temp gauge/ burning smelll when heat is on

[2000lincolnv8]

I have a 2000 LS V8 w/ 75K. I have been dealing w/ multiple issues for a few months now and I'm starting to think they are all related. First I got a CEL and had 2 coils replaced, valve cover gaskets (both sides), 8 boots and 8 plugs. Car was still shaking but no CEL and temp gauge would spike and I can smell buring (not quite sure if it's oil or rubber smell) when the heat is on. Took it back to the dealer and they replaced another coil and the shake issue is gone but they could not diagnose the smell issue (they double checked the valve cover work and said that everything is dry..no oil). I do not think that the engine is acutally overheating when the temp gauge spikes b/c it will go back down the normal levels once the car is shut off or on its own. My questions are...
What could cause the smell from the vents when the heat is on that could also make the car think it is overheating?
Could a valve cover gasket leak cause a P1299 code that I get when the engine temp goes up?
I really appreciate any help. I did search the site but can't seem to find a definative answer. Thanks.

[shorod]

According to the factory service manual, P1299 - Cylinder Head Over Temperature Protection Active. Chances are good that this is not actually a false indication, but you actually have a problem. When this occurs, the PCM will deactivate some cylinders and use them as a heat pump to help cool the engine down. When this occurs, you may experience decreased power and possibly the shaking that feels like a misfire.

Also per the service manual, this code is likely caused by:

• Engine cooling system concerns
• Low engine coolant level
• Base engine concerns

For starters, make sure your cooling system level is good and that the pressure cap holds pressure.

-Rod

[2000lincolnv8]

The coolant level is fine and there is pressure in the cap. I checked the paperwork from the previous owner and the temp gauge was replaced twice by the dealership, once at 45K and once at 55K. If the engine was overheating would it spike up then come right down so quickly?

[shorod]

I'll have to check the wiring diagrams for the Lincoln LS. Many times, the instrument panel guage uses a sending unit, and the PCM uses a similar coolant temperature sensor for temperature indication. If the LS is similar, the P1299 code would imply that both the coolant temperature sensor and coolant temperature sender are both reading similar temperatures. To have both malfunctioning along with the burning smell would be quite a coincidence. I would not be surprised though if the burning smell is residual oil from the leaking valve cover gaskets.

You might also want to investigate the water pump on yours. Fortunately, I don't have much familiarity with the cooling system on the LS (yet).

-Rod

[shorod]

I just checked the service manual for my 2004 LS V8. In 2004, a Cylinder Head Temperature sensor is used for the PCM and would direct the P1299 code. There is an Engine Coolant Temperature sender for the guage.

It appears there is a belt-driven water pump as well as an auxilliary electrical pump mounted to the radiator. I'm not sure that's the same set up as the 2000 model year though.

Have you verified that the cooling fan behind the radiator runs?

-Rod

[2000lincolnv8]

I can hear the fan click on when the temp gauge goes up so that is working. Sounds like I'll have to take it to the mechanic and check back. Thanks for the help.