Check Engine Light, Smell 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.

 

[Quik LS]

P1299 Cylinder Head Overtemperature Protection Active

this means that the CHT really feels your car did overheat....

2000 models had a lot of issues with the thermostat - that's the first time I would try, which is a quick cheap job. It also forces you to drain and bleed the cooling system - which could be the other issue.

on the smell - how long ago on the VC gasket swap? it is very common to get oil onto the exhaust manifolds during the replacement. the smallest amount of oil will stink for a long time....

 

[SoonerLS]

P1299 is a cylinder head temp sensor detecting overheating. If the overheating is intermittent and goes away on its own, it could be because there's air in the system--you get a bubble of steam, which is "hotter" than the liquid coolant, at the temp sensor, which spikes the temp reading. Once it passes, things "cool" again, and the overheating episode is done.

One of the usual suspects in this condition is a bad coolant reservoir cap, or maybe a cracked reservoir bottle. The LS uses a pressurized coolant system, so when the reservoir cap starts going bad, it can't hold the pressure, which allows the steam bubbles to form. The cap is the cheapest/easiest fix.

As for the smell, it could still be oil. If they didn't clean the area really well, you could still have some oil there even though the leak has been repaired. It doesn't take much oil at all to make a really big stink...

 

[segxr7]

Sounds like a leaking heater core to me. Is the smell through the vents kind of a sweet maple syrup odor? Have you noticed any steam on your windshield?

That could also explain the temperature problems, because when you shut off the car, it would suck air in through the leak and leave an air pocket in the system.

 

[2000lincolnv8]

the smell does not seem to be sweet like coolant. thanks for the quick replies. the valve cover gasket job was done about 6 months ago and I just noticed the smell about 2 months ago once it got cold out and I started using the heat. I did, though, see occassional smoke out of the side of the engine (passenger side). I think that residual oil in the wells would have burnt off. Is there an internal gasket as well as an external one?

 

[beaups]

there are gaskets around each plug well and then a main (large) gasket that goes all the way around the valve cover. sounds like the dealer didn't do the job right and either pinched the main gasket or didn't torque the bolts down properly. Oil in the wells usually does not burn off (ever) as the valve covers don't get hot enough to burn oil. The main gasket would be the culprit as it allows oil to leak onto the exhaust manifold...which is definitely hot enough to burn oil.

As for overheat, that sounds like a separate issue and there is some great advice above...