I recently rebuilt the 3.4L engine in my '93 Camaro. I am experiencing several problems since the rebuild. The engine bogs on WOT from idle, there is a leak into the engine compartment when it rains and fills the crankcase, not the cylinders, with water. I really need to deal with the engine leak ASAP. I snugged the valve cover bolts again. A friend of mine said it might be the O-ring might be missing/broken on the distributer dummy shaft,,,dunno, thats a booger to get to. Any help will be appreciated.

 

You sure it is rain water? Also what is a distributor dummy shaft? You have a distributorless ignition.

 

The engine is in fact DIS equipped. The injunirzs at GM in thier infinate wisdom realized that they couldn't drive the oil pump because the drive gear was on the bottom of the distributer! So they probabley whacked the head of the distributer off above the top bearing...Viola!...drive assembly, oil pump (proper nomenclature) or laymans terms, dummy shaft. Yes it is rain water because the coolant level remains the same. I also covered the top of engine with a thick plastic contractors bag...the next rain there was no water intrusion. The water was laying on top of the plastic in small puddles. I don't even know how it's getting into the engine compartment. I could use some hep on this one.

 

Oilfill neck leaking or missing? I know water has a habit of sneaking in through the wiper cowl area. Have you gone out after a rain to see where the water was coming in at? Also, does this just happen while driving, or while it just sits during a rain?

 

if you are getting water into your engine compartment you should check you weather stripping on the back of the hood along the bottom of the windshield and make sure it is making some sort of seal, but if it is small amounts that might not be your problem...and also, when i rebuilt my 3.8 i was told to reset my computer...
if you havent already, i recommend it.
its pretty simple on our fbodies
1st access the fuse panel on the inside of the car and locate the PCM BAT and i believe it to be PCM IGN(not sure with ign..im 95%) but it is both that say pcm.
once you find them turn your key to accessory and remove both fuses and let sit for 5 seconds then turn the key to the off position(you can take it out but youll need it again)
after 5 seconds or so put the fuses back in and turn the key to accessory again.. let sit for about 30 seconds then start the car...
your Rpms will start out at about 500 and go up a little high but will level off... it may take a few start ups to get it to idle perfect right away but it will refresh your computer and wipe out any previous codes it was reading

 

I hate to resurrect a 5 year old thread but this is the ONLY place on the entire Internet where this problem has even been mentioned. And I have/had the same situation with my '99 3.8L Firebird.

After THREE upper intake manifold replacements and then a replacement engine that lasted 6 months before water in the crankcase returned I finally concluded it HAD to be rainwater getting in somehow since every occurrence immediately followed heavy rain. But I had refused to believe rainwater could find its way into the engine. The mention in this thread about the O ring seal at the unused rotary distributor casting at the rear of the engine was my "Ah-HA!" moment. But how was the water getting on the engine?

With the hood up and a garden hose flowing water down the windshield I discovered water pouring out from under the plastic windshield cowl where it's clipped to the firewall lip directly onto the engine on either side of the intake manifold. I popped the cowl loose and found two small pieces of rotten weather stripping in the center but no other waterproofing anywhere else.

Since I cannot get to the back of the engine my only recourse was to stop the water from getting onto the engine. I dried, cleaned and used windshield sealant to permanently bond the cowl to the body because the plastic body clips do not provide enough down force on weatherstripping to prevent leakage.

Apparently rainwater dripping on a hot engine while driving gets evaporated quickly so the oil contamination could not take place. But water dripping and pooling on a cold engine while parked was either seeping into the crankcase at the distributor seal or being drawn in by mild crankcase vacuum when the engine was started.

I now have to question all the alleged upper intake manifold gasket failures these 3.4L and 3.8L engines have a history of. It boggles my mind how many needless repairs and destroyed engines may have been the result of just poor GM body design and a bad casting seal gone undetected because nobody could wrap their mind around how rainwater could even remotely be the culprit.

My thanks to the OP and others here who helped me confirm an absolutely absurd and unthinkable condition and pointed me toward a solution. It only took me three top end tear downs, a replacement engine, about $3500 and finally a Google search to this thread to get to it. ~FH

 

remove the wipers and the cowl so you can get down to the metal part of the cowl. Use a garden hose and run low pressure water down the windshield, with the hood open and look in the engine bay do see where the water is comming in. If water does not leave the inside of the cowl then you need to clear the drain holes so the water can drain behind the fenders.

As for the water getting into your engine means a gasket is not sealing properly. I know Duh right? The gaskets are supposed to keep oil in but also everything else out. The gasket for the oil pump drive could allow water to get into the engine, and also the rear of the lower intake could allow it. I am going to put my money on the oil pump drive. It should have a little round gasket similar to what a dizzy gasket on a SBC looks like.

Massey

 

google is your friend. man what a nightmare. im gona check mine next wash job. i got water in my ecm somehow and have not been able to figure it out.

 

One of the areas water was dripping from the cowl was directly over my ECM, too. I'm surprised it hasn't fried. I cut a 12" X 18" square out of a neoprene sheet and made a raincoat for it just to be safe even though the cowl is now sealed. ~FH

 

i fried one and i think another just went. still figuring it out, not sure if its in the memcal or the main ecm where the rust was. lucky i have a few 93 ecms. well maybe only a couple now.