Weird overheating problem

[MBertrand98]

hey guys I’ll get straight to the point here, my LS had been sitting for roughly a year, I start it up drive it around, and hit traffic and it started over heating, sounds normal right? But... when I rev the motor in neutral to 3k it goes back down to normal operating temp.... Any guesses? From what I can guess it’s either water pump or thermostat but from what I understand these cars aren’t as prone to water pump failure as it is thermostat? Anyone ever have this issue? Thanks in advance! (Fans hit all 3 speeds etc and I’ve tried the bleeding procedure for about 3 hours straight)

 

[grizzlyls]

Not a mechanic, but it seems odd reving it would cool it since its more explosive force. That said, I have just solved an issue that was random overheats and had to baby it in city traffic. Turns out it was the brand new OEM tstat replaced 6 months prior. Now that my mech replaced it with a 5 dollar Stant, zero problems through the Cali heat spell.

Would say for that cost, its worth starting with that.

 

[joegr]

So far, it sounds like it is the same old thing that hits them all (degraded plastic cooling system parts), but I'll play along.

If you really want help, then more information is needed.
V6 or V8?
Gen 1 (2000-2002) or gen 2 (2003-2006)?

What do you mean by "fans?" The LS has only one cooling fan. What other fan or fans are you talking about?
"Fans hit all three speeds" really confuses me. The engine cooling fan (hydraulic for gen 1, electric for gen 2) is a true variable speed design. While it is fully variable, it probably is more like 16 speeds or so, but still where does "3" come from? If you are talking about the AC blower, it too is way more than three speeds.

 

[grizzlyls]

I had given the benefit of the doubt that plastics had been replaced.

\/\/ Thanks joe, learnt sumthin about my hydraulics.

 

[joegr]

Not a mechanic, but it seems odd reving it would cool it since its more explosive force. ...

Higher speed would do one or two things.

For both gens, it would increase the amount of water flowing. If the system is air locked due to micro cracks in the plastic, it might be able to overcome that enough to cool it with no real load on the engine.

For the 1st gen, it could also increase the hydraulic fan speed in the case of a compromised but not failed system.

 

[joegr]

So, looks like he has a 2004, but still don't know if it is a V8 or a V6. I'm going to call it as plastics then. For the V8: GenII LS8 Cooling System Overhaul

(Yes, you need to do it all! It's very, very unlikely that you are an exception to all the rest of us.)

 

[MBertrand98]

Ah my bad guys, it’s a second gen 2004 V8, I believe the previous owner replaced the plastics a few years ago but it had been a few years, there’s no leaks that I can find

 

[joegr]

... there’s no leaks that I can find

Usually, you won't see them. Did you use the correct bleed procedure? 2006 Lincoln LS Workshop Manual
Did it seem to go correctly?
Did you get air out? (If you did, then how to you suppose it got in there?)
Did the previous owner use Motorcraft or Jaguar parts, or was it the Dorman parts? Did he really replace all of them? (Many try to skip the difficult one.)

 

[MBertrand98]

Usually, you won't see them. Did you use the correct bleed procedure? 2006 Lincoln LS Workshop Manual
Did it seem to go correctly?
Did you get air out? (If you did, then how to you suppose it got in there?)
Did the previous owner use Motorcraft or Jaguar parts, or was it the Dorman parts? Did he really replace all of them? (Many try to skip the difficult one.)

That’s a good question I’m not sure, just off the top of my head I think dorman, yep followed the procedure, one would think that an air bubble would eventually work its way up to the degas or bleed valve though right?

Do you think starting from scratch with a coolant flush would be a good place to start? I ordered a dccv so I’m going to have to open up the system anyway

 

[joegr]

If it's Dorman, then you have your answer. Most report problems (some very similar) when using the Dorman cooling parts. The Dorman degas doesn't hold pressure, and the Dorman thermostat + crossover apparently doesn't allow adequate coolant flow. Also, note that Dorman does not sell the 9N499 part, so that was probably not changed.

I expect that you have to do all this: GenII LS8 Cooling System Overhaul with the correct Motorcraft parts this time.