Useful Tips

The smell of exhaust gases in the car: what to check and how to eliminate


When an unpleasant odor appears inside the car, this is an obvious signal that the car should be carefully checked and diagnosed. After all, no one will argue with the fact that when the timing chain rattles or grinding brakes, you should take the car to the service. The situation is similar when the car starts to stink.

Here are seven common reasons why car odors can be unpleasant. Knowing the possible sources of unpleasant odor, you can quickly solve the problem, especially since an unpleasant odor is not so difficult to identify.

1. Faulty clutch or brake system

If the brake system or the clutch is worn, specific caustic odors can penetrate into the interior of the machine. A typical situation is driving with an activated parking brake lever or wedging a brake caliper on one of the wheels. The stench of a burnt clutch disc is very reminiscent of the smell of burning brake pads. There may be several reasons for burning the clutch disc. The clutch can slip due to wear and tear with significant mileage, or with incorrect adjustment. The pungent smell of burning brake pads or burnt clutch, as a rule, manifests itself when starting and braking, becoming especially noticeable when driving in urban traffic jams.

2. Problems of the radiator of the cooling system

An unusual sweetish smell usually appears when the cooling system is depressurized. Leaking radiator or cracked trunk hoses can cause antifreeze to leak from the system. The chemical composition of any antifreeze, including traditional domestic antifreeze, includes ethylene glycol - a substance with a sugary-sweet taste. The sweetness of antifreeze is especially noticeable when the coolant evaporates. And since any antifreeze flowing from the cooling system on a working car has a high temperature, the rate of evaporation of the liquid reaches its maximum performance.

First of all, a sweet smell will penetrate through the channels of the ventilation system of the passenger compartment - on a heated vehicle, air saturated with vapors of the coolant will flow from the deflectors to the passenger compartment. Another hint that indicates a radiator is leaking or other damage to the engine cooling system will be a slight but steady fogging of the windshield in the places of blowing. In this case, we are talking about condensate from the smallest drops of antifreeze that fall from the air ducts into the cabin and settle on the glass.

3. The musty smell of wet things

As already mentioned, a strip of fogging windshield in the area of ​​the vents of the ventilation system often indicates a malfunction of the cooling system. However, if the fogging of the windows is accompanied by the smell of musty, this is the main sign that water regularly enters the passenger compartment. A moldy odor in the interior of the car signals the ongoing process of decay. It is possible that one of the rubber seals of the door or trunk is damaged, or the window lifter mechanism of the side doors does not bring the glass to the stop. Moisture entering the interior of the car and accumulating on the floor impregnates the carpet, causing the formation of mold and an unpleasant odor.

A very similar musty smell can be caused by an excessively dirty air conditioner filter. The most noticeable stale or even rotten odor from the vents of the ventilation system will be when you turn on the air conditioner to blow the cabin in wet, rainy weather. Therefore, if mustiness in the cabin is manifested precisely after turning on the air conditioner, you should take care to change the in-cabin filter.

4. Oil leak

The appearance of a smell of burnt oil indicates leakage of oil. Motor or transmission oil, drops of which fall on the red-hot exhaust system, burning, form not only saturated gray smoke, but also cause a sharp smell of chemical combustion. Do not postpone the diagnosis of a car with such a symptom until later, because in addition to the unpleasant smell in the cabin, an oil leak is fraught with failure of the engine, which is subjected to oil starvation, as well as a harmful effect on the environment.

5. Damage to the catalyst

A catalytic converter designed to reduce the concentration of harmful emissions into the atmosphere after the combustion of automobile fuel is a rather complicated device, which is not so difficult to damage. Failure of the catalytic converter can lead to an extremely unpleasant smell of rotten eggs. The thing is that one of the main tasks of any catalytic converter is the capture of sulfur compounds, which are abundantly contained in the exhaust gases of cars. Failure of the converter leads to an incorrect process of filtering harmful substances, which causes the appearance of a sharp sulfuric smell in the cabin.
Sometimes an unpleasant smell of sulfur can also occur due to an untimely change of lubricating fluids. For example, there are cases when old oil in the transfer case of an SUV, starting to ooze out of the box, contributed to the appearance of a sharp smell of sulfur in the passenger compartment.

