Do you have a stock air cleaner? I would guess it is coming into the motor thru the Air intake.

Most people think that if water get pulled into the intake it will destory the motor. No it wont as long as the motor can pull mostly air in around the water the water will not hurtt anything. Once past the throttle body the water is exposed to vacuum and turns to a vapor. At the right ratio it can even make you car run better.

The amount of water you are talking about I believe it would have to be drawn into the crank case not just fall or leak in. So now we are talking about the clean air feed for the crank case ventilation which uses filtered air from you air clean drawn into the motor from infront of the throttle body. Since the air flow is in front of the throttle body it never turns to a vapor and would be sucked into the crank case. If you where getting small amounts of water at a time, with the oil being 220 degs the water would just turn into steam and flow out through the PCV system.

You can forget the dummy shaft seal your car does not have one. As for mechanic replacing intake it is very easy to tell the differents between water and coolant. Coolant will destory a motor. It becomes a acid under pressure and it mixs with oil. Water will seperate and show a level of water and a level of oil. Water is not good for a motor it will not trash it like coolant will.

 

hmmm, I saw this thread the other day and tested it today before I washed my car and sure enough the water comes down off the windshield and, almost like nothing was in the way, starts pouring all over the engine...guess i'll be fixing that.

Gorn- what kind of things will happen to the engine when water gets drawn into the crank? would it make it more difficult for the oil to lube the engine, making for more wear, until it burns off?

 

You oil has three main jobs. Lubricate, Hydraulics and heat transfer. Water would be weak in the Lubricate/Hydraulic areas. If you cycled a lot of water through the motor I would expect the lifters to complain first. Also your oil pressure would drop off very quickly.

If you are not getting a drop in oil pressure or any valve tapping I doubt you are running a high percentage of water. The big risk is over filling the pan. Pans are designed to have about 1 qt extra of oil, after that the level will rise to be in the area where the crank spins. The crank will become a mixer and the whip the oil and water into a frothey mess. In will introduce air into the mix. It is the air that does the damage. The air hurts the ability of the oil to be a hydraulic fluid (to create the fluid bearing). It will no longer create pressure. This is also true if you just over fill your oil with oil.

Water getting TO the engine can be a lot more common then you think. Even in my 96 I had an issue with the car missing in hvy rail. I noticed the water was pooling in the lower intake. I sprayed the coil packs and plug wires with “wire dry” like the off road guys use and the issue went away. That was 2+ years ago. I think your issue is less about how water got around the motor and more about HOW it got inside the motor. Due to emission requirement motor are built to be air tight. You should be able to poor a bucket of water on your motor and it should not get inside of it. If you plug up the Crank ventilation on a high miles motor she will blow out the weakest gasket. As I stated before the intake for the crank ventilation is in the air intake. Everything that enters your motor should be doing so through the air cleaner.

In theory you could plug you crank ventilation and see where the motor vents pressure. The down side to the theory is if I am right and the water is coming into the motor by the hole you just plugged you are going to blow out your weakest gasket and most likely end up with a bad oil leak.

 

This is definitely a rainwater event and not water being ingested through the air intake. You can drive this car through a hurricane and get zero oil contamination. The air filter and snorkel remains clean and dry. The problem ONLY occurs when the vehicle is parked in a heavy rain and THEN driven afterward under clear blue skies. Just a reminder: this car had no oil contamination for 6 months during the dry season when it did not rain at all here. The same was true with the engine I replaced. No rain, no water in the oil. There is no smoke or steam in the exhaust at start up. No water getting into the cylinders.

You are correct there is no dummy distributor shaft or seal on this motor. I had to go to the junkyard to look at one and verify what I was seeing on the on-line exploded engine diagrams since I can't get to the back of my motor. There is also NO fresh air crankcase ventilation. It's a closed electric EGR system with no physical connection to the air intake at all.

But what this engine DOES have is front and rear oil galley seals where the lower intake manifold mates to the heads and block. A compromised rear seal would give ample opportunity for water to either drip into the crankcase or be drawn in by vacuum when the engine is started and water drains back off the upper intake with acceleration.

When I had this problem with the original engine and first started suspecting it might be rainwater I would physically inspect the oil after a rain event before driving and find it to be uncontaminated. But after as little as 20 minutes of driving under blazing sunshine the lifters would start to chatter. I'd stop, pull the dipstick and find the oil had turned to latte but volume was no higher than the FULL mark. Drain, flush, replace oil & filter and everything would be fine... until the next heavy rain. And now the exact same scenario has occurred with the replacement engine. And I'm not running any commercial coolant mix. Just water. And there is none missing from the cooling system. It remains full and clear.

