So I decided to follow a honda civic through a flooded road in my '93 850...dumb move, i know, i thought about it, and decided to do it anyway.

Long story short, car is dead. Pulled it out, got it to start. Towed it home due to soaked air filter, loud knocking. White smoke from exhaust (likely H2O).

Started it once more and drove it into garage.

Drained oil (was a milky brown color, almost like chocolate milk)...filled and drained 2 more times. Changed filter, filled oil. Took apart air box and vacuumed out any remaining water. Removed hose to engine body, this was dry. New air filter. Added dry gas to fuel tank. Pulled out spark plugs, appear to be OK.

Car is throwing code A6, 3-1-4 (typing from memory, but absent camshaft position sensor signal). Reset code. Code isn't reappearing, but car isn't starting.

Car is currently in garage, drying out.

Thoughts? Help?

I don't believe the engine seized, there wasn't a shudder or shake when it stalled. It just died, no smoke.

Thanks,

~Jon

Try a compression check. Hope you didn't bend a rod.

How well is a compression check going to work on a cold engine? Seals seal better when warm.

The cylinders being equally cold you could make a comparison. You can also squirt some oil in each cylinder and see what that does for compression.

If you did manage to get water in a cylinder, The engine would just stop turning. No shudder, no jerking, no vibration, nada. The fact that you were able to restart it with a severe knock and the oil got water in it means that one piston is totally dead.
The CPS sensor will not allow the engine to restart if the ECU doesn't get its signal. This can happen when it is wet or the Tbelt slips a few teeth.

If water did not get into a cylinder, wait a day or 2 to let it dry out.

Klaus
--
Just driving a 1998 V70R :)

I do water crossings all the time, but in a purpose built vehicle. When wheelin' you can search out muddin' spots or water crossings, but you do so with full knowledge of the consequences.

I do a lot of wheelin' in my '97 TJ (Jeep Wrangler). Its currently got 31s on it. I've measured the height of my AEM intake (I don't use a snorkel even for water crossings) and I can ford a steam almost two and half feet deep safely.

However, water crossings are never a particularly good idea. In a car, or any other low ground clearance vehicle, the vehicle will tend to float as soon as the vehicle gets in water deeper than the pan. Literally the car will lose all forward traction and most of the time will have to be abandoned. Now in a Jeep blasting through a mud bog before becoming completely stuck is half the fun. Attempting to gauge the depth of a river or stream is always interesting. There are plenty of videos of folks who guess wrong. Then again my jeep comes with drain plugs in the tub, cars don't.

Playing in water and mud is an expensive hobby. In a jeep, at minimum it requires changing the fluids in both differentials, and the transfer case. I run Mobil 1 75w-90 synthetic in my Dana 30 and 35 and Mobil 1 ATF in the NP231 so a single water crossing costs me $25 minimum. Water and mud will severely shorten the life of your hubs and the constant velocity joints (as found in the Volvos). It will also destroy the cooling fan of most cars as the blades impact the water. On a purpose built four wheel drive the driver will specifically replace the mechanical fan with an electric so as to enable the fan to be turned off for water crossings.

What you did is referred to as hydrolocking your engine. An internal combustion engine compresses the air-fuel mixture and ignites it with a spark, a diesel relies on the compression alone to ignite the mixture. To a large degree an internal combustion engine is just a glorified air pump. However, water can not be compressed. Its a fundamental principle of hydraulics. Liquids don't compress. At the bottom of the deepest trench in the ocean a cup of water is the same amount of water as the water at the surface. No matter how many atmospheres of pressure (or ft/lbs if you wish) you push on a liquid with it ain't gonna compress. The pressure will compress anything else though, this is how hydraulics work. You push on one end (Brake Master Cylinder) and the brake fluid can not compress so the pressure gets exerted on the other end, to the brakes.

When you sucked water into your intake and your pistons attempted to compress and ignite the air fuel mix, bad things happened. Water doesn't compress, so something had to give. That thing was your rings, rods, pistons, cam, crankshaft...

I'd expect you're looking at a complete rebuild if you had any considerable amount of water in your intake at all.

If you are about to pull water into your engine, you should ALWAYS turn it off before water gets pulled into the intake. That way you can just pull the plugs later and turn the engine over. with the plugs out the engine can't Hydrolock. You can then throw some Marvel Mystery Oil in there get your plugs back in and drive away...you'll smoke for bit, but you won't be looking at a rebuild.