6. Gas leak

Perhaps the most dangerous source of unpleasant odor in a car is a damaged gas bottle or gas line in cars where gas is used as fuel. It is worth noting that for some older models of cars with a gas fuel system, a slight smell of gas that appears after starting the engine is the norm. However, if a characteristic odor appears in the interior of a new gas-fueled car, this should serve as an alarm to fully check the fuel system. There may be several reasons for the leak: a damaged fuel line, improper adjustment of the gas supply pressure level, clogged or damaged nozzles.

7. Products of biological decay

It may seem strange, but in almost half of cases the unpleasant smell in the car is caused not by technical reasons, but by banal rotting of food products. An ordinary vegetable or fruit that has fallen out of the bag when transporting food from the store can cause a terrible stench for a long time. This problem is most relevant in the summer months, when the interior of a closed car heats up very much, accelerating the decomposition processes. A very strong rotting smell comes from onions, mushrooms or potatoes. Not in the best way the air in the cabin will have accidentally spilled milk or yogurt by children.

Thus, before taking the car to a car service, you should make sure that under the chair or in the far corner of the trunk did not roll raw potatoes or mushrooms after transporting the products.

Find out the reasons

One of the culprits of such an unpleasant incident as the smell of exhaust gases in the car interior is a polluted cabin filter. It is located behind the glove compartment, dismantling which you can verify its cleanliness or the need for replacement. What if the filter is clean?

  1. The broken tightness of the exhaust system results in unpleasant “aromas”. It's all about laying the exhaust pipe: it can be damaged during movement.
  2. Also, the transmission of gases into the machine occurs due to defects in the exhaust manifold.
  3. The burnout of the corrugation allows the exhaust to enter the cabin with the windows closed. You can diagnose such moments by hearing the amplified noise of the motor.

The way out is repair to restore the tightness of the system.

The secrets of sealing gum

Most often, worn out rubber bands are to blame for the appearance of an exhaust odor in the passenger compartment. During the trip, the cabin pressure is reduced compared to atmospheric values. This is due to the fact that air enters due to the operation of the heater and exits through the valves. With a decrease in pressure indicators, air flows are sent to the cabin.

The rubber bands on the doors and rear lights dry out, crack and allow the exhaust to enter the car unhindered. Replacing elastic bands is the only right decision.

A couple of tips for repairing a silencer clamp

The exhaust system is of great importance for comfortable driving: it reduces engine noise, removes smoky formations. Often the muffler clamp is damaged in the design, a malfunction of which can cause, in addition to air damage in the cabin, an increase in the temperature of the gases escaping from the cylinders. Failure of this part leads to depressurization of the entire system. The most difficult thing is when this trouble happened directly on the road. It is far from a car service, and it is impossible to ride with a damaged clamp.

The best advice if there is a smell of exhaust gases in the passenger compartment is to have cold welding in the glove compartment. The adhesive easily glues metal parts, transferring high temperatures and increased loads. The damaged area is cleaned of rust and carbon deposits, glue is applied. It is important to do this with gloves on. After the procedure, you need to wait 1 hour and move on.

You can use ceramic tape moistened with water. The tape is repeatedly wrapped around a defective place. Some use sealant. It needs to wait about half an hour to dry.

Diagnostic measures

How can the driver understand the causes of problems with the device exhaust system of the car on their own?

  • It is necessary to check the tightness of the pipes, rocker boot. Do not advise touching the pipes with your hands - they have a high temperature during operation of the power unit. You can verify the leak by running your hand through the air.
  • Sometimes it does not hurt to look into the trunk. Seals in station wagons, hatchbacks suffer from wear more often than other car brands. Checking ventilation with check valves will give a positive result.
  • In old cars, it is recommended to remove the plastic luggage "pocket". The transport rusts, the holes obtained during operation are another reason for the appearance of the smell of exhaust gases in the cabin and the elimination of this trouble.

You can fix the seals on the rear windows with the help of liquid nails glue. Sometimes the car starts to smell like rotten eggs. What is it?

Elimination of a special "flavor"

Exhaust gases may smell different and the above odor signals a hydrogen sulfide leak. So, it's time to do the catalytic converter. The designers came up with an aggregate to reduce the accumulation of harmful substances during engine operation. Low-quality fuel provokes damage to the device. Driving with a damaged device will increase fuel consumption significantly. Flushing and installing a snag will help eliminate the problem. Flushing measures are justified when the resistance to exhaust gases is increased. In a breakdown situation, this will not work.

