Volvo Penta 5.7 temp at trip's end

[tkrfxr]

Twin OSXi-DF 5.7 L engines run at 175 deg., the stbd engine temp rises to 200, while docking, at the end of the trip....runs 175 while on plane...

I flushed the engine with a garden-hose at the end of the trip, and the temperature went down to 175....

Where do I start? The impellers were new this spring....The port engine is fine....

 

[Don S]

Re: Volvo Penta 5.7 temp at trip's end

I would sure recheck the impeller before going on to anything else. All it would take is a plastic bag to damage an impeller.
Could also be a partially plugged heat exchanger. Have you pulled the end caps and checked them lately?
If that checks out, you may want to pull and inspect the risers for plugging. That model was used from 03 to 05, so it's getting close.

 

[tkrfxr]

Re: Volvo Penta 5.7 temp at trip's end

I will start with the impeller. While I am at the raw water pump, is there any way to see if the incoming water is flowing properly, like a vacuum pump?

I can probably flush back with a dockside water hose, but I'd like to know if the forward flow is adequate...

I noted the top cap of the heat exchanger was hotter than usual... certainly hotter than the port engine. But it cooled off when flushed with the hose.

I will have to see if the manifolds' water flow is unobstructed....by removing the drain plugs while flushing from the pup hose...

 

[Don S]

Re: Volvo Penta 5.7 temp at trip's end

Your drive may look a little different, but the same basic troublshooting is needed.
Have a look at this overheat diagnosos.

http://www.4shared.com/file/50572185/e88f1d89/Volvo_Penta_Overheat_Diagnosis.html

 

[tkrfxr]

Re: Volvo Penta 5.7 temp at trip's end

Yup!

that's what I'm looking for...


Thank you.

 

[tkrfxr]

Re: Volvo Penta 5.7 temp at trip's end

I have gone through the diagnostics in the VP file. So far, I have done th following:

1. Checked the impeller - it's new.
2. Inlet hose to raw water pump: clear to and from the oil cooler hose
3. Outlet hose to heat exchanger: clear, flushes through to the manifold drains
4. Heat exchanger: top and bottom caps off, cleaned, washed, flushed clear
5. Inlet from transom assembly: flushed (boat is in the water)
6. Assembled and tested: 175 at engine, risers get very hot...200+

7. Connected water hose to engine flush adapter, risers cool down, turn off the hose, risers heat up....repeatedly and reproducibly...107 deg with hose on, 150+ with hose off

Sounds like I have yet to test the following:

-inlet hose from xdp drive to transom shield - must haul out for this....or try connecting the raw water inlet to the port engine's inlet with a hose and test at the dock.....
-engine flush hose (never had a problem here before...but could leak air in)
-obstruction at the risers/manifolds, but both?

I will test some more tomorrow...

 

[tkrfxr]

Re: Volvo Penta 5.7 temp at trip's end

Beware! Beware...of things connected to the cooling system after the manufacturer's delivery!

I listened to the engine as I started to flush with the garden hose, and I heard gurgling in the rear, as if air was being pushed out by the pressure of the water...I traced the connections and noticed the NeutraSalt flush hose entering the power steering cooler....the hose goes out away from the engine and into a solenoid valve that opens on command from a helm switch...the hose was disconnected....I do not use the system because I noticed blue flakes in the port engine riser and heat exchanger last spring...the hose was leaking air into the raw water intake hose through the power steering cooler...

As soon as I connected it to its solenoid valve, the engine ran perfectly and the risers stayed warm to the touch.....

Lesson of the day: Beware of loose NeutraSalt hoses going into your cooling system!!! They can cause sucking of air and overheating of the manifolds and risers.

 

[bruceb58]

Re: Volvo Penta 5.7 temp at trip's end

I don't know about yours but my NeutraSalt System has stainless steel clamps holding them on. Do yours?

 

[Don S]

Re: Volvo Penta 5.7 temp at trip's end

One other note on the NeutraSalt system. Those electric valves can go bad and stick open. Once the NS liquid is gone, it will suck air. Even at idle.
When I had my Volvo, I installed a small ball valve between the engine and the NeutraSalt valve just to prevent it happening.

 

[tkrfxr]

Re: Volvo Penta 5.7 temp at trip's end

I don't know about yours but my NeutraSalt System has stainless steel clamps holding them on. Do yours?

It does now!

Thanks for the reply....I might just set up the system again, just to make sure it functions properly....

 

[bruceb58]

Re: Volvo Penta 5.7 temp at trip's end

I like Don's idea of the valve. I once was messing around in the engine compartment and broke one of the fittings off of the valve. I ended up just pulling the hose and butting a bolt in it until I could get a new fitting put on.

I really think the NeutraSalt system is worth having running.