Click and Clack — Tom and Ray Magliozzi: Water-logged engine could need rebuilding

Friday, Aug. 20, 1999 | 8:38 a.m.

Tom and Ray Magliozzi's auto repair column appears Thursdays and Fridays in the Sun. Got a question about cars? E-mail them by visiting the Car Talk section of cars.com.

My '94 Toyota truck drowned going through a BIG puddle. When I first tried to restart it the starter grunted and gave up. So I waited for everything to dry out. Unfortunately, it still does the same thing. Jump-starting doesn't help, and when I tried to push start it, the tires squealed because the engine was completely frozen up. Am I in deep doo-doo? Is it bad starter doo-doo or new engine doo-doo? The truck has given me no trouble until now. -- Chris

Tom: Oh, you poor guy, Chris. I think you're deep in new engine doo-doo.

Ray: Here's what probably happened. When you went through that "big puddle," water got sucked up into the engine's air intake.

Tom: The air intake normally draws air into the cylinders. But in your case, it drew water in. And once one or more of your cylinders had water in it the engine became "hydro-locked."

Ray: The way the engine usually works is that the pistons suck in air and compress that air. But water can't be compressed like air, so when the cylinders are full of water the engine just stops.

Tom: At this point there are two possibilities. One is that no significant damage was done to the head gasket, valves, pistons or connecting rods, and once you blow out the water, the engine will run fine again (you do this by removing the spark plugs, cranking it and watching Old Faithful shoot out of your spark plug holes). This is also known as the "you should BE so lucky" possibility.

Ray: The other, much more likely possibility is that you've already ruined the engine -- if not in the puddle itself, then by trying to jump-start and roll start it. And in that case, you're in for an engine rebuild. We wish you the best, Chris. And stay out of those big puddles in the future ... especially the ones that show up on maps.