The lambda probe, which deceives the electronics, is placed in a trick, a metal device, but this gives a chance to get to the nearest car service to repair the catalyst. Replacement will cost a lot, therefore it is important to control all the nodes and mechanisms of the “swallow”, to visit SRT on time for diagnosis and maintenance.

It often smells of gasoline due to a gas tank leak, you should not be lazy and often look into this device. Sweet "flavor" will tell about the leak of antifreeze. It is recommended to inspect the radiator and hoses of the cooling system. The "engine" eventually overheats, fuel consumption palpable for the driver’s wallet. Careful attitude to the vehicle will help not to “miss” serious malfunctions and save from large material costs for repairs.

Why does it smell in the car

First of all, to understand how to cope with the "enemy", you need to find the cause of the unpleasant "amber." Possible options due to which the car may smell bad:

  • You and your passengers smoked in the car for a long time.
  • Pets were transported, which, in addition to having a certain smell themselves, could also be frightened of something and “go by themselves”.
  • In the cabin there was a meal. At the same time, no one is safe from accidentally dropping a piece of sandwich or spilling any drink on the upholstery. Then, over time, the “yummy” that has fallen under the seat once begins to rot and exude a fetid odor.

  • Rodents climbed into the salon, for example, mice, and there they "died the death of the brave." Naturally, a cadaverous smell will come from them, which even eats into metal.
  • Wet seat upholstery also does not contribute to pleasant odors. The problem is especially relevant in the winter, when it is quite difficult to carry out airing. Moisture accumulates in them, and the smell is felt more and more.
  • Forgotten in the glove compartment is dirty, that is, simply not washed clothes. After a certain time, it will begin to exude a rather unpleasant, musty smell.
  • Ineffective ventilation and air conditioning.
  • After a shopping trip for groceries, you just forgot something in the car (it doesn’t matter in the cabin or in the trunk). And only when you start to smell a nasty smell, you “remember everything”, but “the job has already been done” and the source must be eliminated.
  • Sweat and dust.
  • The smell of gasoline and other "troubles" indicating the technical malfunctions of your vehicle (we will explain their causes in the sections below).

Why does the car smell of gasoline

What is the reason:

  • Malfunction of the fuel pump (wear gaskets, cracks in the hoses and so on).
  • Badly twisted spark plugs.
  • Perforation (i.e., holes) in the fuel tank.
  • Weak crimp clamps on the fuel hoses and the presence of cracks in them.
  • Depressurization of the gas tank.

Important! You can conduct a visual inspection of your car yourself or do it in a car service with professionals. If gaskets of a fuel pump, spark plugs, fuel hoses and o-rings of a gas tank cover will change regularly, then you will be able to avoid the above problems in the future.

Causes of interior odors related to vehicle technical problems

There are smells of another category, signaling about those or other malfunctions of your "steel horse":

  • A musty smell indicates certain malfunctions in the climate control. Most likely, the system is dirty. You may need to disassemble the air filter and air conditioner, as well as clean them mechanically.
  • The sweet smell that occurs when the interior heating system is operating indicates leaks in the pipes or the radiator itself.

Preventive measures to eliminate the unpleasant "amber" in the car

Depending on the cause of the smell and the measures to eliminate it, they will also be different (the main thing is that they no longer arise in the future). So what we do:

  • Do not drink or eat in the car.

  • We don’t smoke ourselves and we don’t allow others to do it.
  • We do not allow a mess not only in the cabin, but also in the trunk.
  • We try not to carry animals. If we do this, we take all precautions to eliminate unpleasant consequences.
  • We periodically dry the vehicle: in the summer - naturally, and in the winter using special devices.
  • After each visit to the supermarket, we check the vehicle for abandoned products that will begin to deteriorate after a couple of days and exhale an unpleasant odor.

We continue to fight odors

If certain measures have already been taken, but the smell is still present: what else can be done:

  • We put in order the air conditioner (for example, using the antiseptic Chlorhexidine) and the ventilation system.

On a note! We recommend replacing the cabin filter after 20,000 ÷ 25,000 kilometers (or once a year).

