454 Mercruiser Engine Problems
 

Alright...so I've got some problems with my 454 mercruiser, and it's frustrating :mad: . Basically, ever since i got it, the exhaust manifold's have been cracking every 2 years...which is not right. When i winterize it, i pull ALL the plugs (and i mean all the plugs). I usually poke around with a small screw driver or wire to get all the crap out until the water drains. I pull all of the hoses out of the risers, drain the water, and poor antifreeze through the hoses that supply water to them until the antifreeze pours out the exhaust. I dunno what i could be doing wrong someone help me :hothead:
$2k every 2 years is not a fun fee to pay...

I have the same motor. I hook ear muffs to the drive and run 3 or 4 gallons of RV antifreeze through the motor (until the antifreeze it spit out if the exhaust for a while). Then, I take the thermostat out, and fill the motor up until it runs out the pipes and replace the thermostat.

I bought one of the little self-winterizing kits from Boater's World.

Run 6 gallons ........ up through the whole system ...... 5 usually take care of it but 6 good insurance

Maybe if you watched a professional merc mechanic, you might see something you are doing wrong. I've read your other posts on this and if you"ve done evrything recommened I can't see why they would still be cracking.

Same answers :rolleyes: Not to mention, you can get used Merc manifolds all over for couple hundred bucks.
http://www.offshoreonly.com/forums/d...-problems.html

hehe, i know just seeing if i could get any other responses because i didn't know if i posed that in the right section :lolhit: . I've been thinking about replacing the manifolds myself but i have two problems. 1. I don't know how to, and 2. I don't want to replace them if they're just gonna break again. And @TSPM, after I'm done I've usually used about 5 or 6 gallons of AF. It's very frustrating and i don't want to replace them if I'm just gonna be posting here in another 2 years saying "they broke again".

If that's the case something is wrong elsewhere or it is not winterized properly. Buy the manifolds/parts and have them installed by a Merc dealer same with winterizing. We have sold and serviced numerous 454's and have had no issues.

I agree with TSPM, I have winterized hundreds of 454's and never had a manifold crack. I have replaced many manifolds for other reasons though, and the replacements last many years, even aftermarket. Something is wrong, where are they cracking? As far as winterizing, if you just remove the hose from the bottom of the manifold all the water will come out. There's nothing to freeze. When do you notice the crack, in the spring after the first startup? If not do you have good water flow?

Good point ........ do you have blockage in the flow system or ....... how is your water pump ....... if you have blown impellers your not pumping the non tox through the system etc etc etc ........ do your homework ........ there is something not adding up here.

one more point .... if you don't have a clue PAY and take it to a Merc Certified dealer for a complete inspection ...... they will find the problem if you can't ...... just some good advise thats all