5.8L Penta still wants to overheat on initial startup

[ferrall]

Almost everytime I put this thing in the water after having it sit over a day it just doesn't seem to want to circulate water and cool. I always end up pulling the hose from the p/s cooler to the t-stat housing at the t-stat housing and I get a big burp of air and water. I put it back on and it's all good to go and runs fine the rest of the day. It seems I'm getting some kind of air bubble or air lock everytime. What could cause this? The raw water pump impeller is brand new 2 days ago.

 

[cr2k]

Re: 5.8L Penta still wants to overheat on initial startup

I would back track from where you pull the hose and look for blockages. Possibly in the heat exchanger.

 

[ferrall]

Re: 5.8L Penta still wants to overheat on initial startup

That was my next step but I did do that last year when I sucked up sand but will do it again to eliminate it for sure. I still think there is some type of air lock though because last year I'd pull one hose off the impeller pump and put it back on and it'd be good to go as well.

 

[ferrall]

Re: 5.8L Penta still wants to overheat on initial startup

Ok, took the p/s cooler off and found 1 tube with a little stone in it and removed it but I know that wouldn't cause my problems so I took off the high pressure fuel pump and that some sand in it and so did the check valve from it to the t stat housing. Removed all the sand, made sure check valve works and then put it all back together. Started it up and it runs fine. Hopefully this is the end of the overheating.

 

[a70eliminator]

Re: 5.8L Penta still wants to overheat on initial startup

If your still having the problem on the initial warm up you should be considering a new T-stat, it may have problems opening past a worn spot or something of that nature, you could give a trial run without it installed just to verify the culprit.

 

[ferrall]

Re: 5.8L Penta still wants to overheat on initial startup

I did replace that already about a week ago and who knows, it could have been part of the problem. I don't think it's ever been replaced. Thanks!