Puddle water in the engine - disaster?
Discussion
The short version: I hit a puddle last night and developed a misfire which shortly went away completely, but returned today accompanied by a horrendous clattering from the engine. What do I do now? It's a mk1, 1.8, n/a.
The long version:
On the way to the missus's house last night I hit a huge puddle at around 50MPH, causing water to be splashed everywhere. Immediately afterwards, the engine started misfiring and there was a distinct lack of power, as well as a 'slapping' noise coming from the under the bonnet. Unfortunately I couldn't immediately pull over as it was pitch black and on a blind corner of a NSL road.
By the time I'd pulled off into a side road (approx 20 seconds later) the engine was sounding much better and only misfiring occasionally so I decided to keep going and nurse it the 1/2 mile to the house. By the time I arrived it sounded back to normal with no misfiring and a nice smooth idle, so I turned it off and went inside.
Come this morning, I fire it up to drive the 70 miles back to my place and it sounds sweet as usual, with no indication of a problem. After a couple of miles, however, the misfire returns along with a serious drop in power, but then goes away and is replaced by a horrible clattering noise from the engine. It sounds mechanical and increases with revs.
Have I totally annihilated the engine? I got it brought back home on a flatbed this afternoon, and it's now sitting sadly in my garage waiting for me to show it some love. The annoying thing is I'd just fitted a new cam cover gasket, plugs and leads, and I'm supposed to be road tripping around France next week
The long version:
On the way to the missus's house last night I hit a huge puddle at around 50MPH, causing water to be splashed everywhere. Immediately afterwards, the engine started misfiring and there was a distinct lack of power, as well as a 'slapping' noise coming from the under the bonnet. Unfortunately I couldn't immediately pull over as it was pitch black and on a blind corner of a NSL road.
By the time I'd pulled off into a side road (approx 20 seconds later) the engine was sounding much better and only misfiring occasionally so I decided to keep going and nurse it the 1/2 mile to the house. By the time I arrived it sounded back to normal with no misfiring and a nice smooth idle, so I turned it off and went inside.
Come this morning, I fire it up to drive the 70 miles back to my place and it sounds sweet as usual, with no indication of a problem. After a couple of miles, however, the misfire returns along with a serious drop in power, but then goes away and is replaced by a horrible clattering noise from the engine. It sounds mechanical and increases with revs.
Have I totally annihilated the engine? I got it brought back home on a flatbed this afternoon, and it's now sitting sadly in my garage waiting for me to show it some love. The annoying thing is I'd just fitted a new cam cover gasket, plugs and leads, and I'm supposed to be road tripping around France next week
Worst case the engine has ingested water and something is bent - but it surely wouldn't intermittently run OK if this was the case, and I'd imagine it would take rather a lot of water?
Introduce the leads, plug tops and coil pack to the business end of a can of WD40. Let it all dry out (the stuff is flammable afaik
) and see if that helps. I had a coolant hose let go and condensed steam seeping down past the poorly fitting aftermarket leads was enough to cause poor contact and a misfire. The WD40 got me mobile again until I could fit new leads for peace of mind. 
Edit: Sorry, I misread that and didn't realise the misfire was gone! Most of what I just said is probably complete bolleaux.
Introduce the leads, plug tops and coil pack to the business end of a can of WD40. Let it all dry out (the stuff is flammable afaik
) and see if that helps. I had a coolant hose let go and condensed steam seeping down past the poorly fitting aftermarket leads was enough to cause poor contact and a misfire. The WD40 got me mobile again until I could fit new leads for peace of mind. Edit: Sorry, I misread that and didn't realise the misfire was gone! Most of what I just said is probably complete bolleaux.
Edited by BonzoG on Saturday 25th June 22:27
I think the big worry is that if the water got sucked into the engine and into one or more cylinders. Water doesn't compress and this can bend important bits like con rods. I'd have guessed that it would run badly, if at all, and stay that way. Intermittent good running might point to something less terminal.
Its odd - as if the engine HAD suffered from ingested water, and bent a rod - thats not really an intermittent problem is it!?
Personally I'd start by checking nothing wierds happened to something otuside the engine, like a belt come off or god knows what.
Then remove the plugs, and turn the engine over by hand, make sure it feels ok. Then try turning it on the starter, again make sure it spins freely.
You could check the air intake pipes to see if theres any water in them, and the airbox too if you have one.
Then I'd check the coilpack, fuse box etc for signs of water. If it all seems dry, stick the plugs back in and see if it runs again.
Personally I'd start by checking nothing wierds happened to something otuside the engine, like a belt come off or god knows what.
Then remove the plugs, and turn the engine over by hand, make sure it feels ok. Then try turning it on the starter, again make sure it spins freely.
You could check the air intake pipes to see if theres any water in them, and the airbox too if you have one.
Then I'd check the coilpack, fuse box etc for signs of water. If it all seems dry, stick the plugs back in and see if it runs again.
So, a quick update: Yesterday I removed and checked the leads, spark plugs and coil pack, none of which displayed any obvious damage or signs of water. Likewise with the air filter (induction kit type, so perhaps more eager to suck in any water from the bay?), AFM and intake ducting. All looked dry, although there was what appeared to be evidence of a small amount of water that had dried out on the bottom of the AFM body.
I also took off the cam cover to check the cam lobes and HLAs, again they all appeared okay (to my untrained eye). I checked the timing belt in case it'd skipped any teeth but it all lined up properly.
I put everything back together and tried starting it - it cranked over okay and fired up but it ran really roughly and then shortly spluttered to a halt. It now refuses to start, but does crank over OK.
In (potentially) unrelated news, before this whole episode began I noticed that the #2 spark plug wasn't tightened properly and had been leaking exhaust gases. The spark plug looked like this:
Further inspection revealed that it appears to have been cross-threaded by whoever fitted the plugs before I bought the car. I replaced all 4 plugs but #2 was very hard to tighten up beyond hand-tight, so I think a new head is going to be required in any case.
I also took off the cam cover to check the cam lobes and HLAs, again they all appeared okay (to my untrained eye). I checked the timing belt in case it'd skipped any teeth but it all lined up properly.
I put everything back together and tried starting it - it cranked over okay and fired up but it ran really roughly and then shortly spluttered to a halt. It now refuses to start, but does crank over OK.
In (potentially) unrelated news, before this whole episode began I noticed that the #2 spark plug wasn't tightened properly and had been leaking exhaust gases. The spark plug looked like this:
Further inspection revealed that it appears to have been cross-threaded by whoever fitted the plugs before I bought the car. I replaced all 4 plugs but #2 was very hard to tighten up beyond hand-tight, so I think a new head is going to be required in any case.
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