On that note, a dirty secret of rebuilds is that your machine shop and mechanic can NEVER rebuild an engine to anything close to the tolerances of a factory engine. Many ethical mechanics will advise their customers to order a remanufactured engine, as they can't in clear conscience bill them to rebuild the engine at the same price point, or anything close to the same quality of what can be produced from a dedicated engine remanufacturing facility.

Now that being said a lot of people enjoy rebuilding their own engines. My sister has done a couple of air cooled Volkswagon 2.0L engines. She knew she couldn't put together anything close to what GEX could do, but she enjoyed wrenching and learnin' how to do it herself.

Volvos are pretty simple mechanically. Salvage yards are full of Volvos with good engines in 'em. If you are going to do it yourself get a good cherry picker. Don't ever trust the two by four in the garage or the multiple guys lifting approach.

Good time to swap out your engine mount rubber while you're in there.

Wow, tough luck. You have done all the right things to recover. All I can add is check and clean electrical connectors. One by one take them apart, spray with contact cleaner, and reassemble. Make sure the ground cables (the braided wire cables) are tight and clean. Battery OK? Just keep drying the engine area with heaters and a fan. Hope it goes well.

OK...so it's alive and running now. no codes, white smoke is gone...oil still has some water in it, so i'm going to flush through again...

however, the idle is jumping between 800 and 2200...thoughts to check? my first thought is vacuum lines, going to run through those tomorrow. anyone else have any good ideas???

Great news.

Check for water in the vacuum lines and the hose that goes to the air pump under the front fender. A small hole drilled into the cold air pump at the bottom and a corresponding one a little higher up will let water out.

Check the idle air control motor hose also, but it should be dry.

Klaus
--
Just driving a 1998 V70R :)

either I'm missing something or the car is, I can't find an air pump, its a non-turbo model (shouldn't matter)

I ran along all the vac lines, didn't find anything...pulled out the idle air valve, no water in there - is there a way to test this to make sure it is functioning and not stuck?

the idle speed has moved it is now between 1500 and 2000 and when you put it in drive and are stopped it idles above 1K and you can feel it rearing to go...could the throttle be stuck open?

The air pump is only active during cold start, until the engine warms up. Look for a 1" hose that goes from the air cleaner down to below the left headlight. Access to the pump is from the bottom, infront of the wheel well.

With the idle that high, check all vacuum connections around the intake manifold. Include the vacuum tree next to the throttle body.

At least it is running... When you drive it, avoid short trips, you want the engine to get up to operating temps to help evaporate any water.

Klaus
--
Just driving a 1998 V70R :)

I've been running it up to normal operating temp, then opening up the oil cap to let any steam escape. the seal is shot here, so i need a new gasket.

I haven't been tkaing it out of park because of the idle, with foot on the brake and in drive, the idle is up near 1200.

I followed the instructions on bay13 for air pump removal. There is no 1" hose going from the air box to below the left headlight. Out of the airbox I have hte large hose to the Throttle Body and the intake hose from near the radiator.

I'm going to go out and visit my favorite dealer for TB gasket and remove the Throttle Body and check that.

You are very lucky no major dammage was done!!! my 95 N/A 850 didnt have an air pump either!! It may be a good idea to ckeck / clean the flame trap. Also with it running at idle ( whatever speed it is at for now)you can spray carb cleaner at all vacuum hoses and around the general intake area, if there is any sort of vacuum leak it will either make the engine rev up or sputter and drop speed, this is a sign of a leak. the water may have caused a line to pop off or crack maybee a bad intake manifold gasket. good luck keep us posted

I'm looking at the idle air controller, I don't believe it is closing/opening all the way, when you pinch the outlet hose off of the IAC the revs drop. I'll try the carb cleaner around the vac lines.

So I pulled the IAC out of the car today, soaked the inside with CLP (WD-40 with teflon), and started beating on it with a hammer. I loosened the valve a little, repeated, idle is stable around 1200 RPM now...off to the junk yard tomorrow to find a replacement tomorrow...what years/models are compatible with the 93 850 NA.

Thanks

~Jon

I believe all IAC motors are the same for 850s. An idle of 1200 means that you are still getting too much unmetered air into the manifold.

Klaus
--
Just driving a 1998 V70R :)

so the IAC fixed that problem...sounds like something is rubbing along the belt or belt driven. sounds like a bearing rubbing or similar high friction on a rotating surface...

In order to find out what is making the noise, I use a long stick. Be careful of the belt! One end of the stick pressed up against the cheek bone near your ear, the other on the engine part. That will easily locate it.

Klaus
--
Just driving a 1998 V70R :)