overheating problems on mercruiser 470

[jecooper]

Hi, all, i have a sea ray with two 470 mercruiser engines and outdrives. the starboard engine has a heating problem, it seems i fried the impeller on the out drive, after i replaced it the heating problem began. I have checked the thermostat, it tested okay. i think the problem is my heat exchanger, i can not remove it without removing the engine, as the port engine is too close, so i can't get to the nuts on the u bolts. i have back flushed the unit, i did get a lot of small rubber pieces, i attempted to remove the end plates, i removed the 9/16 bolt, but can't seem to get the end plate off to examine the tubes, any suggestions on how to remove the plates without damaging the unit? I will be checking the riser, but i really don't think it is the problem. Any help will be greatly appreciated.

 

[Tacoma_Dave]

Did you inspect the water pocket cover when you replaced the impeller? I made that mistake my first time and had to open it back up. Won't make that mistake again. Heh.

 

[Scott Danforth]

the end plates are simply big stamped copper washers with a 3/8" bolt in the middle. between the end cap and the heat exchanger is a EPDM rubber sheet with a hole in the middle. the bolt also has an o-ring under it.

with the bolt off, take your pocket knife, and get between the end cap and rubber sheet. slowly pry until the end cap comes off.

new end caps and sheets available nearly everywhere that services heat exchangers.

 

[jecooper]

the end plates are simply big stamped copper washers with a 3/8" bolt in the middle. between the end cap and the heat exchanger is a EPDM rubber sheet with a hole in the middle. the bolt also has an o-ring under it.

with the bolt off, take your pocket knife, and get between the end cap and rubber sheet. slowly pry until the end cap comes off.

new end caps and sheets available nearly everywhere that services heat exchangers.

thanks for the info, when i attempted to take it off, i used a screw driver and a hammer to try to dislodge it, but it didn't budge, i didn't want to do anything else before i had a chance to talk with some one about it

 

[jecooper]

Did you inspect the water pocket cover when you replaced the impeller? I made that mistake my first time and had to open it back up. Won't make that mistake again. Heh.

actually i did, when i changed the impeller and housing, and still had the problem, i removed it "again" to inspect it to make sure i didn't fry another one, that is when i back flushed the system from the small cooler/heat exchanger, until i had a good stream of water coming out of the copper tube, inspected inside the housing, and everything looked good, thanks for the reply