  • We use flavors and aerosols for special purposes, which can be purchased in the distribution network, in particular the “dry fog” preparation.
  • Periodically clean the interior of your car.

  • We use household chemicals of an organic nature. We simply spray them and rub them into the fabric trim of the seats, as well as seat belts, floor mats and door trim.
  • We produce ozonation of the vehicle interior in a car service. This procedure is also called oxygen purification.
  • We fight odors using vinegar, soda, activated carbon and ammonia.
  • We use folk remedies.

Let us dwell on some points in more detail.

The drug "dry fog"

Today, this technology is the most advanced. Its main task is to completely neutralize the aromas that have arisen. Before you start the process, you need to determine the aroma that you prefer. Most often, motorists choose the smell of citrus fruits, for example, orange or mandarin.

Within 2–3 minutes we spray the selected preparation around the cabin, then close it, wait about one hour, open and ventilate, carefully removing condensate formations from all the elements inside.

Important! Подобный препарат не оставляет каких-либо следов. It is important. Аромат же сохраняется в течение 1÷1,5месяцев.


Когда бактерии и микроорганизмы пропитали обивку салона, то удалить эти запахи из транспортного средства можно исключительно с помощью такой эффективной технологии, как озонирование. Today this service, which can be obtained at a car service center, is gaining more and more popularity (despite its relative high cost).

What is the principle of this procedure? Ozone, which is a powerful oxidizing agent, is able to penetrate into the thickness of virtually any material and fight both bacteria and fungi, as well as mold.

On a note! Unlike many methods that only mask the smell and make it more “light”, this method is different in that it allows you to completely remove it.

The procedure is performed as follows:

  • An oxygen cylinder (that is, an ozone generator) is placed in the cabin.

  • Turn on the ventilation system in recirculation mode.
  • After 20 minutes, the ventilation is turned off, and the ozone generator continues to work for 15 minutes.
  • The vehicle is ventilated and wet-cleaned in the cabin.

On a note! For some time after the procedure, the smell of ozone persists in the car, but it has a rather pleasant aroma and does not pose any threat to the health of not only people, but also animals.

Vinegar can also help

We use the ability of acetic acid to react with other substances, while neutralizing them. We leave a can with table vinegar (80 ÷ 100 ml) on the mat inside the car for the night, and aerate in the morning. We repeat the procedure for a week, each time putting a new portion, and you will no longer be upset by the unpleasant smell.

On a note! Remember: after 20 ÷ 25 hours, the adsorbing properties of vinegar decline.

Folk odor control

We offer simple ways to get rid of the unpleasant "amber":

  • We apply a few drops of such a powerful flavoring as vanilla extract on the seat upholstery.
  • We divide the vanilla pods in half, put the contents of each half on a cotton swab and place them somewhere in the cabin. Such a flavoring agent is valid for 7-8 days.

Important! Do not use synthetic vanilla: there is no use in it.

  • We place the coffee grounds in a container and leave, for example, on the front panel, at night. In the morning, we air the interior.
  • Mix ground cinnamon with apple cider vinegar to make a thick paste. We place the resulting mixture in a plastic container (always with a lid), in which holes are made from above. We put all this in the car interior, for example, under the driver's seat, and enjoy the aromas.
  • Put dried crushed citrus zest on the bottom of the canvas bag and hang them somewhere in the cabin. Women will appreciate this fragrance.
  • We take a large green apple, cut out the core from it and leave the fruit to dry completely in the cabin. Further, it acts as an adsorbent.
  • Coffee beans can also help deal with the problem of odors. Unlike coffee grounds, they “like” sunlight. Grains can be placed in canvas bags, in containers, or simply on a piece of paper.

Important! The presence of a pleasant aroma in the interior of the car, of course, is very important, but we should not forget that not all of them contribute to the concentration of the driver. Remember: the smell of fresh pastries or grass, as well as flowers can lead to carelessness, and this on the road is fraught with serious consequences.

Driving in a car with odors is unpleasant and unsafe. Methods of elimination depend on a source, and there can be a lot of them.

The car interior is a ventilated space, but enclosed. Smells in it linger willingly and can carry a serious threat to movement. Try to be attentive and focused if your head breaks or the whole body is aggravated by an abnormal aroma!

