Why is my LS overheating????

Justin S

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02 Ls 3.9 v8 was over heating. So I had a thermostat and flush done. Eventually saw that it leaked coolant, as long as i kept coolant in it, it wouldnt overheat. Leak got too bad to keep coolant in it so i replaced the degas bottle (Which was cracked) and both hoses going to it. i bled the system by the book. Still overheating if not overheating worse. I did a chemical block test on it, no combustion gas in coolant so it's not the head gasket. Im about to put in a new thermostat and housing and coolant flange and hoses. Any ideas? I'm seriously lost. I figured since it been hot since the new thermostat i should go ahead and replace it again. It takes about fifteen minutes exactly of driving to get hot. I will almost pay for help at this point.
 
02 Ls 3.9 v8 was over heating. So I had a thermostat and flush done. Eventually saw that it leaked coolant, as long as i kept coolant in it, it wouldnt overheat. Leak got too bad to keep coolant in it so i replaced the degas bottle (Which was cracked) and both hoses going to it. i bled the system by the book. Still overheating if not overheating worse. I did a chemical block test on it, no combustion gas in coolant so it's not the head gasket. Im about to put in a new thermostat and housing and coolant flange and hoses. Any ideas? I'm seriously lost. I figured since it been hot since the new thermostat i should go ahead and replace it again. It takes about fifteen minutes exactly of driving to get hot. I will almost pay for help at this point.
You need to replace the entire coolant system. There is a good bit of threads here about this same problem. You can't just replace one part at a time, these systems are made out of plastic parts. Also What brand did you use for your parts? OEM or Aftermarket?
 
It's been said at least a hundred times on this forum. This is nothing unusual. You have to replace ALL the plastic cooling system parts at once. You have at least the cross-over tube, and upper and lower radiator hoses left. You may also need to replace the radiator itself (side tanks are plastic and the passenger side one cracks at the top front).
You also must fill and bleed it exactly by this procedure: How to Drain the Lincoln LS Cooling System
 
Probably the same issue as the thousands of previous posts about overheating:
A. improper bleeding. There's an entire procedure
B. The thermostat itself is one of the most reliable parts
C. the plastic parts don't last very long in the cooling system. They rot from the inside out and crack. They're notorious for passing pressure tests. They start as just vapor/air leaks
D. If you keep losing coolant, you must have a leak

Plenty of knowledgeable people still here. Look at the post dates

Posting in multiple threads doesn't help. It's all the same people looking at the list. That leads to partial info and missing details
 
Okay I'll check radiator.
You need to replace the entire coolant system. There is a good bit of threads here about this same problem. You can't just replace one part at a time, these systems are made out of plastic parts. Also What brand did you use for your parts? OEM or Aftermarket?
All oem except the aluminum thermostat housing. And for the two guys who say I didnt bleed it right... Did you see where i said i bled it by the book? And it's not leaking anymore.. Obviously posting in different threads doesn't help if you dont read what i say. This is the stuff that makes it hard to find info. It's a battle of wits for whatever reason.
 
Okay I'll check radiator.

All oem except the aluminum thermostat housing. And for the two guys who say I didnt bleed it right... Did you see where i said i bled it by the book? And it's not leaking anymore.. Obviously posting in different threads doesn't help if you dont read what i say. This is the stuff that makes it hard to find info. It's a battle of wits for whatever reason.
Is the coolant boiling in the degas reservoir?
 
No. It's backing up into it but no bubbles. I let it cool down it goes back down.
 
No. It's backing up into it but no bubbles. I let it cool down it goes back down.
What do you mean backing up? The coolant will expand and/or fill up the degas reservoir as the engine produces more heat ...this is expected
 
What do you mean backing up? The coolant will expand and/or fill up the degas reservoir as the engine produces more heat ...this is expected

Also, there is actually some circulation of coolant through the degas bottle when the engine is running. Coolant comes in via the engine bleed hose (top of degas) and goes out via the return hose at the bottom of the degas.
 
It kept filling my bottle and getting air in my engine. I just replaced my thermostat and housing with jag s type aluminum one and my coolant flange with a new one and my hoses.. So far so good. Driving it as we speak. Ill let you kniw shortly if its okay. The coolant isnt backing up into the degas bottle now.
 
I believe ive fixed it! When i pulled the old flange off, the ends where the hose slips on, had the consistency of cardboard. And the same with the thermostat housing. Wow.. Why would they even put that material on a cooling system?
 
The remaining plastic parts are the same way. You'll be back very soon if they weren't all replaced.
 
I've replaced the bottle. It was cracked, I replaced t stat housing and flange, and hoses to tank and between flange and housing, what am i missing?
 
What ya think?

20190905_113847.jpg


20190905_113811.jpg
 
I got it off without pulling the intake too. Used a wrachet wrench with an elbow.
 
You didn't mention the cross over, but I see you did do that. You are missing the upper and lower radiator hoses, both have plastic sections.
 
Sorry for blowing up the feed but do you think my heater valve thing is going to be that bad? Thats the only other plastic i know of. Keep in mind I'm no certified mechanic
 
I have the upper hose just havent installed it. They both look good on the outside.. But i know that doesnt mean the inside is.
 
This is the thermostat i paid a shop over a hundred bucks to put in 6 months ago. I think i got ripped off.

20190905_114610.jpg
 
Sorry for blowing up the feed but do you think my heater valve thing is going to be that bad? Thats the only other plastic i know of. Keep in mind I'm no certified mechanic
You need to replace the whole system.. anything that has plastic. There is also a aux water pump and might want to consider replacing the main water pump. So yes you need to replace the heater valve as it is plastic but don't use aftermarket for any of the stuff you replace. The other remaining parts are at a higher risk of causing a leak now that the other stuff is new and not leaking. That is why everyone always says to replace the whole system. It's not that we are being jerks or anything like that it's just years of people experiencing the same problems with the same solution almost every time in this case. Also I can't stress enough to use OEM for the parts and especially for the heater valve. (I Think Bosch is OK as well in the heater valve case, as I am pretty sure that is who manufactured that for Ford as they are both stamped Bosch) Also The upgraded thermostat housing was very wise to do.
 
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Yes, ripped on the thermostat.
On the DCCV, I just wait for them to fail to replace them. One did fail such that it was leaking enough coolant that I had to replace the day I caught it.
So far, neither of my aux pumps have failed or leaked.
 
Yes, ripped on the thermostat.
On the DCCV, I just wait for them to fail to replace them. One did fail such that it was leaking enough coolant that I had to replace the day I caught it.
So far, neither of my aux pumps have failed or leaked.
The aux water pump on mine I went with aftermarket but only cause it was a new part and not reman and cause it was priced wrong at the time on amazon so I figured give it a shot and plus I still have my old one that was OEM that looked pretty good still. I think I paid like $12 shipped for a Cardone one that was brand new. Needless to say once I ordered it the price went up to over $200 so I got a steal on mine long as it does not cause any issues.
 
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There needs to be a sticky on these things, with a title "Overheat Fix" and an explanation on why the whole system needs to be done.

In Fact, a sticky for a bunch of stuff that fails on every LS would be great, and how to get the parts.
-No AC? Or Mixed air? DCCV -Sticky
-Overheat? Coolant replace - Sticky
-Interior trim clip fixes - Sticky
-Misfire? Ignition coils - Sticky

Edit: I know there is a sticky on a bunch of parts, but people don't notice it.
 
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I just dont get it.. Water pump is next i guess..
 

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