Question:

Why is the coolant leaking out of my 470 mercruiser, and where is it coming from? p?

by  |  earlier

0 LIKES UnLike

after rebuilding the carburetor on my 470 mer cruiser the coolant started leaking out. i have never had this problem. does anyone know where it wld be leaking, or why????

 Tags:

   Report

4 ANSWERS


  1. Try this. Take and sqeeze both the radiator hoses at the engine and at the radiator and see if you see any coolant. It could just be running off of a leak at one of the hoses and running down the block.


  2. Could be coming from a lot of things. Not really enough information to make a determination here.

    Is it leaking only when running or just after stopping the motor too.

    Likely causes at the back of the engine would be: cracked block, freeze plug leaking, cracked exhaust manifold, leaking exhaust hose and/or leaking water inlet hose.

    There are a few other things it could be, but these are the most common.

  3. the bottom?

  4. I've disliked the 470 (3.7L MerCruiser) since I got into the boat business over twenty years ago, only because of this problem. More than likely, it's the donut gasket on the back of the heat exchanger (that big, long cylinder-shaped object on the side of the engine). Now, because that donut gasket in the back is probably bad, you'll want to replace the front one as well. It's easier to replace the back one if you remove the whole heat exchanger, but it can be done while it's still in the boat. Just remove the bolt that holds each cover on (one for each side) and then pull the gasket off. Take a scraper and get all of the old gasket off, then take a little sandpaper and sand it down just a little bit so that the gasket adheres well, put the new gasket on, and tighten the cover back up. Don't hammer it on really tight, but it needs to be pretty snug. I would always keep a spare set in the boat with a wrench in case you need to replace them out on the water, mainly because that's the most common problem with that engine. Don't forget that you'll now have to fill the coolant back up by filling it on top of the exhaust manifold...just put a little bit in at a time and then start the engine, let it run for 20 seconds or so, then fill it up, start it again and let it run for a bit, then fill it again. Do that process until the level of coolant doesn't recede, then you should be ready to go. Good Luck!

Question Stats

Latest activity: earlier.
This question has 4 answers.

BECOME A GUIDE

Share your knowledge and help people by answering questions.