The most dangerous is the smell of gasoline. This is a signal about a leak in the fuel system. Remember how the components of the exhaust system are heated, and immediately send the car for diagnosis to the service. Preferably on a tow truck. The exhaust runs along almost the entire length of the car, so leakage is equally dangerous both under the hood and around the fuel tank.

You can not worry only if you yourself have put a canister in the trunk. It will not cause a fire, but if it leaks onto the carpet, only dry cleaning will remove the smell.

Oil is not as dangerous as gasoline, but it smells no less nasty. It is, of course, about burnt grease falling on the hot components of the exhaust. Here diagnostics should be taken care of, if not because of a possible fire, then at least because of the risk of blinking the oil level and getting into an expensive engine repair. Dripping oil is already a “crime” compared to light oil misting on a motor, which even fresh cars often sin.

The smell of singing clutch appears immediately after a wheel slip or a very severe mistake when shifting gears. The logical chain is very simple, so even novice drivers will determine the source of an unpleasant “amber”. It passes quickly, so there is no need to worry. If the odor persists throughout the trip, check the clutch for proper functioning and proper adjustment.

Modern brake systems - disc, with ABS and ESP - are effective and should not smell during normal operation. Otherwise, the wedged brake shoe is probably the source of burning odor. There are several diagnostic methods. The easiest way is to determine the degree of heating of the brake discs by hand after the trip. But by no means putting a finger on them! Even the mechanism that worked in normal mode will easily leave a burn - for this it is enough to bring your hand to a close distance. If one of the disks is noticeably hotter than the others, something is wrong with it.

Next in terms of complexity are two more ways. Jack the car and rotate each wheel in turn. The sound and the degree of resistance will tell you which of the calipers is the problem. An even more time-consuming method: remove each wheel and evaluate the thickness of the brake pads. Excessive wear on one of the mechanisms or on the one hand is a sign of a problem.

The sweet smell of antifreeze is difficult to confuse with something: in the car he is the only one. Due to the "family ties" of cooling and heating systems, leakage quickly becomes known to the inhabitants of the cabin. Not only by smell, but also by lightly fogging the windshield near the airflow deflector. Another sure indicator is the level of coolant in the expansion tank. His fall indicates an emergency.

Getting on the hot release and brakes, anti-icing chemistry can give such a smell that you want to leave the car in the nearest parking lot. Fortunately, this does not happen with every roster. Tip one: endure or not ride in the winter.

Air conditioning

Air conditioning or climate control requires regular maintenance. You can, of course, pull to the last. The musty smell when you turn on the cooling mode will quickly remind you that it is time for a service to antibacterial treatment of the air conditioning system. Delaying with it, by the way, is fraught with diseases for the driver and passengers: the bowels of the system eventually become a hotbed of fungi and bacteria.

Do not forget about the timely replacement of the cabin filter. It can smell from him. Although, as a rule, 15,000 km, this element is able to depart even in the conditions of the Russian metropolis.

Dampness in the passenger compartment is accumulated in the floor carpet. This is a common situation for our winter: getting into a car in perfectly dry shoes, alas, is impossible. And yet, if you are not too lazy to shake off your shoes, it is unlikely to grow into a critical situation. It is enough to pour the accumulated water from the rubber mats or dry the pile.

The problem may be deeper. Clogged drainage under the hood or from the sunroof leaves water one way - to the salon floor, under the carpet. We recently encountered this situation at the editorial West. Drying the floor carpet in this case will have to be thorough. Perhaps even with removal from the car.

Smoky interior - a common phenomenon. To hammer in the smell of tobacco, which is ingrained in plastic and fabric, is a thankless task. Perhaps you will facilitate the existence inside the machine, but the source of the “aroma” will remain. Here you can recommend only large-scale dry cleaning of the cabin. If you feel sorry for the money to visit professionals, devote this weekend to the cottage. Buying cleaning products will cost a little cheaper, and the result is likely to be not 100%, but also noticeable.

The most obvious source of a sudden smell, of a “non-automobile" origin is garbage. For example, open or half-eaten foods forgotten in the back seat. Look for rotting or mold in pockets in the upholstery, under the front seats, in the nooks of the trunk.

This is exactly the case when a cheap fragrance from a car shop is a suitable option. Remove the source of the smell, and its remnants will soon disappear on their own. Until then, the primitive Christmas tree on the mirror will brighten up your existence in the car.