I tried to clean the intake manifold. I opened the upper plenum, the lower plenum. Everything was fine. But when I loosen the bolts for the intake manifold, there is a leakage. Lots of green fluid (coolant?) came out from the bottom of the car. I didn't figure out where it was from. I can see some liquid on the edge of the intake manifold where it contacts with the eninge. I have to tighten the bolts, leakage stopped. I cannot understand why. I am wondering if the fluid can go into the engine cylinder? If so, will it be harmful to the engine?
Thanks.

 

there is coolant flowing through the intake manifold. remove all the hoses before you remove hte manifold, and the fluid will run out on the outside of the engine. otherwise, you could get coolant inside the heads.
it's not TOO serious, but you need to remove all your spark plugs and crank the engine over for a bit before trying to start the car.

if you only got a small amount of coolant in there, you'll have nothing to worry about, but you won't know that until you fire the car up.

safest and easiest thing to do when you get it back together is to just remove the spark plugs and crank the engine over to clean the cylinders out. you'll be fine after that.

 

Thank you so much. I feel much comfortable now. I will try that right now.