So, with the recent NE storm I suddenly found myself in this "lake" in a dark parking lot, and the lake was apparently rather deep because before I knew it I was already making a pretty good wake. When I got to the "shore" and turned to the county road, I found that though the engine was still running, it was running rough, and the car wouldn't accelerate.

I pulled over, noticed clouds of white steam coming from behind, and then ECU spit P0301 code. I waited a few minutes, the idle run seemed to have smoothed down, and tried driving away again. Didn't go too far because with throttle depressed the engine started choking again, and more P030* codes showed up. So, I stopped again, this time shut the engine down, opened the hood just for the fun of it (didn't have any instruments anyway). There was clearly a sign of a big splash that got on top of the engine from the driver's side, some water was on the spark plug coils, on EGR and some other electrical connectors. I wiped down visible puddles as well as I could with the rain still pouring, and went back inside to google the error codes. ECU was already showing misfires in all cylinders but two. 10 minutes later I came to the conclusion that if it was misfiring, it was because of water inside the engine, and hardly on the connectors because they all seemed to be very well insulated. And since the engine was still able to run, it was probably best just to let it run at idle until it dried down. So, I did it, and 10 more mins later I was able to drive away with ECU throwing one additional P0300 down the road. I drove about 20 miles to home and in the end the car seemed to run as usual, perhaps a tad underpowered.

At home I found a fully soaked air filter, puddle of water in the depression in the throttle body right before the throttle valve, and three dried and rehydrated mice underneath the filter.

So I was about to forget about this whole thing but then foolishly went to acurazine and read all these horror stories about hydrolocking TL engines, bent valves, diagnostic fees and many $K repair bills. Hence the question... Considering my experience above, should I do smth with the engine aside from replacing the filter and installing a mouse trap, or should I just take a note and take jet ski from work next time it rains so bad?

 

Did you look for a hole or a crack where the mice might have gotten under the filter?

 

The P0300 means you had multiple misfires. I say take all your plugs out, either dry (or replace), dry or replace air filter, look for any water in the cylinders, and like Beezle said, check for holes/cracks where the mice were at. It doesn't sound like you did any major damage, but came close, from reading your post.

 

I fugured, they just climbed up the plastic intake pipe. I just don't know why they chose to die there instead of escaping back.

 

change your oil

 

I would say you lucked out. Follow the advice of changing filter, and checking plugs and you should be good.

An oil change certainly woudn't hurt, but I'm not sure it's actually necessary based on what happened. How much water would actually get into the crankcase if you didn't hydrolock? You have Jeeps with snorkels that do that all time and don't change their oil each stream encounter.

 

Get a tuneup

 

Well, here is one of the plugs... It's dry albeit rusty. Is there something in particular that I should be looking for?

 

Oops. One of the plugs was not tight. In fact, it was loose, and I unscrewed it with bare hands... The coil stem is covered with soot and reeks of gas. Don't know whether it's related or just smth else that was going on with the engine.

 

tune up time

 

What do you all mean by tune up? Smth that dealer would do (never heard of it), or smth that you do in your garages? The car has only 75K btw.

 

You got lucky. Water by itself causes misfires. It puts out the fire. You can have misfires from water ingestion and not hurt anything.

If the engine is running there's no reason to pull the plugs. You have a power stroke more than 5 times a second at idle. The cylinders are completely free of water after a second or less. There's always the chance that the incompressible water did damage by bending a rod but the misfires you experienced were from the water putting out the fire. If you begin having misfires down the road you probably lost compression from a bent rod. This lowers the actual compression ratio. A leak down test won't catch it but a compression test will. The weakened rod will eventually break and you've got a blown engine.

You did catch a common and sometimes expensive problem with these engines, loose spark plugs. I would look at this whole experience as a positive thing because you just saved yourself a lot of money catching that loose plug before it ejects ruining the threads in the head and the coil.

I would check the oil. If there is water, change it. If there's just a trace of water such as water vapor on the underside of the fill cap, a 30+ minute freeway drive will take care of it.

I would have been careful going deep into the throttle after this first happened. You can end up with water puddling in the intake tract and being sucked into the cylinders as you give it more throttle. Driving easy or just idling for a while afterward would have been good to help evaporate the water or at least suck it in at a lower rate.

You can do a compression test now or drive it as if nothing happened and keep an eye out for more misfire codes. Chances are if you get misfires down the road its time to keep the rpms down and start saving for a new shortblock.

 

Thanks, everybody. I appreciate the detailed advice and explanations. The car runs OK, there is no condensation and no CEL yet. The whole thing was a little scary, but I've learnt a lot too. So, yay.