Volvo 5.7GXI-F - Overheating

TitanBry77

Recruit
Joined
Jun 4, 2009
Messages
3
Hey all, I'm not sure if you remember me, I had the drive issue last season that required it to be pulled and worked on and then this seasons first outing got me the overheat and hydrolocked engine.

Well the hydrolock part has been resolved with new risers and gaskets.

Now the overheat problem will not go away, I have a 5.7GXI-F with the freshwater flush system. Then engine is raw water cooled.

I ran the engine for a solid time on the garden hose to get it to the normal operating temperature which is right about 175(F). On the hose it will never go over that.

So we loaded her into the water and let it sit at idle on the dock as I parked the truck/trailer. Already I noticed the temperature was rising a bit past the normal 175.

Idled out through the no wake and wasn't but 5-10 minutes before my temperature started rising, 200+ and then my overheat sensor began to chime.

As we idled back I pulled the various hoses from the sea water pump intake and exhaust and observed water flow seemed ok, also seemed to be flowing through the thermostat housing as well. I know this won't show any air being pulled in but water flow seemed adequate.

Got to the dock let her cool a bit, pulled the water pump off, impeller is in perfect shape.

I am thinking there has got to be an exhaust problem or an air ingress in the drive, I can't see any other reason why she runs perfect on the garden hose, soon as I put her in the water, no good!?

The oil level is perfect, still fresh clean oil from the winterize oil change, no signs of water, the levels are good. Pulled the block drains as good measure to make sure I had no clogs etc and was ok there.

What do I do now, I'm looking at pulling the Y fitting at the transom or pulling the drive off and looking for signs of air ingress??? I did have that drive issue last season that required a lot of work, perhaps the shop bungled a hose or something and it split over the winter.??

Any input is appreciated as always. Thanks guys
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Volvo 5.7GXI-F - Overheating

A couple of things come to mind. Do you have a NeutraSalt system on your drive? Probably not, but worth asking. The most obivous question is this. Is the cap on the flush hose on your engine tightened properly and not leaking. if it sucks air, then you will have an overheat.
 

P 0 P E Y E

Chief Petty Officer
Joined
Jun 3, 2009
Messages
441
Re: Volvo 5.7GXI-F - Overheating

Don S. has a good point. Check that first.

Check your circulater pump while underway...see if the big hose swells with excessive water pressure as you pick up the rpms. That would indicate a restriction in the water exiting

double check the belt tention and see if the circ. pump has runout at the pulley.

Take a long water break and recheck the stuff you looked at before. Sounds like your on the right track, just over looking one small detail. Double chck your math and do not assume anything.

A positve attitude does not effect newton and his darn laws.
 

TitanBry77

Recruit
Joined
Jun 4, 2009
Messages
3
Re: Volvo 5.7GXI-F - Overheating

Thanks guys, the freshwater flush cap is always tightened while underway, I am positive of that, checked it before.

While underway I didn't notice any swelling.

What would you mean and how to check the circ pump for a "runout" I do have a problem with the serp belt producing black residue/flaking off, I always thought that it could be condensation or moisture getting to the belt but there could be a problem here also.. hmm.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,563
Re: Volvo 5.7GXI-F - Overheating

Check your circulater pump while underway...see if the big hose swells with excessive water pressure as you pick up the rpms. That would indicate a restriction in the water exiting.
Actually, all the circulating pump does is circulate. It doesn't pump water out to the exhausts at all. Also, the big hose is on the suction side of the pump.
 

TitanBry77

Recruit
Joined
Jun 4, 2009
Messages
3
Re: Volvo 5.7GXI-F - Overheating

Ok I have been reading some of the documents and posts, I am going to start some testing this morning, hope I can find something, June and I'm still not in the water... uggggh!
 
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