Should i worry about hydrolocking the engine?
 

My friend and I have been working on very similar jobs on our vehicles: replacing the injectors. I just heard from him today that he was working on it (a 1988 Toyota 4Runner with the 3vze) and turned the engine over twice then it hyrdolocked. He then was able to get the water out but caused an engine fire that destroyed some of the electronics. Needless to say it was a bad day for him. He says that he thinks water got into the open intake ports during a recent rainstorm even though he had the hood closed. I am a bit concerned about this myself because my car has been out in the elements with it's hood secured but the intake manifold is off. Should I worry about possible water intrusion into the engine compartment that could have gotten into the intake or injection ports? I Is there any procedure I could follow to expel/drain any water that could have possibly entered the engine?

Could I turn over the engine with the injectors out like I have asked about before (to get carbon shavings out in that case)?

Before you put your injectors back in, crank the motor a few times. (I would do this just to spray out any debris) If you see water coming out crank it a few cycles until nothing comes out.

YES!

if you have had a vehicle out in the elements with the intake off, and the hood open, you CERTAINLY have water sitting on the pistons.

how long has it been like this? water hydrolocking is not the biggest concern... RUST in the cylinder is!
you need to remove the injectors, or the glow plugs, and rotate the motor by hand from the front crank bolt, and verify it's not seized, then spin the motor with the starter if it is ok. this will expel any water sitting there, and lube the cylinder liners a bit.

He said the hood is secured but the intake manifold is off. I think this means the hood is closed.

Yes it is closed. I wasn't concerned about that until my friend said he got water in his engine compartment with the hood closed although that is a 4runner and not a W201. I would never leave the hood open when it was raining especially if the intake was off.

x2, if you want to go super duper squirt a little MMO in each cylinder before spinning it over by hand.

on the toyoto the hood is not sealed to the firewall like the 201 is. I highly doubt any rainwater got in with the hood closed...

Hydrolocking is, of course, possible - but it's darn unusual. If you have a concern roll the engine over with the glow plugs out just to ease your mind but it's unlikely. Following the cranking procedure I'd do a squirt of WD40 or similar in each bore just to be sure. Costs nothing and can't hurt.

Dan

Little bit of a hijack, but if you dont mind, i am particularly concerned with this when submerging mine, (603, will be in a Land Rover). Obviously there will be watertight intake boots, and snorkel, pcv fittings, egt is capped, and now im worried about the small vent hole in the rear of the valve cover also. Anything i've missed?

I'm not familiar with the 603 but in general be sure to remote the entry of ANYTHING that might get wet - valve cover breathers, etc. etc. I'm thinking out loud here but I wonder if you could fill the engine with smoke (maybe thru the dipstick tube) and see where it comes out. Anything that leaks smoke would let water in. The engine HAS to breathe but you can get the access to air above the point that would likely be under water.

This reminds me - you'll need to extend the dipstick tube and make a longer dipstick, too - I understand that this is often overlooked.

Dan

The dipstick tube and stick on the MB Diesels usually seal tight against each other, especially with a new Oring. I had several leak over the years, so replacing the Oring makes a nice tight fit to hold in the oil, and water out.

EDIT: I would be more worried about the turbo and air cleaner drain back tube seals.....Rich

Dipstick tube is something i overlooked. I guess my biggest concern now is submerging my hot #14 cylinder head into cold water! O_O