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Car Forum / Toyota / Camry / March 2005scent of a motor
97 Camry 4, 104K miles. With the heater on and fan running there is a faint odor of exhaust when sitting still. This odor is unnoticeable when moving. I have suspected vehicles in front of me emitting fumes that are sucked in by the fresh air cowling, but it makes no difference whether I am behind someone or completely alone. On Monday I had the car at the dealer for annual safety inspection and mentioned the odor. The mechanic said I had no exhaust leaks since it would be heard rather than smelled. I have not noticed any leaks or radiator fluid loss. There is no smoke emitted from the engine compartment. Is there anything else to check other than my head?  SignatureNo matter what happens, someone will find a way to take it too seriously. > 97 Camry 4, 104K miles. > [quoted text clipped - 11 lines] > smoke emitted from the engine compartment. Is there anything else to > check other than my head? The mechanic is wrong. Some exhaust leaks cannot be heard due to position of leak, strength of leak, insulation, engine noise and etc. If it is migrating into the cabin this can be lethal if breathed for a prolonged period. With engine running have someone put a rag over the end of the exhaust while you listen along the length of the vehicle. On a lift is best if you have access to one. Many undetectable leaks will make a loud enough sound due to the increased exhaust pressure to be heard. HTH, davidj92 Do you have a home Co detector with digital display and battery backup, put it in the car. Or plug it in and let the car idle. It may not be high enough to alarm but will register and record any Co level if it is digital display with Peak Co memory. Then you will know. Nighthawk apx 35$ But some models alarm without 120vac even thought they operate. > 97 Camry 4, 104K miles. > [quoted text clipped - 11 lines] > emitted from the engine compartment. Is there anything else to check > other than my head? Apart from straight exhaust smells, there is another type and cause which occurs in engines which are generating too much blow-by due compression-ring wear. The PCV system usually causes blow-by fumes to be reburned by sucking them back into the inlet. If the BB is getting out and is being sucked into the car's AC air intake, the smell has a distinctly 'fuel' type odor. Jason >> 97 Camry 4, 104K miles. >> [quoted text clipped - 21 lines] > > Jason Two part test Question: A) In a "closed type" ventilation system, if the PCV's flow is less than the volume of vapor escaping the crankcase, the excess vapor goes .... where? B) From the breather pipe juntion (located between the air filter and the throttle body), how can this excess crankcase vapor excape into the air for you to smell? Signature- Philip > >> 97 Camry 4, 104K miles. > >> [quoted text clipped - 27 lines] > between the air filter and the throttle body), how can this excess crankcase > vapor excape into the air for you to smell? Yes Phil,.....but I said, "if the BB (excessive fumes due wear) is getting out" Have you seen the inside of an engine bay with a badly fuming motor with an enclosed PCV system, after its been cruising at motorway speed? What did you observe? Jason >>>> 97 Camry 4, 104K miles. >>>> [quoted text clipped - 38 lines] > > Jason Even with a plugged PCV, the blowby gases cannot get out into the atmosphere with a closed system. You would have plug off the PCV and pull the breather hose from the air box to witness blow-by fumes. Now, I have an old diesel with a road draft tube and no PCV valve at all. You bet you can see blowby especially after climbing up a few thousand feet in altitude at nearly full throttle. Signature- Philip > >>>> 97 Camry 4, 104K miles. > >>>> [quoted text clipped - 42 lines] > with a closed system. You would have plug off the PCV and pull the breather > hose from the air box to witness blow-by fumes. The PCV valve has a spring loaded plunger which limits how much BB and air that can be admitted to the manifold. At idle the man-vac is greatest but airflow is lowest, so the PCV only allows a small amt of scavenging otherwise the engine would stall (lean). At medium throttle the valve sits midway allowing greatest scavenging. At full-throttle when man-vac (or negative pressure) is highest, the valve is almost closed again by design. Not sure why they are designed this way? At high throttle the breather tube (connected between the air- filter and TBody) has to take most of the BB and if the engine is worn, oil will collect in the area where the breather accesses the air-intake. This was particularly obvious in cars which had the breather accessing the air-filter box. My point was, if the engine breather tube is split or popped off, a lot of that BB at high-peddling will leak out into the engine bay. After some time, you can see oil wetness where this is occuring. > Now, I have an old diesel with a road draft tube and no PCV valve at all. > You bet you can see blowby especially after climbing up a few thousand feet > in altitude at nearly full throttle. Yes, even for 10 secs or so after the engine has idled down. The crankcase takes time to vent the built-up BB out the draft-tube. Jason >>>>> 97 Camry 4, 104K miles. >>>>> [quoted text clipped - 46 lines] > You bet you can see blowby especially after climbing up a few thousand feet > in altitude at nearly full throttle. I always wondered what kept you running so long! ;) > Apart from straight exhaust smells, there is another type and cause > which occurs in engines which are generating too much blow-by due [quoted text clipped - 4 lines] > > Jason I doubt the PCV valve has ever been replaced. Do you think this may be the culprit? When you say compression-ring, is that the piston rings? This car had an engine overhaul around 60K miles and that was one of the things replaced. SignatureNo matter what happens someone will find a way to take it too seriously. > > Apart from straight exhaust smells, there is another type and cause > > which occurs in engines which are generating too much blow-by due [quoted text clipped - 7 lines] > I doubt the PCV valve has ever been replaced. Do you think this may be > the culprit? Only if the engine is also fuming excessively. > When you say compression-ring, is that the piston rings? Yep. This car had > an engine overhaul around 60K miles and that was one of the things > replaced. If the engine was overhauled, then BB is not likely to be the cause. Jason How about distributor O ring failure and a light miss of oil being thrown up and burnt and smell being sucked into the ventilation. Look at the underside of the hood for oil residue. > 97 Camry 4, 104K miles. > [quoted text clipped - 11 lines] > emitted from the engine compartment. Is there anything else to check > other than my head? > How about distributor O ring failure and a light miss of oil being > thrown up and burnt and smell being sucked into the ventilation. > Look at the underside of the hood for oil residue. I may be wrong, but I don't think this vehicle has a distributor. Is that possible? SignatureNo matter what happens someone will find a way to take it too seriously. Your initial posting mentioned the odor of exhaust - that is not the odor of burning oil, or engine blow by gases. The exhaust system is fairly straghtforward. The service manual includes maintenance items for checking the torque of the fasteners in the exhaust system - often overlooked I suspect. Presumably they list checking fasteners because the repeated heating and cooling expands and contracts the metals. There is a flexible section near the front, that allows for engine movement under load that seems to cause problems fairly often. Other than that, there are just a few junctions in the pipes where sections connect, and the mufflers / resonators / catalytic converters / pipes - need to be checked for pinholes or rust damage. Have the car put on a lift and inspected by a shop that knows how to inspect the exhaust system. General advice is that you always need to correct these type of problems quickly due to health hazards of breathing exhaust gases which can have toxic effects accumulating in the bloodstream. |
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