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My car is making a loud rattling, knocking noise after you crank and drive

I was driving a my car about 90 miles I noticed that the oil light started to flicker on and off but i was going to try and make it home where I had oil, I stopped to get gas and when I cranked it it started making a horrible rattling, knocking noise coming from the engine area. I stopped and got some oil treatment, engine repair stuff and put it in. The car makes the noise the same all the time whether I am accelerating, driving at a constant speed, or just idling. I have not noticed any loss in power or any problems with how the car drives. I drove it home, about another 30 miles, and left it sitting over night. The next day when I cranked it it wasn’t making any noise so i drove the kids to school. After about 5 min or so it started up again. I cranked it again later and it did the same just idling, it was fine for a few min then started with the noise again. The noise is hard to pin point exactly where it is coming from, it is just some where around the engine area. It is a 1997 Ford Taurus station wagon. Does any body have any clue what might be wrong with it, and how much it will cost to fix, or is it just about dead.

When that oil pressure light started to flicker, you should have shut down the engine and pulled over at the very first safe place to stop. Failure to do that has most likely led to severe damage to bearings and other friction surfaces in this 14-15 year old engine. “Horrible rattling, knocking noises” are a pretty good confirmation that you have severely damaged the engine, and every time that you start that engine, you are driving coffin nails further into the casket for this car.

Unfortunately, “oil treatment” is not a lubricant. It is a Viscosity Index Improver, which means that it thickens oil. If you had very little oil in your crankcase (the most likely scenario), thickening the oil did not help the situation. If the flickering oil light was the result of a failing oil pump, thickening the oil might have been a temporary aid, but continuing to drive a car with a failing oil pump is one of the best ways to kill an engine.

No matter which of the above scenarios is the case, your present plan of continuing to drive the car is only going to ensure that the engine is beyond repair.

You never told us what you found when you checked the dipstick just before you added that STP-type stuff to the crankcase. What did the dipstick show? Did you actually add oil, or did you just add that STP-type stuff?

Most likely, this engine is already “toast”. However, if you want to have any hope of continuing to drive this car at minimal repair costs, you will have it towed to a reputable mechanic, and not continue to drive it.

Yeah, the dipstick…Tell us about that…How much oil did you have to add to get it back to the full mark…

I actually added 1/2 a quart of oil and one of the engine treatment stuff that came in a two part solution. I didn’t check the oil before adding all of that but after it was at normal level. And one of the other reason’s I didn’t stop was that i was pretty much in the middle of nowhere when the oil light came on too. I pretty much realize now what I should have done, so that part really wasn’t very helpful. I would still like to know if this is something that is worth fixing on such an old vehicle and about how much it will cost to fix?

Sounds like a rod knock, if it was something you were capable of fixing it you would have known what the noise was. Having someone else fix it will cost more than it is worth. Unless you have always wanted to take an engine apart and rebuild it you are just about done with this car.

That’s pretty much what I figured, I just didn’t want to waste my time or money towing this car to a mechanic to get fixed if that was the case. I was just really hoping that it might be something else.

I would not send it off to the shredder without a professional mechanic at least looking at it…Nobody here knows exactly what is wrong with your car… How many miles on it?? When did you last CHANGE the oil??

@Caddyman: /agree

From the keyboard, we’re all just making educated guesses by the comments you provide. Obviously, we haven’t seen the motor, so we can’t make a final fitness determination.

I did have a friend with a minor rod knock in a car…he drove it for 5 years and sold it. So just because it’s knocking, doesn’t mean you can’t continue with it. Having said that, with his you had to listen for it…it wasn’t so loud you could hear it in the cabin. The fact that the sound doesn’t change whether under load or not is hopeful, though. It may run like this for a while.

But get it checked out.


I last changed the oil about 2000 miles ago, and it has just under 180,000 miles on it. I have had it for about 2 1/2 years and never had any other problems with it, and have definitely got my money’s worth out of it. The biggest problem I have is I have VERY limited money and can’t really afford to have it looked at if it is shot. I don’t really want to junk it if it is something that can be fixed for a decent price. If there are any other possibilities it could be, than I will get it checked out. Any ideas???

I’d bet money you know someone who can come over with either a mechanic’s stethoscope, or even a metal rod, and get close to the noise source. If it’s in the block or head, it won’t take him (or her!) long to find it. If it’s not there, then one of the accessory units (which would kind of nullify over half of this thread). Really, it only takes a few minutes to get close to the noise source, or to at least eliminate major components. Not a definite “It’s the #3 rod”, but at least a “Yeah, it’s on the crank somewhere” type of answer.

Then you can decide if you want to think about selling it, getting a used motor or driving to a junk yard and getting whatever you can for it. Phone calls are cheap, anyway. Call around. See what happens.