car repair diagnosis

March 31, 2005 10:02 AM

How can I figure out what's leaking from my car? (And other maladies...) Does anyone know of a site -- like WebMD, but for cars -- where I can type in symptoms and narrow down what might be wrong with a car? I know that I can go to a mechanic, but sometimes the first question is whether it's even safe to drive the car to the mechanic.

I am primarily looking for sites so I can do my own research in the future, but while I'm at it, if anyone has any ideas about my particular symptoms today, that's cool too. The oil change place has noted for a while that the engine rear main seal leaks. But in the last week, there's been a gasoline smell around the car while it's being driven. Last night the car was driven a short distance and, when it was idling, was dripping a liquid from in front of the rear passenger-side wheel. The dripping stopped once the car was no longer running. Is this the rear main seal? I put a pan underneath the car overnight but it hasn't collected anything. Is it safe to drive a car that leaks as it goes? The mechanic I prefer to use is located an hour's drive away.

posted by xo to travel & transportation (10 comments total)

A lot of the good auto sites are vendor specific. What kind of car/model/powertrain do you have? What colour and consistency is the fluid that leaked out? is it slippery or drying? What does the leaking fluid smell like? Don't be afraid to get it on your fingers, with the exception of battery fluid nothing that could leak from your car will hurt you if it isn't steaming hot.

Just a wag it sounds like you have a small or pin hole gas leak because of the smell and the fact that it stopped when the car stopped. The electric fuel pump was turned off with the car and the leak isn't large enough to leak when there is no pressure. The leak is probably in one of the rubber lines joining the steel gas line on the body to the fuel filter. From the location this is unlikely to be a main seal unless you have a Fiero or Bug or some other rear/mid engined vehicle.
posted by Mitheral at 10:19 AM on March 31, 2005

Colors of liquids may also help...
posted by blackkar at 10:21 AM on March 31, 2005

Mitheral is probably correct.
posted by trharlan at 10:35 AM on March 31, 2005

Thanks so far everyone...

Today I started it up again, the leak resumed, and it is, in fact, gasoline. I assume that makes it unsafe to drive?

The car is a Plymouth Acclaim from the early '90s. Any good site recommendations?
posted by xo at 10:51 AM on March 31, 2005

If it's leaking gasoline, not only shouldn't you drive it, but you should get someone to come over and take care of it ASAP. Gasoline is very dangerous stuff to have around, even if you don't get a flame anywhere near it. If it rains, the gasoline could run off into a nearby stream or get into the ground water.

As for useful sites, you might try CarTalk's do-it-yourself guide.
posted by cerebus19 at 11:07 AM on March 31, 2005

It's a bit risky, I wouldn't go anywhere with it the way it is however I wouldn't freak out about it after all there is practically no leak if the car isn't running. Changing the rubber hoses isn't hard, I've done it in a gas station parking during a midnight blizzard on an older EEK. I'd do the fuel filter at the same time if that is where the leak is located. You will probably only need a flat screw driver to loosen the clamps and a pair of pliers to break the old lines free. If it isn't too cold a short sleeve shirt or no shirt at all is a good idea as it's practically impossible to change the lines/filter with out spilling a little gas. Not only will you have a hard time getting the smell out of clothing, your clothing acts like a wick. I'd have a hose running and near by or a fire extinguisher handy. Some clay kitty litter spread around on the ground before hand will help absorb the spills. Starting the car and then pulling the fuel pump relay until the car dies will remove the pressure from the lines.

You've got a late model EEK. A good start for your car would be AllPar and you should subscribe to the EEK mailing list if you really want to get into it. If you're interested in going fast(er) there are a couple good engine specific forums for the 2.5 (turbo and non) and the 3.0.

Though much maligned a Haynes (preferred) or Chilton's type book for your car will layout simple tasks like this and inform you of dangers. The next step up and about 4-5X as much is a factory service manual for your specific model. You can get them thru Chrysler, call your local dealer for the number. Both are handy for your skill level as the latter assumes you have a general idea of how cars are put together and function and the former is often incomplete or outright wrong on more complicated tasks.

PS: it's unusual on these cars for only the rear main seal to leak and you have to separate the transaxle from the engine to fix it. If you've got a 3L the front crank seal and cam seals front and rear are notorious leakers. They are easy to replace but you have to tear down the entire front of the engine to get to them which will take the novice a couple of days to complete.
posted by Mitheral at 11:38 AM on March 31, 2005

I second the CarTalk site; they even have Bulletin Boards where you can ask specific information about your problem with your car, and *real people* will post responses. I've had good luck with it.
posted by Doohickie at 1:21 PM on March 31, 2005

The leak from the rear main seal will show as dirty oil under the front half of the car, roughly where the transaxle and the engine meet. Often, the leaking oil is trailing from the leak point towards the back of the car's underbody.
posted by kc0dxh at 1:52 PM on March 31, 2005

The amount of gas it sounds like you're leaking is very small. It probably vaporizes quickly after being dropped on the ground. I personally wouldn't think twice about driving it. I've driven a car in the same condition for a week or two before finding the leak and fixing it. Worst thing that happened was it melted a small spot of my driveway. :)
posted by knave at 4:09 PM on March 31, 2005

Thanks all... as it turned out, another car needed to get towed to our driveway and while the tow-guy was here, he looked at my car and confirmed a hose leak of gasoline, as Mitheral suggested. He said it would be safe to drive to the service center, so I did and it was fixed for less than $100.

Also, I never realized why guys often have their shirts off while working under cars... wicking finally explains that! And also why there are so few female mechanics.
posted by xo at 3:57 PM on November 30, 2005