Wat ruik ik? Autogeuren verklaard

geurDe vrouwenneus is meestal vrij gevoelig voor geuren, vooral zwanger of rond de eisprong ruiken vrouwen beter dan normaal. Het overkomt mij wel eens dat ik in een auto stap en van alles ruik. Tegenwoordig vooral de nieuwgeur van allerlei (kunststof)materialen binnenin mijn CR-Z , maar in het verleden ook wel eens geuren die heel erg op iets anders lijken. Heb je alle mogelijke oorzaken – hond, sigaret, vuilnis, natte handdoek – geelimineerd en blijft het stinken, dan kun je natuurlijk gewoon zo’n afgrijslijk riekend en uitziend verfrisserding aan je binnenspiegel hangen – de ene vieze geur verbloemd de ander.  Maar je kunt ook serieus gaan zoeken waaraan het ligt. Nu ontdekte ik op de site van Popular Mechanics dit rijtje geuren die in de auto kunnen voorkomen en hun mogelijke betekenis. Interessant!


WHEN: After the engine has warmed or possibly even after it’s shut off for a few minutes.
THE CULPRIT: Coolant containing sweet-smelling (but toxic) ethylene glycol is leaking from somewhere. It could be coming from a radiator or heater hose, a failed intake manifold gasket or cylinder head. It might be coming from a leaky radiator cap or the radiator itself, especially if you smell it outside the car. A strong odor inside the passenger compartment probably means a bad heater core.

WHEN: You turn on the heater/air-conditioner fan and you get a whiff of that high-school gym locker.
THE CULPRIT: It’s good, old-fashioned mildew growing in the moisture condensing inside your a/c evaporator. And no, drizzling Listerine down the vents won’t fix it, in spite of what your brother-in-law read on the Internet. Check popularmechanics.com/musty for advice on curing this. Cheap solution: Turn off the a/c a mile from home and run the fan on high to dry the system out.


WHEN: All the time, especially after the vehicle has been sitting after a long drive.
THE CULPRIT: Yes, it really is brimstone, or, as it is usually called today, sulfur. This means gear lube is leaking from the manual transmission, transfer case or differential housing. Sulfur compounds in this oil serve as extreme-pressure lubricants for the gears, and can get pretty funky after a few years in service. Look for sulfury-smelling dribbles of viscous, oily stuff under the car. Unfortunately, leaks here typically mean a trip to the shop.

WHEN: Parked, especially inside a garage or when the weather is really warm.
THE CULPRIT: This is raw gasoline. On older cars–pre-1980 or so–some odor after a hot shutoff is normal from fuel afterboil in the carburetor float bowl. Modern cars have an evaporative-emissions system that’s tighter than our managing editor’s deadline schedule, so any fuel smell means something is wrong. There may be a leak from a fuel-injection line or a fuel-tank vent hose.


WHEN: Any time your engine is running.
THE CULPRIT: Hydrogen sulfide in the exhaust, which is produced by trace amounts of sulfur in gasoline. It’s supposed to be converted to sulfur dioxide in your catalytic converter. This may be indicative of a fuel-injection problem, and can be cured by a sharp mechanic. But often it means a failed catalytic converter. The bad news: A new cat is expensive. The good news is it’s probably covered under warranty. Check with your dealer.

WHEN: At all speeds, particularly when you’re working your way through the gears.
THE CULPRIT: The clutch facing is burning off as the clutch slips. The odor is reminiscent of smoldering newsprint: like trying to burn the Sunday newspaper all at once in the fireplace, especially if it’s been used to wrap sardines. The friction material is actually a paper composition, which explains the papery part of the smell. Either replace the clutch, or learn to stop riding the clutch pedal.


WHEN: Your engine is hot.
THE CULPRIT: Oil is leaking onto the hot exhaust manifold. This is an acrid, burning smell. It’s earthier and more nose-wrinkling than the odor of cooking oil used for french fries. If it’s from a leaky crankshaft seal that’s spraying oil all over, some of it will find the red-hot manifold–but most will be on the pavement. A leaky valve cover won’t necessarily leave a drip on the floor if all the oil drizzles onto the exhaust, vaporizing immediately. Look for smoke and try to stem the leak.

WHEN: After you’ve been using the brakes a lot, or hard, or both.
THE CULPRIT: The brake pads are overheated. This is perfectly normal after riding the brakes coming down a long mountain pass–but you should learn to downshift, you flatlander. If you smell this under normal driving conditions, you’ve got a dragging brake caused by a seized-up brake caliper piston. Or maybe you just left the handbrake on. Check the temperature of the brakes by hand–the hot one is probably the smelliest.

Ooit overigens een leuk artikel over Audi’s geurenteam geschreven, zie hier.

2 Comments on “Wat ruik ik? Autogeuren verklaard

  1. “Check the temperature of the brakes by hand–the hot one is probably the smelliest.”

    Of toch maar niet. Aan een vastgelopen rem kun je je poten flink branden.

  2. @haakie
    Hand tegen het (hart van het) wiel houden is al genoeg om te voelen of de rem heet is, dat scheelt weer een blaar 🙂

    Er gaat niks boven de geur die mijn oude Rx-7 verspreidt na een koude start: beetje onverbrande benzine gecombineerd met wat verbrande olie en een vleugje verbrande koelvloeistof. En dat is helemaal normaal 🙂

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