5.7 Volvo Penta Overheating at Idle

[ddbyrd3]

I had a similar problem with my 02 VP GL-b. My impeller housing was so wore. Once I installed a new impeller pump housing, my overheat at idle issues went away. I actually replaced the entire impeller assembly, new housing, bearing assy, pulleys, ect.

 

[baker7007]

When you replaced the rubber grommet in the lower drive did you replace both and inspect the Bronze (copper) tube? As I had this same problem of overheating only at idle.

Yes copper tube was ok.

 

[baker7007]

When you replaced the rubber grommet in the lower drive did you replace both and inspect the Bronze (copper) tube? As I had this same problem of overheating only at idle.

I also did water test - sealing off drive water intakes with water hose to impeller intake hose- to rule out leaking nipple. I had no drips coming from drive area whatsoever.

 

[Lou C]

OK then that's good, no leaks, for overheats at idle I'd be looking at the impeller housing itself. One time I sucked up sand and with my Cobra the impeller looked fine but the wear plate was scored and wouldn't pump as well as it should at low speeds. New impeller + wear plate and all good again. I try to stay out of the shallows but given my mooring area its hard to do.

 

[baker7007]

OK then that's good, no leaks, for overheats at idle I'd be looking at the impeller housing itself. One time I sucked up sand and with my Cobra the impeller looked fine but the wear plate was scored and wouldn't pump as well as it should at low speeds. New impeller + wear plate and all good again. I try to stay out of the shallows but given my mooring area its hard to do.

Thanks @Lou C !!! It’s an 05 so I’m doing water circulation pump too. We’ll see what happens when I take it out tomorrow.

 

[Tharding]

Not sure if this helps but I once replaced my impeller with a non OEM version and it was about 1/16th off in height (barely noticeable). As such, it would not create negative pressure to move water into the motor. Replaced with an OEM part and it was fixed!

 

[Lou C]

I always use OEM impellers even though I usually have to order them for my OMC.

 

[baker7007]

Not sure if this helps but I once replaced my impeller with a non OEM version and it was about 1/16th off in height (barely noticeable). As such, it would not create negative pressure to move water into the motor. Replaced with an OEM part and it was fixed!

I pulled a Johnson out of it but went Volvo Penta for new housing and impeller. Hoping this works!

 

[bruceb58]

All those pieces that are under water...if you are only overheating at idle, they aren't your issue.

The volvo manual states that you should remove the hose feeding the thermostat and you should have an inch of head at that point with the hiose vertical. mercruiser actually ahs a test where you allow it to fill a bucker for 30 seconds and you measure the water.

 

[baker7007]

Does anyone have any experience with the circulation pump? When I pulled mine off it’s fun freely like a wheel. However the new one that I purchased had a slight resistance/felt nice and “tight”. Could the old one I’ve been bad?

 

[alldodge]

I doubt the old one is bad. The new one has new seals and fit tighter on the shaft. After 100 hours or so it will spin easy also

 

[dypcdiver]

I am right behind alldodge. Over time I have replaced the circulating pump twice and they both circulated well, but they started leaking from the seal which threw salt water all around the engine compartment by the pulley.

 

[baker7007]

Turns out it was the hose going from oil cooler into transom. Anyone have a utube on how this is changed?

 

[baker7007]

It’s #19

 

[Lou C]

I’ve done it (Cobra is the same as the Volvo) on my boat there is an access panel that is above the back of the engine that comes off so you can get at it.

 

[baker7007]

I’ve done it (Cobra is the same as the Volvo) on my boat there is an access panel that is above the back of the engine that comes off so you can get at it.

Is the “oil cooler” an engine oil cooler or power steering oil cooler? I’ve seen both online. Does this serve as a heat exchanger to warm sea water before it goes into the impeller?

 

[dypcdiver]

Easy enough to get at on mine, I remove it every time I replace the Trim Sender.

 

[Lou C]

It’s a cooler for the P/S system. The incoming seawater cools the P/S fluid. Most of these engines don’t have an engine oil cooler; this is why a heavier weight oil is recommended than what’s typical for auto use.

 

[bruceb58]

It’s a cooler for the P/S system. The incoming seawater cools the P/S fluid. Most of these engines don’t have an engine oil cooler; this is why a heavier weight oil is recommended than what’s typical for auto use.

Depends on the year and the engine model. My Volvo Penta 7.4L had an oil cooler. I actually had to change mine since it leaked and I lost all my engine oil.

 

[baker7007]

Depends on the year and the engine model. My Volvo Penta 7.4L had an oil cooler. I actually had to change mine since it leaked and I lost all my engine oil.

2005 5.7 GXi-F