What is a Hydrolocked Engine?

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For as long as I've been working on vehicles(ShadeTree), I have only heard the term "hydrolocked" but, I don't know if I have ever had a hydrolocked engine. This is the reason that Im asking... Car is an 06 Mazda3 w/2.0 auto tranny

My daughter, who lives and works out of town, came home to visit this past weekend. Each time she come home to visit, I look over her car and check out things as she uses her car for work. Last time she visited, I changed the oil/filter and this time I gave it a good bath and vacuum cleaning.

After washing her car the other day(Saturday), I started the engine quickly and shut it down as I heard the phone ringing. I usually take the car for a quick ride(maybe get gas) and then return home. This time I shut off the engine almost as soon as I started it(ran for < 5 sec). I never restarted her engine as my phone call was rather lengthy.

In the late morning(Sunday) as my daughter's car was loaded and she was ready to drive back to her home, the engine wouldn't start. The starter was turning slowly but continuously. Sounded like the engine had some drag on it. She tried starting the engine a couple of more times and I had asked her to stop! We waited a couple of minutes and I myself tried to start the engine and, as the engine turned slowly, it sounded like it wanted to catch and it did finaly.

Started, and now ran fine like nothing was ever wrong. I took the car for gas and returned back home, all the while everything was normal! I shut off the car in the driveway for about 10 minutes and my daughter got in and started the engine like normal. She returned to her home without issue. She'll see this morning(Monday) if the engine starts with out issue. My question is; does this sound like the engine was "hydrolocked"? Any other questions you guys may have, please ask!
 
Hyrdolock means liquid has entered the combustion chamber, and because liquid does not compress, the engine will not run. Someone please correct me if I'm wrong, but if your daughter's engine was hydrolocked, it would not have run at all.
 
Hydrolocking usually occurs when a car is driven through deep water and it gets sucked into the intake and then into the engine. The locking occurs because water doesn't compress. I've never had this happen, but from what I hear, bad things happen, parts bend and so forth -- nothing that fixes itself by letting the car sit. So in my uneducated opinion, I don't think that's what happened to you.
 
Well, it took a while to get started and the exhaust smell was a bit strong but, no smoke that I noticed. Does this mean that if an engine is hydrolocked, it will never start without repair?
 
I think you flooded the engine but starting and shuting down immediately. Slow cranking may have been the result of some computer signal. Now that it is running, it should be fine.
 
If you truly hydro-locked the engine you'd know it, as someone else mentioned bad things happen. My bet is as Boomer said it was flooded, and will be fine.
 
I hydrolocked the 2.5L in my Jeep a month ago in Moab, UT when I rolled over. Cylinder 4 filled with oil and it wouldn't crank (I anticipated this and fortunately only burped the starter instead of hard cranking).

I simply pulled the spark plugs and cranked it over to get the oil out. I swapped plug 4 and 3 (4 was obviously oily)and she fired right up, with a Batman smoke screen.

I think you might have just fouled the plugs a little with the short start you had. It should be all cleaned up after a highway run or two.
 
Thanks all for the quick replys!
Yeah, it was cranking slowly like the cylinders were full(fuel mayby), no compression.

Other responces are still welcome. I need to feel better!
 
Originally Posted By: Zaedock
I hydrolocked the 2.5L in my Jeep a month ago in Moab, UT when I rolled over. Cylinder 4 filled with oil and it wouldn't crank (I anticipated this and fortunately only burped the starter instead of hard cranking).

I simply pulled the spark plugs and cranked it over to get the oil out. I swapped plug 4 and 3 (4 was obviously oily)and she fired right up, with a Batman smoke screen.

I think you might have just fouled the plugs a little with the short start you had. It should be all cleaned up after a highway run or two.


Yes, my daughter has an hour & a half drive ahead of her. This should help bring things back to normal. Im feeling a bit better after each post.
 
Originally Posted By: Boomer
I think you flooded the engine but starting and shuting down immediately.

My wifes car, her last car, and to a lesser extent, my current truck all do this. (All fuel injected)
I'll just put the pedal to the floor and crank them until they start to clear the flood and immediately let off when they fire up.
I try to let them run at least 20-30 seconds if I start them.
Originally Posted By: Char Baby
Other responces are still welcome. I need to feel better!

This is normal for most modern cars.
 
river_rat,
When I started the car, I too put my foot to the floor and away she went(finaly). I wasn't sure if "flooring" the gas while starting an EFI engine does anything these days. I almost started pumping the excelerator peddal(yeah, like this is going to do anything) but, then she started. :)
 
Originally Posted By: Char Baby
river_rat,
When I started the car, I too put my foot to the floor and away she went(finaly). I wasn't sure if "flooring" the gas while starting an EFI engine does anything these days.

The owner's manuals on all these said to do that. It still takes a bit of time to start them.
Anyway, I wouldn't worry about it.
The computer shoots a bunch of extra fuel to start, and if you shut down and let it sit, you have to vent that out out before the mixture will burn. On a cold day, it takes longer to evaporate that extra fual charge than in the summer, but it'll start in a minute or two and be fine.
 
Really sounds like a weak battery. With winter coming on, better check it.

A bad head gasket can allow water into a cylinder. The starter may be able to push it out the exhaust or somewhere and the engine start. Not sure exactly what did happen, but the car did start with great clouds of sweet white exhaust.
 
Originally Posted By: labman
Really sounds like a weak battery. With winter coming on, better check it.

Agreed
 
I have had an engine hydrolock due to a bad fuel pressure regulator. The regulator was vacuum operated, and when the diaphragm ruptured, the pump forced the fuel into the engine through the vaccum line.

Sometimes it would lock, others it would start and run, although not well. Very puzzling symptoms, at first. The reason it would sometimes run was that the engine had sat for a while, long enough for the gas to leak down past the rings.
 
A bad fuel injector can also hydrolock an engine by filling the cylinder with gasoline.

My son hydrolocked my Accra by driving through a water backed-up storm sewer. It bent engine parts and never started again. It was totaled under the comprehensive part of the insurance.
 
I agree with what everyone is saying about the fuel and your rig being flooded because you only ran it a few seconds, and that it ran well after it got started. I'd still get that battery replaced.

Technically ( because you asked what it is ) hydrolocked means water locked, but we all use the term loosely to mean any kind of fluid, even gas or oil. Hydraulic lock would be more accurate in those cases.
 
+3 on labman, check that battery. There is no way the computer or anything else can slow down cranking.

The factory air intake/filter setup will protect your engine from washing damage. Typically tons of bends and a "suck upwards thru" filter.
 
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