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Hello all!
This is my first time posting here, I'm looking forward to contributing.

Heres my problem. I drove my 06' Beetle TDI into some pretty deep flood waters. Stalled out. (Please understand that I know how stupid this was.) I had a friend tow me out backwards. I pulled the air cleaner apart immediately and found the filter soaked, and a little water had made it's way past the filter into the MAF housing and such. Not so much that I was afraid of the engine having ingested a dangerous amount (of course I don't know what dangerous would be, but it was just a little damp, not flooded.)
I cleaned and dried everything and replaced the filter with new. I did not change the oil but it seemed free of any water at least on the dipstick and inside the filler cap. The engine was at no time submerged, the water was only up to maybe the middle of the front bumper on the drivers side only( I drove into a ditch that was not visible because of the flood waters. The car only tilted into it deeply on the one side.)
Upon restarting the car, which it did pretty quickly after cranking, although very rough running at first, a lot of water was blown out of the exhaust. I assume that the tailpipe had been submerged but did not notice this at the time.
I'm trying to provide as much info as possible to help a diagnosis but to make a long story shorter, the car runs pretty well now except for rough cold starting and some smoking. After warming up I think it is back to normal, possibly seems a little louder, but I may just be listening to hard.
The roughness and smoke is very disconcerting though.
So what do the experts think? Would this little bit of filtered water in the intake damage the MAF sensor? Or could the water in the exhaust have damaged the O2 sensor? Or something worse?
The car has 28K miles.
I was a mechanic 15 years ago but have been out of it so long newer cars are a little out of my league.

Thanks in advance for any advice!
Jonathan
 

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2 possibilities: something is wrong and the engine should not be run any more or everything is OK. Here are a few things to consider.

A diesel has very little space for water, remember that compression is like 19-1 or something. It doesn't take much water to cause a lot of damage. On the bright side, water has to go all the way through the intake, to the turbo (which can damage the turbo), through the intercooler which can help stop minor water, up to the intake. The problem is that you said water was blown ou thte exhaust. I would have removed the glow plugs before cranking so that any water that may have been in there or wasn't yet would have been blown out.

Water out the exhaust could have entered through a leak in the exhaust pipe, hopefully this is the case but I don't think so since you ahve rough starting and smoking.

These cars had bad MAFs, try unplugging the MAF. A TDI will run OK without it and this is the main test to determine a bad MAF. If it smooths out then this could be the problem. I think it should run OK without the o2 sensor too.
 

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Discussion Starter #3
a little follow up

I pulled MAF sensor connector. No change to running that I could notice at idle. Engine was kind of warm. I will try again when stone cold, where I have the rough running.

Grizzly: I'm pretty sure the tail pipe was under water for a few minutes. I think the exhaust filled up from the back. I think if I had passed water through the cylinders it would be a lot worse than it is, at least I'm hoping...
Runs good when hot, smooth, and mileage/power seems to be the same.

I really think it would be hard for much water to get through that filter. It's a tight fit. I have rebuilt engines that ingested water, it's not a pretty sight, but then they didn't run to well at all .

Thanks again.
Jonathan
 

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Sorry to hear that. Make sure there's no more water in the intake, get a compression test, and check the oil again before doing anything else. Hopefully insurance will take care of it.

The bad news is that since the air filter is on the driver's side, my guess is that the engine got minor hydrolock.

I would have removed the glow plugs (look like spark plugs) before cranking. Also remove the hose at the intercooler. If there's water in there it should pool there. A little bit of oil is normal.

Rough cold starting like it doesn't want to start or it sounds like crap until it's warmed up and then is smooth?

The problem is that a TDI runs off compression. Low compression = hard starting and rough running. Don't use a gasser compression tester since they don't have the range. 400-500 psi is about average on a TDI, about 150-180 psi on a few gassers by comparison. Because of the very high compression, it doesn't take much water or oil to bend rods. Even a stuck injector that has pooled diesel in the cylinder can bend a rod. This is why I think the engine has a little hydrolock. The rough running when cold could be due to low compression on 1 cylinder. When it warms up it smooths out as compression comes up. I would get a compression test before getting worried since what's done is done. If you're lucky it could be a fueling problem.

Diesels have a lot of blowby, if water reached the intake then it might have gotten into the oil. The trans gear case has a vent and water might be in your transmission gear oil too. Please note that your 06 needs special oil for pumpe duse engines.

The O2 sensor has nothing to do with fuel metering, it's for the EGR. It should have no effect on the car's running. Look thorugh the FAQ section on the MAF testing article. You can unplug it and the car will go to a default map. It should run fine in that mode, albiet with lower efficiency. Another test is that a good plugged in MAF should let the engine go to about 5100 RPM. I doubt your MAF is otherwise bad after only 28k miles.

