300m water noise

coming from under the dash on acceleration, any ideas?

 

Air getting into the cooling system, and goes through heater core. Is
it running hot at all?

(Just went through this a couple months ago, but on an old M-body....)

 

seems to be running ok

 

You need to bleed the system of air. Make sure coolant pressure bottle
is filled to the MAX line (don't remove cap on warm or hot engine),
start it up, let it warm up to pressurize the system, turn it off. Open
bleeder (on top front of engine - looks exactly like a brake bleeder).
Air should come out at first. When you see a steady stream of water
come out, close the bleeder. Check level in pressure bottle and top it
off again, if needed, after it cools down.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Hopefully there's not a problem that is putting air into the system (bad
gasket, water pump leaking causing low coolant and air in system, etc.)
and a one time bleeding will take care of it. If it continues to
happen, then that will have to be investigated, but you need to do the
initial bleeding to see where you are (i.e., to see if it recurs and/or
look for leak).

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

thank you, I will let you know

 

just as you said, thank you so much

 

You're very welcome!

Visit the 300M Club and forums when you get a chance:
http://300mclub.org/forums/index.php?sid=426876de8fc01e7e267dc347d2afee34

Questions like yours specific to 300M's and other LH cars are asked and
answered daily there.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')