So I was driving home yesterday and some super crazy rainstorm came out of nowhere and it was almost like a hurricane it was raining so much. I was going uphill on the highway so didn't think I would have to worry about hydrolocking, but went through a patch of water that was probably 2-3 inches deep and was shooting 3-5 foot tall waves from the side of the car and I was only going about 20 mph.

I should note that the wheel well liner on the intake side got torn off so the cold air intake filter is directly exposed to the wave of water generated by my tire going through the puddle.

The engine then died and I coasted to the side of the road. Since it wasn't enough water to fully submerge the intake I figured it probably just smothered it and the engine died because it wasn't getting enough air. I tried to restart it and no go. Waited about 10 minutes and tried again and it sort of started but sputtered out. So I had someone pick me up and came back to it about 3 hours later and it sputtered out the first couple times I tried it, but then it started and ran on it's own.

Problem was that when it ran it sounded like a damn diesel. Really loud knocking noise when it ran so I turned it off after 2-3 seconds. Came back to it again today and it was still knocking while running but it quieted down a bit. I had it towed to my place so I wouldn't drive it like that.

So what should I look for if something got damaged? I'm hoping the valve adjustment just got thrown off, but if something else got damaged how can I tell? If the valves got bent what part of them would be bent (the round flat part inside the cylinder or the long thin part inside the valve springs)?


TL;DR:
-drove through puddle that sprayed a LOT of water up on my cold air intake filter
-engine died
-engine running now but with loud knocking noise
-what could cause this loud knocking noise?

 

Remove the spark plugs and turn the engine over by hand. This will help verify water in the cylinders. If there is water left in the cylinders from the rain storm then get as much out as you can and let it sit awhile without the spark plugs in. Then do a compression test on each cylinder. If you have low compression at all then put a tablespoon of motor oil in the cylinder and do a compression test on that cylinder again. If the compression goes up then you know it has something to do with the bottom end of the block. If the compression is still low then it has something to do with the head(ex. valves). The knocking sound could be a rod knock.

This the reason why I am NOT a fan of cold air intakes. The risk is not worth the gain.

 

Thanks IllGottenGains I'll do that. I doubt it would have been a problem if I had replaced the fender liner so the filter wasn't directly exposed like that.

 

I worked in shop. I have seen enough cars with cold air intakes come in after heavy rains with hydro locked engines. It was enough for me to never get a cold air intake for any of my cars.

 

ok, so pulled all the plugs. They all looked normal. No water left in the cylinders.

Ran a compression test on each cylinder. 5 of them were well within spec (~1200 kPa with an expected 1250 in a new engine), the 6th... was screwed with a terrible 600 kPa. Puta couple capfulls of oil in there and ran again and got 750-800 kPa.

Am I looking at an engine rebuild?

 

Did you check what the accepted tolerance for cylinder compression is according to manufacturer specifications? I don't have the service manual so maybe someone else that reads this thread might have one can chime in. Does the car make any knocking sound at all from the engine area?

 

In all likelihood the bottom end is damaged.

 

yes the accepted tolerance is 900 kPa with 1250 kPa (new) with a max variance of 200 kPa. Unfortunately that one cylinder makes the variance 500-600. Yeah the knocking sound it makes while running is from inside the engine. It also makes the knocking sound even when I crank it.

If the bottom end is damage am I looking at having to rebuild the engine? If so I might as well just get another engine to drop in.

 

Drop a another motor in there. No point in spending money to rebuild a block that you have no clue what is still reusable internally.

 

I guess I'll do the J32 upgrade then. Just have to find a damn job first. Stupid economy.

 

Thanks for all your help Ill.

 

man that intake kiilleed herr

 

yeah fortunately insurance covered a replacement engine, and I shoudl have the car back within a day.

I think I'm going to cut the CAI down to be a short ram. Any suggestions for what to cut it with?