If the turbo hit standing water I think it could be damaged. The journal bearings are floating on oil so it can move a little bit but the turbo wheel doesn't have a whole lot of mass and damage to the bearings will put oil into the intake. A little oil can cause oil burning, a lot of oil will cause the engine to run off oil and runaway if it's bad. A runaway engine also equals engine death.

Water out the exhaust probably came in through the tailpipe. If compression is fine and the car runs the same, I would just drive a bit and see if it burns off.

Hope that water has gotten into the fuel or there's a sensor problem. On the bright side, these cars are easy to work on. Someone asked about engine removal, here is that thread and some pics.: http://www.myturbodiesel.com/forum/showthread.php?t=1167 . With the New Beetle, it's relatively easy to remove the fenders, the front service carrier (VW/Audi cars have the bumper support, radiator, etc., on a single piece that comes off easy after the front fasica is removed), and the engine comes out the front.
 

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Discussion Starter #5
Thanks

CCBB
Thanks for the reply. When I say it runs rough it's only maybe for a minute or three. Starts instantly, never stalls, just coughs a little for a minute. Smokes bad only on startup, then gets better. Needless to say it was perfect before with only 28K miles. I'm in South Carolina but it's been in the 30's and 40's in the mornings.

It's been a couple of weeks since this happened. We've been driving the car since. Probably two tanks of fuel. I've run some diesel treatment/injector cleaner just in case. Mileage and performance seem normal.

Would a bad MAFS cause any symptoms like this? I read that they are pretty sensitive. Also I forgot to mention that I dried the intake with a heat gun, but was extremely careful. I never let it get hotter than was comfortable for my hand to be in front of the gun. I really wanted to make sure it was dry, but was concerned about damaging the MAFS.

I know it sounds like I'm trying to avoid accepting the possibility of internal engine damage and I am! I guess a compression test is in order.

Do you think just a couple of minutes of warming up would be enough to bring the compression back up? It seems to take for ever for the little blue cold engine light to go off.

Also it shows no CEL. I'm not even sure what kind of warning lights the car has. It's very frustrating not even having a temp gauge.

Any other possibilities? What symptoms would a damaged turbo show?

Thanks again
Jonathan
 

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FYI, your car is an mk4. The NB and Golf stayed in the 4th gen longer than the Jetta. I'll move this post later.

The MAF is sensitive but I don't think it would cause rough running and smoke on startup, the MAF normally causes low power since it senses less air. To me, rough running means an imbalance in compression or fuel quantity between the cylinders. I would get a compression test. A cheaper tester should work since you're also looking for consistency across the cylinders. The cheap ones on ebay might read a little high or low but they should at least be consistent.

Yes, remember that a diesel sees higher cylinder pressures. Turbo engines and diesel engines have to let the pistons expand more and the high compression also equals blowby. Once it warms up, the engine seals better. I live in the Northeast and during winter, you can really hear the difference between summer and winter startups. A lot more clatter in the winter. That doesn't mean it's okay to continue to drive with possible damage that could be fixed now instead of causing problems soon.

Take it to your local parts store and have them scan it for codes.

Worn turbo or damaged bearing is normally smoke during normal driving. If it really did touch the housing then it either instantly breaks the shaft and jams in place or gets nicked and slowly wobbles and damages the bearing and then snaps or blows oil. Removing the intercooler hose and seeing how much oil is in there can tell you how much oil it's leaking. A little is normal.
 

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If performance is normal then i bet the turbo is fine. The smoke is coming from somewhere though. If it smells like oil then it's probably that, if it's diesel then find out why.
 

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Thanks

Well i guess I'm going to get a compression tester.

I'm still not 100% convinced it's in the engine. Do you think a damaged turbo could leak oil while resting and explain the burst of smoke on startup but then none there after?

Cold start up this morning. With MAF disconnected. No real difference.

It starts right up, blows a bit of smoke and hiccups a bit and then is clean and running decent in a very short period of time. I mean like 20 seconds. If the car was ten years old I probably wouldn't think twice about it, but it was perfect before the "incident"

Would water in the fuel or malfunctioning injectors cause any symptoms like these? I need to get some one else to start the car so I can actually smell the smoke, it happens to quick to catch it, but I would say it smells more like un/badly burned fuel than oil smoke. Of course I guess low compression would explain this also.

Thanks again for any insight. I will be following your suggestions, doing a compression test and going from there.

What do you think would have happened if there was hydro-lock? I know what can happen, but I'm curious if there is any anecdotal evidence on this engine? I have seen hydro-locked engines with cracked rings and bent connecting rods. I think if I had cracked rings it would be a lot worse. I guess a slightly bent rod would decrease compression and explain it all. Uhgghhh now this sounds to likely....

Jonathan

PS I will say again though that upon removing the MAF housing to dry it out the moisture inside was on the order of condensation on the walls of the plastic pipe, and almost none in the aluminum intake section. No where near standing water.
 

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New question?

What is the adapter size needed for a compression tester for my engine?

