets too high, it relieves pressure. other than that, it should be sealed tight. so that steam either came from the cap or a leak somewhere you haven't found.

so then, you said you had boiling in the degas bottle, the right amount of pressure should not allow this to happen unless it was seriously hot. it really sounds to me like you have a leak somewhere. unless you have a coolant flowing problem because of the water pump or the thermostat, that would be where I would look

 

[joegr]

... you said you had boiling in the degas bottle, the right amount of pressure should not allow this to happen unless it was seriously hot. ...

What happens is that coolant boils in the engine, or air is sucked into the engine cooling loop through a leak. Then the engine air bleed line takes this air or steam to the degas bottle. It comes out the bottom of the metal tube that is inside the degas bottle, and bubbles to the surface. It makes people think that the coolant in the degas bottle itself is boiling, but that's not what's happening.

 

[Jim Henderson]

yeah finding a small leak on the LS is a pita.

Took me 6 months to figure out where on my radiator was leaking. After a long hot drive I would find a little bit of water on the radiator supports behind the radiator, so figured the leak must be there. Nope the leak was a hairline on the front of the tank, that is impossible to see on black plastic til it is big. I finally saw it when I heard a slight hiss and saw a tiny amount of water coming out of the front of the tank, more like bubbles.

Another leak I found by accident years back when the big plastic main water pipe(I even think that is what the manual calls it) on the front top of the engine also had a hairline crack, right in the casting seam, making it even harder to see the crack. Same thing no can see hairline crack on black plastic. But while I was dribbling water around the tstat housing, suddenly the water sprayed around when I got near the top of the water pipe. The invisible steam blew the water around and I was able to finally find the leak. Also I was occasionally able to hear the hiss but not see any steam, thus me trying the water dribble.

The LSV8 is just about the worst car I have owned as far as cooling system leaks and finding them. All this plastic develops cracks which are hard to see when active and which "seal up" when cool so you have to catch them while they're hot.

Good Luck,

Jim Henderson

 

[1LoudLS]

The LSV8 is just about the worst car I have owned as far as cooling system leaks and finding them. All this plastic develops cracks which are hard to see when active and which "seal up" when cool so you have to catch them while they're hot.

actually, once i figured out what was going on, finding the leak was pretty simple. and the black plastic actually makes it easier...

don't look for the leak or steam... when the coolant dries up, it leaves a white residue that is much easier to find, after replacing my cooling system, i actually found another leak starting that I didn't even know about, but clear as day the faint crack had white all around where it was.


even better, finding the leak really isnt really necessary, all the parts seem to have the same average life span, they all fail around the same time, so when one part springs a leak, its best to just replace them all at once. after doing the job you may think that you replaced something that you didn't need to, but you can bet that you would have had the same problem again in a month or two (if you're lucky), and that is if the other pieces don't break while taking some of them off to get to the one part that you're actually trying to replace

 

[CaddyFatStacks]

I've been busy during the holidays but I thought I should provide an update. I was able to locate a slight leak coming from the weep hole of the water pump. I replaced the water pump and thermostat. I thought I was lucky in fixing the problem but sure enough the car is still overheating intermittently. I noticed that after driving it around for a while there is some hesitation and the the needle starts creeping toward high temps. I'm starting to lean on a timing issue. I'm sure if I looked hard enough I could find a thread on how to set the timing. Can anyone provide a link by chance?

 

[joegr]

Ignition timing is not adjustable or settable. (Other than the use of some tuner tool such as SCT that alters PCM programming.)
Cam timing is not adjustable, but it is settable. Either you have it set correctly, or you should have bigger problems than overheating.