1989 Mustang 5.0 GT Engine watersoaked after 3 days of rain and under carport

When I went to start the car the engine was bucking the starter, ran for 2 seconds then died. Tried a few more times and the same thing. When I opened the hood there was not one dry spot anywhere, water beaded everywhere. Even the serpentine belt was soaked. The intake plentum was soaking wet being flat on top. We had 3 days of on and off rain and fog here in Florida and temps in the low 50’s. Today back near 80 and no rain.

Now the car was under the carport and not run for about a week so the car never got wet. I pulled the rubber cover off the distributor and was wet on both sides. I popped the distributor cap off and water droplets on the inside. I wiped everything off and engine did crank better but when it started, it started shaking and died. I went inside and got 2 window box fans and laid them on top of the engine running full blast for about an hour, and then it started and ran fine. Shut the hood and let it idle for about 20 minutes as the heat of the engine would dry it out faster. Took it for a 45 minute ride and no problems.

The carport base is cement and a metal roof. What I noticed was, everyplace else was dry under the carport except where the car was parked, just a lot of moisture bumper to bumper. When I opened the hood it looked like it was hit with a garden hose and it was not a prank as I have a secondary hood lock on it. What in the world would cause this severe moisture build up ? Never seen anything like this in 45 years of driving.

It’s environmental and involves the dew point in the atmosphere. You can do a net search for a technical explanation of how that works but it basically involves the amount of moisture a certain volume of air can hold.

That happens quite frequently where I live here in OK as it’s usually quite humid and sometimes it looks like the engine bay just came out of the carwash with the hood up.
It does saturate the engine electrics and can get inside of the distributor cap.

It wouldn’t be a bad idea to spray the coil, distributor cap, and plug wires down with WD-40 or something like that as it can help repel moisture and prevent misfire problems.

Thanks, I just picked up some WD-40, the cap and wires were replaced about 3 years ago. Will go out tomorrow and spray. The way that engine was fighting the starter was afraid I would bend a connecting rod like the engine was hydro locking.

I would go to the dealer and pick up a new cap and wires. Some of the aftermarket stuff just doesn’t hold up. I had a 72 Chevy that needede a cap a year before I got smart and put a good one on.

I just replaced the plugs rotor , cap and wires 3 years ago and only put 4k on the car since then, as it does not get driven much.The entire engine was water soaked like ok4450 described, like going through a car wash with the hood open. I have never seen this before, just like driving your car through a flood. Everything was soaking wet. Just had this weird weather event as I had the car since new and only 114k on the clock.

Why was the entire car port be “dry” except where the mustang was parked ? It was wet bumper to bumper on the ground cement., After I got it running and pulled the car back on the lawn to keep the exhaust from entering the home with open windows near the carport it dried out with the heat from the engine.

I was thinking of doing what you say, but when an entire engine looks like it was hit with a garden hose and shorting out the secondary ignition firing the wrong cylinders. I had primary spark as when I would crank it, the tach was reading 300-350 rpm from the ignition module…Still open to comments here and thanks so far for the replies. Its been a few hours, and the stang cranked right over and no rain here in FL for at least another week. In the summer we have thunderstorms just about every day where it is humid and never a problem with that. Been in FL since 1991.

It’s not a matter of quality on the parts; it’s all about the dew point and the right conditions. As you have discovered, the moisture even makes it’s way inside the cap no matter what.

I’ve gone out multiple times in conditions like this and even found the insides of headlamps saturated. It looked like someone had been hosing those off from the inside.
This particular problem has been solved by opening up the lamps with vent holes on the bottom.

This kind of thing also affects cars that appear to be dry when the hood is raised. Someone shuts a warmed up engine off on a humid evening and the heat pulls moisture inside the distributor cap, plug wells, etc and which then cause an engine miss.
It’s the same principle as a window sweating on a cold, damp day.

+1 FOR OK4450 Totally agree been doing some research on this

The cause is the same as all condensation. When warmer air with high relative humidity comes in contact with a cooler surface, the boundry layer can no longer hold the water vapor and it deposits it on the cooler surface. Water molecules attract one another, which creates the condensation. With very warm air, the humidity level can get very high, and the condensation can be surprisingly high. Very warm air can absorb and carry a lot of water vapor. Fluctuating air pressures can also drive that air, with its humidity, into the tiniest of orafices. It gets into everything that isn’t very well sealed… as in hermetically sealed.

For preventing its condensation on surfaces, I prefer silicone to WD40. It repels water without any solvent. It won’t keep the water vapor out, but it’ll tend to keep it from condensing on the surface so much.

OK4450, talking about headlamps, I noticed moisture in the left headlamp…going to drill a small couple of holes in the bottom base of the outer enclosure tomorrow…What you said is 100 % True you know your stuff Thanks…Howie

I found that drilling a small hole at the bottom and another at the top took care of moisture in headlight housings. The accumulated water quickly drains from the bottom while moisture will escape from the top when the light is on and hot. Be careful where you drill. A missplaced hole might worsen the problem.

Your car was cooler than the air, and the air had close to 100% humidity. When that warm very moist air passes over the colder parts of the car water condenses on the surfaces of the parts. In this case you got all the conditions in an extreme way. The carport kept the car cooler and allowed air to circulate bringing in more moisture. This kind of thing happens more commonly with marine motors. High moisture at the dock since you are sitting in the water and even more moisture in the engine bay due to the bilge water sitting in the bottom of the boat.

I’d consider a new cap since any internal arcing of electricity will leave carbon “tracks” making it easier and more likely for arcing to occur in the future. The wires should be OK if you clean them with alcohol and let them dry.

+1 to the same mountianbike totally agree and learning a lot…Thanks