Upon installing the upper manifold gasket on my 2000 s-type 3.0 (6 cylinders) , I accidentally connected the vaccum line to the coolant reservoir. The car started up fine, but a couple minutes later, the car started hesitating and near stalling, I also heard a knock and quickly turned off the car. I noticed the coolant in the reservoir was missing coolant and got sucked in somewhere, I felt the vacuum on the reservoir cap.
I found out the vaccum line was connected to the reservoir hose. And the coolant line was connected to the vacuum in the throttle. I fixed the hoses and all the vaccum lines and coolant lines are now correctly connected.
Is it safe to start the car again? I felt like the car was dieing or ruined the cylinders? Should I start the car or is there something I need to check before starting the car? I checked there is no coolant in the oil dipstick or cap.Did any coolant get into the cyclinders? any help please?

 

Coolant, or water, does not compress. You may have bent a connecting rod if the engine is knocking.

I personally would not attempt to start the engine and would get the car towed to a competent repair facility.

 

Hmm, this is a tough one. Some coolant certainly would have made it into the cylinders. The big question is how much remains. If only a minor amount, this may not be a big deal.

I'd suggest first removing the three coils and spark plugs on the easily accessible side. Look inside the spark plug holes with a bright light. This should give you a general idea of how much to panic. If you see more than a few drops, remove the intake plenum and remove the coils/plugs on the other three cylinders. At the front power distribution box under the hood, remove fuse F5 (fuel injectors) and F12 (ignition coils). This lets you crank the starter without any fuel or spark. Any excess coolant trapped in the cylinders should blow out through the spark plug holes. Then spray a little light oil in each cylinder to help replace any oil that was washed from the cylinder walls.

If you find only a few small droplets in the first three cylinders, the other side is probably similar. Use a socket and breaker bar on the front of the crankshaft, and see how much resistance you feel while trying to manually turn the engine.

If there's not much resistance, hydraulic lock isn't going to be a problem. You should be safe to reinstall the plugs and coils and try to start the engine. If you'd like, you could spray a little oil in those cylinders first, but I'm not sure it would be worth tearing the other side apart.

If you do feel a lot of resistance trying to manually turn the crankshaft, you've probably got hydraulic lock on the other three cylinders, and you'll have to pull the big intake plenum to remove those three spark plugs, as detailed above.

Hopefully no other damage was done. I vaguely remember something about coolant can contaminate O2 sensors and catalytic converters. But if the engine only ran for a few minutes, you may be okay.

 

Thanks for the reply, I removed the first 2 spark plugs on the easy side and there was no coolant whats so ever. So I topped off the coolant and started her up. Alot of white smoke started coming out the back I ran it for a good 10 minutes and the white smoke didnt go away yet. I plan on starting it up tomorrow and see if it will burn off by itself. Any suggestions?

 

Quite possibly the engine has been hydrolocked. Remove all coil units and spark plugs then spin the engine with the starter to expel any remaining coolant. Reinstall the spark plugs and coil units then restart the engine. If the knocking is still present, the engine has been hydrolocked with one or more connecting rods bent.

 

If it started and ran OK, you have survived it, and it will clear. This could be water in the exhaust that needs to be burnt off. Just check all connections to make sure you have connected everything right.
I suggest you tighten up on your work process.

 

Did the engine make any unusual noises during this test run? Other than the white smoke, did everything else seem okay? (Other than that, Mrs. Lincoln, how was the play?...)

Most likely you've got some residual coolant collected somewhere in the exhaust system, probably in the cats. If just running at idle, the cats may not get hot enough to burn off that moisture. There's a potential the cats may be damaged by the coolant, but with little to lose, I'd suggest driving moderately for a few miles and see what happens once all is up to normal operating temperature. If you hear any unusual noises or the check engine light starts flashing, be prepared to turn off the engine quickly.

When you return from your trip, check for any OBD codes. If you get any new codes, it's possible this may have been caused by contamination of the O2 sensors.