Question on Temp Rise 2000 5.0 Mercruiser

[rick3452]

Hi guys, Serial # 0M012817 Half closed system with heat exchanger.
The other day I was cruising the intercostal with my family... I've had this boat 5.5 years and have put 1600 hours on it (now has 1800 hrs.) When I went to open it up within maybe three minutes the gauge went from the "constant " 160 to 180. I throttled it right back and within a few min, the temp returned to 160. This never happens... It had been 5 years and 1500 jrs since I replaced the Manifolds and Elbows so Yesterday I replaced both sides and took it for a ride. This time while running high RPM's it stayed pretty much at 165 but a few min later it rose to 170. So I brought it back and changed the Impeller including the new housing. There was 600 hrs on the impeller and it was completely in-tact I sort of thought that there may have been missing fins, but no. so when I take it out tomorrow and if it does rise.... What else should I look for? I have noticed on the Heat Exchanger hoses I have seen slight amount of green seepage.

Thanks as always for any help..
Rick

 

[NHGuy]

Well you could check the coolant and oil for contamination.
Might try some of that BG EPR stuff. It cleans everything especially the ring lands. But it could also make any other issues show up too.

 

[alldodge]

If it climbs back up, I would remove the end cap off the heat exchanger and see if it needs to be cleaned. If exchanger is good, and assuming you have a bravo drive, I would remove the hose coming from the transom to the seawater pump. In most cases the hole is clogging up.

 

[rick3452]

Thanks very much! Heat exchanger is clear no blockage at all. I'm thinking the last option is the Bravo clogged hose. Any thoughts on changing to a through hull sea water pick up????

 

[alldodge]

In most cases it's easier to fix the original fitting, but you can install thru hulls and strainers. This type

Or other thru hull and mount sea strainers

 

[rick3452]

Thanks really appreciate your input.....
Rick