24 mm X 2? If so I can get this easy. I will be searching the site here but it would help if someone knows this quickly.

Thanks!

Jonathan

Edit: So it looks like it's 24 mm X 2 for injector and 10 mm X 1 for glow plug? Does this sound correct? Which is going to be easier? I'm guessing glow plug but the problem is the adapter is harder to find. The 24mm comes in a lot of sets.
 

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Get the 10mm one, glow plugs are MUCH easier to remove than injectors, especially onthis engine.

PS, on this engine the rods tend to bend. They are also sensitive to small changes in cam timing. Fuel timing is controlled by the ECU.

Also, it's normal for a small puff of smoke on startup. 20 seconds is nothing. The hiccup sounds strange though. Some people complained of a rough idle after warm up bu tthat's not your problem.
 

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Grizzly
Thanks for that, I guess I'll keep looking for the 10 mm

Yeah the puff of smoke would be ok if it hadn't started after the flood. There was nothing noticeable before. And then the roughness. It's weird though, like I said, just a little not even a minute now. I don't see that being low compression and changing in 20 secs. Maybe oil or fuel leaking down into the cylinder that gets burned off in that time?

I'm working on finding a tester locally that isn't Snap-On. As much as I'd like to have it they're a little pricey!

Jonathan
 

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Hm, I was thinking a minute or three until smooth running, not 20 seconds. I doubt compression changes that fast. Maybe the puff of oil was always there? Check compression and then go from there. You've been driving it so if there was going to be a catastrophic failure I'd think it would have already happened. Sometimes timing on the camshaft can be adjusted to smooth out a rough idle but that's during normal driving. It might help to get a vag-com cable, the VW diagnostic cable, if you have a laptop computer. Google ross tech vag com and check out their page. If timing is infact somehow changed, you can see it through that. Don't fool around with the timing belt unless you have the proper tools! If cam timing is retarded (don't know how it would have changed due to the incident), then you can see it through vag com. If this is the case, it should have a rough idle even when it's warm.

The turbo would smoke at all times if it was bad, the one thing that sounds bad is that the engine stalled out.
 

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CCBB

Sorry if I mislead you with the minute or three description, I guess I was thinking thats how long it took immediately after the swamping but it seemed to get progressively better as things dried out. I wouldn't say the idle was perfect after warming up, but good enough that your average observer (my wife thinks its fine) wouldn't notice anything. I think I detect a little "missing" for lack of a better word but there is no noticeable change in idle engine speed as shown by the tach.

My other car is a diesel MB G-Wagen whose intake system (filter box gasketing and filter etc.) is designed to not allow water to pass. It's not uncommon to stall one of them by sucking water and mud into the filter, but no harm done. I was thinking that this was what happened, once the filter got saturated it couldn't pass any air and then stalled, not that water had reached the turbo or cylinders. Obviously a little got through since I saw it in the intake but it seemed like a very small amount, vapor even, not enough to pool anywhere. Unless what was there had already gotten sucked in to the engine.


Jonathan

Again I really appreciate the patience and help. I will keep you informed.
 

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You'd think there's a water trap in there. I don't think much water can get past the air filter unless it's really submerged. The intercooler also sort of blocks the water. Unless it really sucked in a big gulp...
 

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Here's what I think is happening. I've seen it several times.

The combustion chamber is only 24cc's. If you put more water than that... about a 1/3 of a cup... you will bend a rod.

What happens at startup can be seen by VAG-COM in the Engine/Module 13. That is idle balance. initially, the balance will be rough. The the idle balance program in the ecu kicks in.

What the idle compensation will show is the relative balance of the cylinders by an arbitrary number...+2 to -2. The cylinder which is weak will require more fueling; the stronger cylinders will have less fueling or a negative number. That is done by reading the fueling of the #3 injector along with the relative time between cylinders as measured by the crank sensor on the block in front of #4 cylinder.

Harbor Freight has a cheap, yet effective compression tester... around $25. If the compression results and the Module 13 results correlate, you can bet your bottom dollar you have a bent rod.

Let me know what you figure out...

Frank
[email protected]
 

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Even though it's not water tight, woudn't the snow screen stop water from splashing down? And the air filter is pretty tight so that must stop water too.
 

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The snow screen just stops large debris. Take it out and you can easily see that water can pass through. I can see how it might slow water flow but that's it.

The air filter is tight. But if you sucked in that much water, it can pass through, and as franko6 said, it doesn't take much water to cause damage. This is because water is not compressible. If it gets all the way through the intake tract and into the engine, the engine sucks it in and then tries to compress it. When it doesn't, something has to give way and that is often the engine rod.

At least a turbo engine has a much larger intake tract than a non turbo and an intercooler to help slow how fast water can enter the engine.
 

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Is it possible to add a baffle or water trap? I suppose that if it were a good idea, VW would have added it or someone else would have already come out with this mod.
 
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