What is the potential damage of a temporarily partially submerged front end?

Question

I have a 2005 Nissan Sentra (base model, FWD, 1.8L 4-cyl engine) and I took some bad advice from the Maps app on my iPhone and I ended up driving on a very, very bad road. At one point, I drove into a puddle that was quite deep where the car got stuck with the front end partially submerged - I imagine the water level was probably more or less at wheel well height towards the front right.

I managed to get out by putting the car in reverse, then drive, etc until I was free. During the final reverse attempt I was giving the car a bit of gas and, though the front wheels were mostly slipping, I slowly crawled back up to safety. It was during this final attempt that the engine light came on in the car. The engine itself works though, and I drove about 100 miles or so after this without incident.

However, there's a new sound in the engine that's faint, but audible, especially at higher RPM. When I opened up my hood I noticed that the entire engine area was dirty, presumably from the mud water that was splashed up during my attempt to escape. I don't have a lot of money, so I guess what I'm wondering is:

• What may have caused the check engine light to come on? In the 1.5 years I've owned the car it's never come on before.

• For each possibility, what is the danger in continuing to drive the vehicle without taking it to be serviced?

• Is it safe to hose down the engine area to get rid of the dirt?

Answer 1

You engine compartment is not closed off from the elements even in normal driving. Water/mud/dust gets in there and cars still run for years and years. I'd say you didn't do that much damage if any.

Is the engine light still on? Most of the things which are hooked up to car's computer are various sensors and if one of them gives off wacky reading, the computer throws a code and a light comes on. Lots of times, the sensor goes back to normal and after few days the light goes off by itself.

If you have a code reader and are curious, you can always hook that up to your car and see which sensor actually gave bad reading. If you don't have the reader, you can go to any autozone (I think advance auto also does that) and they'll read it for free. Write down the code and then search online what that code means for your specific car (sometimes generic code meanings don't always match with actual cars).

If the light stays on, most of the time you can still drive the car without any problems but your mileage might drop. You should still get it fixed, but you don't have to drop everything and do it this instant.

I would not recommend hosing down the engine. If you are concerned about dirt, I'd say just take some paper towels, some brushes and a purple power solution and spend some quality time with your car. Or just wait for that dirt to fall off as you keep driving if you are not that concerned.

As far as "faint new sound", could it be that it was always there and probably normal, but you are hearing it now because you are looking for something to be wrong because you are freaking out that you may have damaged the car?

Answer 2

I live in Louisiana, where it rains a lot and giant puddles are known to exist. I noticed when cars came in after being sub-marined, depending on the severity, the following:

• Damaged Mass Airflow Sensor (Check engine light comes on)
• Damaged Air speed sensor (If equipped)
• Flooded air box (Throws off mixture, and soaks filter)
• Damaged engine rods (Very severe, since water is almost incompressible. If you engine was damaged, and you have a bent rod, it might be vibrating extra.)

Make sure before you drive again, check your oil for water contamination, dry your air filter, clean your airflow sensor, and ensure there is no water in you air box.