transmission won't engage

Hi this is my first post.
I'm French speaking so I hope that I will be explaining this well.
We purchased an older car in good working condition (Mazda 626 hatchback 1991) Last week our son in law said he could replace the antifreeze and clean the rad.The rad was still a bit warm so he said he could cool it down and he decided to hose it down(by now you guys have realize we don't know much about cars!!) After he was done with this mess my husband try to back up the car and absolutly nothing was moving.It started fine and the gear box was working but it would not move in any gear.We had to tow it back home and being both retired we can't invest a ton of money in repairs but if you have some ideas of were to start looking it would be much appreciated.
Thank you
Carole

I take it this car has an automatic transmission? If all he did was change the coolant (even hosing down the outside of the radiator) there is no logical reason for the transmission to not engage. I would suspect that possibly the transmission shift linkage has come apart. If you put the car in neutral can it be pushed?

If this car has a manual transmission, then possibly the clutch is shot. Or, if your son made that big of a mess he somehow got coolant all over the clutch and it won't grab.

Also, not to pick but this Forum is for the Chevrolet Camaro's and Pontiac Firebird's.
For Mazda specific information try here http://www.automotiveforums.com/vbulletin/forumdisplay.php?f=294

Thanks I'll move this post to Mazda,
To answer you yes the car can be push in neutral, and he sprayed more than the rad. water was sprayed all over.
Thanks
Carole

he sprayed more than the rad. water was sprayed all over.
Thanks
Carole
That is never good thing. Modern car engines, unlike the engines of the 70's and before, are VERY intolerant of water on them/their sensors.

No you are right this one is certainly allergic to water.
I forgot to mention the car as an hold mode it seems that it stops the action of the automatic speed change mechanism and that Hold light was flashing,which the book says it could mean that it's an electrical problem.
Thanks for making an effort to help I appreciated
C.

Interesting, I rinse motors off on occasion and have found the newer engines to be better at dealing with it than older ones. Granted if there is an underlying problem that has not really shown itself yet, this will bring it out. I find newer engines to be more weathertight in general than the older ones. My rules of thumb when doing this are: Let the engine cool off before rinsing, Do not do it while the engine is running, Do not use a power washer, Let the engine drip dry for a few minutes prior to starting again, Let engine run with hood up for 10 min or so to allow engine to heat up and shed moisture without it being trapped under hood, then go for a ride.