The original engine had 197k when removed. The replacement engine has 118k on it. For BOTH to experience the same failures under the same (heavy rain while parked) conditions cannot be coincidence. IMO, it points to a commonality; a compromised crankcase seal and water shedding across it somehow.

It's possible the oil galley seals may be prone to failure on all these vehicles. But as long as you're not allowing water to pour onto the intake manifold and run off the back you may never experience rainwater oil contamination.

Since I sealed the plastic windshield cowl to the firewall and stopped water from shedding directly onto the engine there have been several serious downpours here. And so far there is not the slightest hint of water in the oil after being driven.

I will definitely keep this post updated about whether the "fix" continues to work or if the failure returns. ~FH

 

All cars have a PVC (Positive Crank ventilation ) system. They all require clean air to work. No manufacture I know of pull unfiltered air into the motor. Why do you think there is PCV valve? You car does have a EGR (exhaust gas recirculating) system. The only thing those two systems have in common is that they are required by law to be there.



I have no idea what is causing your issue but two main facts are true. (one)Your V6 should run under water as long as the intake air supply and exhaust can breath as designed. If it did shut down it would be due to electrical issues not water in the motor. Remember oil seals are good up to 80 PSI. Some of the gaskets would fail well before that but not at near zero pressure for sure. (two) what ever problem you are having is not common issue. The fact you have had 2 engines do the same thing tells me the issue is not the engine. It is something on the engine. I am a GM cert master tech and I have worked on cars for 30 years, I have never seen or heard of rain water in a motor unless it was flood car. I have pulled motors out of junkyards out off cars with no hood and not had the issue. Many junk yard store motors outside and just duct tape the intake and exhaust close. I have also been helping people with V6 on this forum for the last 4 years and I have seen some really oddball stuff but yours is the first complain like this. Water in the PCM is fairly common.

Your fix is a band aid. Yes if you keep water away it can not get into the motor but it is just a matter of time before water gets to where your issue is.

 

I think I may have confused your initial explanation regarding the PCV valve...
I erroneously read that to mean there was an air source for the PCV pre-throttle body. Upon re-reading it I now know what you meant, since the PCV valve is capped and in the upper intake manifold air stream.

I certainly appreciate your expertise and contributions. I am not certified to do anything except fly planes and drive 18 wheelers. I've only been wrenching my own motors for over 40 years. And until the Firebird I had no experience with the trials and tribulations of the 3.8L. That's why I took it on good faith from the certified mechanics at the licensed shops I initially took it to the problem was either intake manifold or head gasket related. As previously explained, multiple repairs resulted in multiple repeat failures. And now a similar failure with a different engine... a complete long block not cobbled together.

As I said earlier, with either engine the vehicle could be driven in blinding downpours without ingesting any water whatsoever.

Of 1 thing I am now absolutely certain. This IS a rainwater dripping onto a cold stationary engine followed by then starting and driving event. Sealing the windshield cowl to the firewall, being subject to multiple daily deluges and then driven with no more subsequent oil contamination further confirms it as a rainwater event.

As you correctly state, it's now a matter of determining HOW rainwater is getting into the engine under these circumstances. I could only surmise, as other previous professional opinions wrongly insisted it could only be coolant from bad intake/head gaskets, it must be the rear manifold seal being corrupted and drawing in water as it drained off the running engine. Far fetched idea among experienced professionals? Yes. Impossible? No. But your comments about the PCV system has pointed me toward re-examining the one on my Firebird. And it shares a commonality with my odd-ball leaking real manifold seal idea.

The PCV valve on my 3.8 is under a metal cap on the top of the passenger side of the upper intake manifold. I have now read multiple reports of other 3.8L owners during routine replacement of the PCV valve finding the gasket under the metal cover plate completely disintegrated. And the PCV valve cover is directly under the leading edge of the windshield cowl... right where it was leaking the most rainwater on the engine.

This is indeed true. A new PCV cover gasket or a bead of RTV sealant might have been enough to cure the problem. And I intend to reseal that cover plate at my next opportunity. I probably should have suspected that before conjuring up the idea of a failed rear manifold gasket. But I was still struggling with the whole concept of rainwater getting into the engine that no professionals would remotely consider. In either case my best immediate option was to get the windshield runoff shedding somewhere else instead of directly on top of the engine. And, still failing to find positive proof of gasket corruption, it has worked so far. I'll seal up what ever I can and keep on motoring.

With a tip of my hat to the professionals who supply so much helpful information to us shade tree guys here, I can only add that sometimes absolutely absurd conditions like mine can defy tried and true problem diagnostics. And it doesn't get much more absurd than rainwater in the engine. ~FH

 

or the ecm. im with ya bud. i know one rule on the boat i learned early, keep water away from motor. lol.