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I recently bought a 2000 Subaru Outback Limited with 117k miles on it. Bought it from the original owner with all records. Headgasket was done 22k miles ago (3 years ago) but I am worried that it is going out again... I took it in because there was exhaust coming in through the cabin (would smell when first started up car and when stopped; also smelled like something was burning when I got out of the car). Took it to the shop and was told that it has an oil leak and that the exhaust gasket was leaking. Got new valve cover gasket, spark plug seal, valve cover seal washer, exhaust gasket and oil to fill to capacity per manufacturer eo. Now the check engine light is on, about 50 miles later (scan says needs new sensor; it has a brand new catalytic convertor)... Also, when I took it into Firestone for an a/c refresh a few days prior, they recommended new radiator hoses, coolant system services/flush with sealer and spark plug with fuel system cleaning.. After doing some research online, I feel like the headgasket might need to be done again; what do you think?
Amy, that's a well known problem with those Subarus. We did the same for 2 Outbacks (under Subaru warranty) but that was it. There was no need for second time repair with our cars. That check engine is a real trouble for many cars but its possible a sensor (which one?) needs replacement. On the other hand, the CE light may be on, following the catalytic converter job. Its not an emergency, unless you need to pass inspection. Just drive it.
Personally I really hate the arrangement of the CE warning light and the converter.
the typical failure mode of the head gasket(s) on this series is an external coolant seep at the head gasket dripping onto the exhaust system, with the nuisance of the anti-freeze smell entering the car and the constant need to top up the radiator/cooling system. Without this symptom, it's unlikely that your car has a new head gasket failure; the replacement metal sandwich head gaskets from Subie or the aftermarket in the last few years have been very durable.
The Valve Cover gasket set and spark plug tube seals are common age/heat failure items, although these should have been replaced at the time of the head gasket replacement. In my shop, I'd replace all of the related tuning items ... spark plugs, etc. ... because these also last a very long time (the better part of 100K miles) in normal service with the proper items and the labor won't need to be duplicated.
The check engine light will have set a DTC code. You need to get that scanned so you can find out what the computer is logging as a problem area; you can buy your own scanner for a few dollars or most of the box store auto parts merchandisers will scan it for free. If it has set the code for the catalytic converter operating below threshold efficiency, it's more likely an oxy sensor problem than the catalytic converter, especially if there's a fairly new converter installed. This could be an oxy sensor failure or a wiring/connector failure, especially if somebody has replaced an oxy sensor with a universal fit unit instead of the dedicated OE connector sensor. In my shop, if it appears to be an oxy sensor problem, I will replace both the front and back sensors for my customers; this usually takes care of the problem. Of course, if there's other DTC codes, you'll need to address those issues.
Amy, that's a well known problem with those Subarus. We did the same for 2 Outbacks (under Subaru warranty) but that was it. There was no need for second time repair with our cars. That check engine is a real trouble for many cars but its possible a sensor (which one?) needs replacement. On the other hand, the CE light may be on, following the catalytic converter job. Its not an emergency, unless you need to pass inspection. Just drive it.
Personally I really hate the arrangement of the CE warning light and the converter.
I know of some people who have gotten the head gasket repair, and the same problem has reappeared 35,000 miles later. One of the Subaru's affected has a perfect-looking body (no rust, scratches, dents, and the rest), but he is not sure if Subaru will take care of the problem once more. It's a 2005 model.
Apparently the scan indicated that it is due to oxygen sensor..
Looks like the oxygen sensors were done at 97k miles at the same time as the headgasket (3 years ago, 22k miles ago). Catalytic Convertor was done 1000 miles ago.
It would be great if it really only needs oxygen sensor(s).
Apparently the scan indicated that it is due to oxygen sensor..
Looks like the oxygen sensors were done at 97k miles at the same time as the headgasket (3 years ago, 22k miles ago). Catalytic Convertor was done 1000 miles ago.
It would be great if it really only needs oxygen sensor(s).
I'd be looking at the oxy sensors that were installed ...
I've seen a lot of premature failures from the universal fit oxy sensors and have been bitten enough times on comebacks over the years to try to save a customer a few dollars with these that I will now not install them.
Check to see if the correct OE fitted connector oxy sensors were installed. I recently bought a set for my 2000 OBW from O'Reilly's, and they were inexpensive at around $80 each retail (the front sensor was a few dollars less than the rear, due, I guess, to the shorter pigtail on the front sensor).
In any event, if a scan or 'scope shows a faulty O2 sensor and you cannot find a fault with the wiring, then it's relatively simple/inexpensive to replace. These are typically good for 75,000 +/- miles, but premature failures can happen for a wide range of reasons; don't forget to keep clean air filters in this car and periodically use a quality FI cleaner now and then (I like Techron, Lucas, or Power Service, but there are others that can give decent results, too).
Your Subie has a very good diagnostic computer program for engine performance issues. For example, if there's a cylinder misfiring that could be causing an oxy sensor (or catalytic converter) failure, it will set a misfire DTC/Check Engine Light for that cylinder. IMO, it's also prudent practice to replace the ignition wire set on these cars every 100K miles with a quality fitted set ... they do seem to get "tired" after awhile in the heat and the spark delivery can get flaky (especially if one of the spark plug tube seals at the VC was seeping engine oil onto the spark plug boot). I've seen more than a few of these wire sets fail at the ignition coil output terminals, too ... you can readily check to see if there's corrosion at these ends instead of bright brass on the wire end; if so, clean up the coil and replace the wire set.
