hydrolock???

92 940 turbo 19t,greentops,tlao chips, 012 maf, do88 intercooler. I haven't driven this car in about 2 years due to a blown transmission. before that happened, I was having coolant loss/overpressure issues which I suspect was/is a leaking headgasket but never confirmed.

fast forward to now. I finally put a new transmission in this past weekend and drove a very short distance to verify the trans was good with no issues and it seemed to be. only thing I did notice was a high pitch noise (faint but noticeable) when in boost which im guessing is turbo related but didn't have time at the moment to investigate. I got the car insured and drove it to work today which was maybe 4 miles each way. the only issue besides the slight high pitch noise was that when coming to a stop from almost any speed the engine stumbled a bit but I assumed that it was just lh2.4 trying to relearn and was going to let it be for a bit to see if it sorted itself out

I drove to the junk yard after work and on the way home it was acting up when slowing to idle as mentioned. when I got closer to home it seemed to be having an issue getting into boost so I was easy on the throttle trying to get it home to take a look at it. before I got home the engine stalled and wouldn't even turn over. I checked the coolant and it was highly pressurized. I tried to turn it over after releasing coolant pressure and it was still stuck.

I walked home and got a ride back up with tools about an hour or 2 later only to find that the engine turned over/started easily and would hit boost no issue and had no concerning noises. I drove maybe 2 miles home and when pulling up to my house found that the engine was having issues trying to hit boost again. in neutral it wouldn't rev very high either and seemed to be choking. once shut off the engine wouldn't turn over again.


I am assuming that the headgasket has let loose and is dumping coolant causing hydrolock and preventing the turbo from spooling once enough coolant is in the cylinder. would this be plausible? ii will do a leakdown test but would like opinions.

thanks for reading and feedback

Did you take out the plugs yet?

no checking yet as it was late when i got the car home. I will be digging into it tomorrow

Your logic is sound but I haven't heard of anything this specific previously in all honesty.

If it helps... you can get one of the USB or cell USB boroscopes off Amazon for not a lot.

The other thing I think might be worth considering is a stuck valve? I'm just trying to think of things that would cause an odd yet dysfunctional amount of pressure to essentially lock the piston in place...

Plus side... the trans is good!

Hydrolock usually screws up the connecting rod...not good!

Usually happens by ingesting water on a high-compression engine.

Good Luck!


Dave Riedle

Firmly clogged cat?

The only time I've seen hydrolock is from some doofus in a Jeep going through a wide stream over-and-over again. He got some impressive rooster tails of water before dying mid-stream. The engine still turned over but wouldn't start.

If you've got enough water going into the cylinder to hydrolock, I'd expect some big time misfires on that cylinder before that point.

muppetman342 said:

I'd expect some big time misfires on that cylinder before that point.

Click to expand...

And a LOT of smoke.

Maybe some animal moved in while the car was sitting