glasat111

Two days ago, I had my trusted service garage change the oil on my '07 ES350, as he's often done. It was time, based on the oil maintenance light notification. When I drove it in, there was nothing wrong with the car, period. On leaving after the oil change, I noticed a light burning oil odor, seemingly coming from the vents. I'd hoped this was just some spilled oil on a pipe and would soon burn off....but I took the car back today, just to have them look it over, as it was still happening. They test drove it (without me) and smelled nothing, but said they found some excess oil and cleaned it (who knows if this was said just to placate me, but that's not their style). They believed that any residual oil was done...or nearly done.....burning off, by today.

I now think the reason they didn't smell any oil was possibly that, when I gave them the car, the climate system was Off and likely would have so remained, during their test drive (we'd had moderately cold weather here in FL and I've since realized I'd not been using the A/C much, over these two days). Leaving the garage today, I had to agree the smell seemed gone, and the climate system, as I only later today realized, was still off. Later today, it'd warmed enough that I ran the A/C and then oil odor became immediately noticeable, quite strong. I then did a lot of comparison "testing" of settings and here's what I've noticed, in summary:

1) If the climate control is completely off and air flow is set to outside/refresh as usual, there is no odor.
2) If the climate control is off but the fan is on, there is still no odor.
3) If the A/C or heat is on, there is odor. The odor seems to be stronger on "A/C" than on Heat, but that may just be subjective.
4) Any odor present is noticeable primarily (or only?) with the car stopped at a light, and doesn't seem noticeable while moving, presumably due to air flow around the car and/or any potential source like a drip while stopped(?).

Again, there were no signs of any problems when I handed over my cars at the garage. They DID also rotate my tires, btw, just in case that inspires any thinking outside of the box, on here. They also routinely change the cabin filter but I can't say how many miles back that was last done. Today is Friday...I now have have an appointment for this coming Monday, to hopefully nail this down. The shop owner today wondered on the phone whether I may need a new A/C compressor....but, all was well at the time of the oil change and it's not like him to try gouging for an unnecessary part. Or, maybe his mechanic messed something up during the change and, today when I'd taken it back, they didn't catch this? Problem with PCV....or a loose/damaged hose? Please don't tell me it's the A/C compressor! They'd replaced it only a few(?) years ago, at most. Thank you.

ellocovg

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glasat111

Thank U for replying, ellocovg. Are you suggesting changing the "cabin air filter," then? I sure hope your idea is the answer, vs the shop owner's initial phone thought, that I might need a new A/C compressor(!!). I should have initially noted also that there is no sign of oil leakage, as such....nothing dripping on the driveway and the oil cap is clean and tight. (Topside, the entire visible engine and plastic shield are spotless.) If there IS somehow a problem with the A/C compressor, it is awfully hard to believe it'd coincidentally(?) suddenly started just minutes after my oil change....and there'd been NO problems of any kind, before this service. Anyone else have further thoughts, please?

jagtoes

2 things I can think of that happen during an oil change. The 1st being that the oil filter is next to the exhaust pipe the technician spilled or wiped oil on this pipe and it is burning off. The second is they spilled oil while filling the engine. This runs down the the front of the motor and is very difficult to clean up. You would not be able to see this as the plastic engine cover would cover this up. Any oil smell gets drawn into the HVAC vents so it gets trapped in the system. I do find it funny that you don't get the smell with the system on or off. I think the fan speed would increase the smell.

glasat111

Hi & thanks, jagtoes. Yes, it seems odd to not smell oil when only the venting fan is on (no A/C or heat) or when the entire climate system is Off, but I'm only a layman. If the A/C compressor IS okay, could there still be any reason to get the odor only when the A/C (or heat) is running? Scratching my head.

Second: your thought about oil running down the front of the motor is interesting. There's been no spillage onto the ground at home, since Wednesday, but maybe not a lot of oil would be involved? Would THIS oil "down front" likely eventually burn off? I can live with the smell (although I've read it's not healthy), if I know it'll go away on its own. Or, would it, if it's "trapped" in the vents? I sure don't like that word, "trapped."

Also, there IS a Lexus dealer in my area, as a last resort....but I'm loathe to make their boat payments.

jagtoes

By turning on the auto HVAC system you turn on the fan at the radiator (if AC on) and also the fans in the HVAC system. This would push the air through the system whereas with the system off there is little fan speed to push the air. As for spillage in the front of the engine it will not burn away but eventually collect dust and dirt which will cover the smell. Try taking the car to a car wash and get the under carriage washed . Also remove the plastic engine cover and look underneath. It pulls right off.

glasat111

Okay....I'll take a look around the engine and thanks. Still unsure whether you'd meant earlier that there is actual motor oil somewhere IN my vent(s)....as opposed to the vents carrying the odor of oil spilled (say) down the engine's front.

jagtoes

Sorry if you misunderstood. I don't believe there is any oil in your vents. It is oil spilled somewhere in the engine compartment and the fumes are being drawn into the air inlet to the HVAC system.

glasat111

That is good news, indeed, jagtoes...thank you. So, maybe the "worst" thing here is the oil needs to be cleaned from (perhaps) the engine front, by a good (power?) wash or such, and eventually the fumes will dissipate from the HVAC system. Let me ask: IF the A/C compressor has actually developed a problem (by some bizarre coincidence of happening at the same time I'd had a simple oil change), COULD it cause an odor...not necessarily even of "burning oil"...thru the system, when active? The odor smells more like burnt oil than, say, like a belt heating up due to a frozen pulley. Thank you.

jagtoes

There is to much speculation going on here. You need to have someone besides the guy that changed your oil look into this.

glasat111

Well said and thanks again for your time & thoughts, jagtoes. Will do.