The check engine light will have set a DTC code. You need to get that scanned so you can find out what the computer is logging as a problem area
Sunsprit, as auto professional, maybe you can explain the dubious arrangement with CE warning light and the code reading (and interpreting). Today most cars are equipped with displays. Why can't the car computer analyze the problem source and display it graphically and/or in plain English? For example, on my previous Camry, the low tire pressure warning. Only after checking it (at my tire dealer) I discovered that it was due to change in temperatures, following a very cold night. But here is the real problem: even after pumping in more air, the light stayed on for 3-4 additional miles, a time period I was totally puzzled about the problem. Should I let my young daughter drive it with the light on? Is it safe? The car could simply display: "Right front tire pressure dropped from 35psi to 30 psi, but now is back on to 35psi...(its basic 1980s technology).
Sunsprit, as auto professional, maybe you can explain the dubious arrangement with CE warning light and the code reading (and interpreting). Today most cars are equipped with displays. Why can't the car computer analyze the problem source and display it graphically and/or in plain English? For example, on my previous Camry, the low tire pressure warning. Only after checking it (at my tire dealer) I discovered that it was due to change in temperatures, following a very cold night. But here is the real problem: even after pumping in more air, the light stayed on for 3-4 additional miles, a time period I was totally puzzled about the problem. Should I let my young daughter drive it with the light on? Is it safe? The car could simply display: "Right front tire pressure dropped from 35psi to 30 psi, but now is back on to 35psi...(its basic 1980s technology).
While I think this line of questioning deserves it's own thread ...
Here's the problem, as I see it ... and you've commingled two entirely different systems, the engine DTC and the TPS systems:
The warning systems are there by federal emissions standards (for the check engine light system), and the parameters for what they must display were set up not by the manufacturers, but the feds seeking to get better control of cars on the road not complying with emissions standards. The on-board software is targeted to ascertaining that some critical functions of the engine aren't functioning according to spec, but the limit of the system is to announce the malfunction, not determine the causation. So, for example, a "misfire" code for a certain cylinder can only alert that malfunction, but it cannot ascertain that there may be a mechanical failure, ignition component failure, or a fuel delivery problem.
All the computer can do at best is determine the improper running of the engine ... and they're none too sensitive, at that. I've seen some pretty poor fuel economy numbers and driveability problems that didn't trigger a code yet found a green crusty ignition wire end that had fallen off inside an ignition coil ... or a spark plug (like one here that sits on my desk so I can show customers) that had a cracked insulator and a black carbon trace down the side of the 'plug. Or driveability problems from an EGR system where the solenoid was electrically functioning properly according to the signal diagnostic at the ECU, but the actual movement of the rod was stuck. Similarly, the ECU software may not determine that various sensors are not functioning properly, such as an intermittent crankshaft or camshaft sensor; when they fail to a point when a tech can capture the problem, then they are replaced. Sometimes, you have to have a no-start condition before the failure can be diagnosed. Still other intermittent situations can be nightmares to trace ... debris or foreign matter in a fuel tank causing intermittent fuel pressure delivery can be difficult to isolate and discover until there's a pump or fuel pressure/delivery problem.
IMO, the automotive buying public has been woefully mislead as to the nature of the the computerized trouble light warnings on the dash. They are not diagnostics, they are merely indicators of an emissions fault detected by the computer which can be as simple as a component failure or as intermittent as a failed wiring connection giving false information to the computer. Many of these codes do not interfere with the safe operation of the vehicle. Plain english reporting would not be able to address the many potential causations of the warning CEL.
The TPS software warning systems have their parameters set by various manufacturers. The system in your Camry apparently is a bit too sensitive for the operating conditions where it was being driven. A prudent driver would note the warning and check the tire pressure as you have done. Upon finding that the tire pressure was OK, I'd keep on driving ... warning light on or not ... the car is safe to drive at that point for you or your daughter. Again, a plain english tire pressure history report would be a level of diagnostic information which the industry has not seen fit to pursue ... nor, I think, a feature that you'd want to pay for on your vehicle.
Tire inflation is inferred by the computer by counting the number of each revolutions per unit time. When one tire is rotating more then the others or a pre programmed number it infers that that tire, or in the case of the preset number, all of them, have a lower pressure than specified. It may take a few miles for the computer to collect enough data. I always inflate the tires about 5 lbs. above the recommended pressure because it improves the handling even it makes the ride a bit harsher.
Greg W describes an "indirect" monitoring system, which some manufacturers use.
Others use a "direct" monitoring system, which actually transmits a tire pressure signal to the system.
Either way, if you get a warning signal and verify that the tire is properly inflated, then the vehicle is safe to drive.
More info about seasonal cold weather operations available on the gov website, you can google tire pressure monitoring systems. They do mention that checking the tires is recommended in cold weather if a warning is displayed, but that if you check the tires, they're OK to drive; they explain the normal tire pressure drop with lower temperatures.
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