new oil cap = burning smell?

[1990LTD]

I installed a new oil fill cap because the old one wasn't really closing properly and could open too easily, but now I'm getting a slight l burning smell through the vents and outside of the car. No smoke and the cap looks okay but it's the only thing I've changed in the entire oil system. Went to install an oil pressure sender and adapter but my stupid power steering pump is in the way, so I put the original dummy light switch back in. Gotta buy a little elbow at the hardware store or something to angle it away, but that's beside the point (I think.)


I just got a generic replacement cap. I have absolutely no idea why it would cause me to smell burning. All of my fluids are good. and the cap SEEMS to seal okay. Oil/filter are new and clean and coolant is also brand new. PCV system is about 3-4k old and I don't see oil leaking anywhere - I assumed at first that some spilled on a manifold during the change and passed it off as nothing - but it's a day later and the smell is still there.


I replaced the radiator, hoses (upper/lower/bypass hose), thermostat and gasket, and water pump/gasket in the past few days - As well as the previously mentioned oil fill cap on the valve cover -Could any of those smell funky for the first few kilometers after installation? All of the parts were new except the reman Ford water pump.

[TxVic88]

did you keep the old cap? If so try swapping the new with the old cap.

Is it possible that you are leaking oil onto the exhaust manifolds at sides or rear of engine?

[86VickyLX]

Is the pipe behind the heads still attached? Check to see if there are any holes in the pipe. I've seen that before where there's a hole in it, and fumes are sucked in through the vent. Open the hood, rev the engine from under the hood, do you see smoke then? With a loud exhaust you won't here the tiny little exhaust leak from the pipe.

[1990LTD]

Is the pipe behind the heads still attached? Check to see if there are any holes in the pipe. I've seen that before where there's a hole in it, and fumes are sucked in through the vent. Open the hood, rev the engine from under the hood, do you see smoke then? With a loud exhaust you won't here the tiny little exhaust leak from the pipe.

Yeah, I've had the pipe running down to the cats clamped for a while and the pipe running from the check valve to the heads is sealed. I wouldn't be surprised if the sealed pipe leaked though, I'll investigate that.

[86VickyLX]

It's still there, it'll leak. The best way would be to plug the holes in the back of the heads, or use heads that don't have them to begin with.

[1990LTD]

Can I plug 'em while they're still on the car? New heads will be going on but not soon

[86VickyLX]

That I'm not too sure of. You might be able to if you take the upper intake off.
Btw, I think this is not because you got a new oil cap.

[85crownHPP]

Have you done the PVC trio on yours? If not, it could be the new seal on the cap is letting more crankcase pressure build up and spooge oily vapors out somewhere else, closer to exhaust.

[1990LTD]

pcv is new

[85crownHPP]

and the breather?

[1990LTD]

yep, it's all new. pcv valve, screen, rubber grommet dealie. hoses too.

[sly]

yes, you can plug the air injection ports without removing anything except the crossover pipe. what you'll need is some make gasket (high temp stuff), the bolts that hold the cross over pipe in... and some scrap plate steel to make "tabs" out of. You can also just cut the crossover pipe and swap sides with the parts that actually connect to the heads. put the make gasket on the flat part and bolt to the heads. hole sealed.

[1990LTD]

thanks slymer and everyone else

FWIW, it's most definitely exhaust. Going to see if I can wrestle my fat hands in there to fix the exhaust leak..using the old water pump backing plate for flat pieces to cover the hole when I bolt the little attachment piece back on. Some JB weld and swearing and it should be good to go. I'll pull out that combination valve as well since I have absolutely no need for it and I've been lazy about it so far.

[1990LTD]

jesus those exhaust manifolds are ugly. i sold the headers i had a while back because they weren't getting used and i needed the $..oh well, more money I will save on installation, haha

[1990LTD]

I found the crossover pipe in question, and removed the check valve/smog pump nonsense like I've been meaning to for ages. I removed those but the snow got worse by the time I got to the crossover pipe so I packed it in for the day. I see what I need to do for the smog ports on the heads but I don't think I can get at them without yanking the MAP sensor out of the way. Seems almost impossible to get leverage but it might be easier if the car were up on ramps...cursed winter.