Volvo Penta 5.7Gi Closed Cooling Question

[MalibuMike]

the outdrive

the raw water fitting under the upper transmission where the raw water hose is.

look at the manual.

item #9 in the image below

Item 9 was replaced when I did the bellow service. Thank you for taking the extra time to post an image with your advice!

 

[MalibuMike]

Took the boat out today to do a little more investigating. Ran it to 3200 rpm then ran back to the manifolds and risers to check temps. The top of the riser was warm to hot but I could see amy hand there for 10 to 12 seconds without worrying about burns. Feeling the sides, I could find a few spots that were hot but maybe only 5 degrees more than the top. The manifolds felt warm and I was surprised that they were cooler than the risers. Laser still shows about 158 to 160 at the thermostat. Keep this in mind, that the laser therm alway reads about 15 degrees lower than the gauge.
Since I dont know the boats history, I decide to call a local mechanic to makes an appointment to have the risers inspected. When he asked what was going on I explained to him that the boat idles in the harbor around 165. and runs at 178 under cruise around 3000 rpm. Coming off cruise, the needle might rise to 180, but then backs down to 176. It will back down even faster if I start to slowly cruise at around 1200 rpm I think due to the impeller spinning faster. His response was that 170 to 180 was perfectly normal and the sweet spot for Volvo Penta. He said when you start hitting 190 or 200 is when you have a real issue that needs immediate work. He said it was safe to still run it, but since it was used boat, I might want to change the manifolds, risers, and impeller to put it on a fresh new maintenance schedule. Might gut tells me that I'm getting close to needing the manifolds and risers serviced but that I'm still ok to run it for a little bit ( maybe 4 weeks). Mechanic also offer to swing by the boat and hook up the diagnostics to see if there were any issues and I think he said to see what the temps have been running at or if there was any history of overheat alarms. Here is a video of the needle moving around under cruise and them backing down.

 

[jerryjerry05]

IF?? the manifolds are fresh water cooled? then
keep them and change the risers.
Pics of the setup??

 

[Lou C]

The Volvo manifolds can’t be set up for full closed cooling. So if replacement is needed you’re replacing the whole thing. $725 or so Barr aftermarket for the whole kit. Just put a better coat of paint on them first. I think the OP’s running temp is a bit higher that what you see with raw water cooling but a closed system will run a bit warmer than raw water cooling. Look at the spark plugs for any sign of corrosion on the electrodes. Remember it’s not just the issue of clogging causing hotter running it’s the issue of water possibly leaking in after shut down. That will cause rusted exhaust valves and valve sticking/rough running.

 

[MalibuMike]

Just read this in the manual "
Temperature Gauge—Indicates engine tempera-
ture. Normal operating temperature for all engines
(except 8.1 Gi & GXi) is 155°-178°F (68°-81°C) and
135°-158°F (57°-70°C) for the 8.1 Gi & GXi. Engines
with closed cooling systems will typically run about
30°F (17°C) higher."

 

[Lou C]

Your temps in the vid really didn’t go over 175* even after you slowed down. I’m surprised that Volvo says that the temps of 30 over what’s normal for raw water cooling are expected I’d have thought more like about 180. Ok so your temps appear normal it may look high because of the gauge used where 160 is in the center. Some gauges put 175 in the center and if you had one of those it wouldn’t seem high to you. So if your engine temp doesn’t really exceed 175 and the exhaust doesn’t overheat after slowing down (ie not exceeding approx 160* or so after coming off plane) then that’s good. My only concern as I said is the possibility of seawater leaking around the joint between the manifolds & elbows and corrosion causing a rust through.
With raw water cooling and the same manifold design and thermostat housing my engine runs at 160 and will only rise to 170 after slowing down after coming off plane. The hottest the manifolds and elbows ever get is about 135. But with closed cooling I’d expect both to be a bit higher as normal.

 

[MalibuMike]

Well, I wasn’t brave enough to start taking off the riser or the manifold but I did remove the rubber coupling just to get a look at the condition of the iron to see if I could figure out if these things were a year old or a few years old! Here are some photos but unfortunately I did not get anything good looking down the throat. Since I have no basis for what normal might look at over a period of time, can anyone give me an idea if these are a few years old or 4 to 5 years plus?

 

[Lou C]

It’s hard to tell from pix but try tapping them with a small hammer, if it makes a sharp ring then they probably are still solid, if they make a dull thud with flakes falling off they need to be replaced.

 

[MalibuMike]

A quick update and there are more details at the other thread I have going
I finally pulled the manifolds and the risers. Was going to use them but then saw to many signs that they are failing. Order two new manifolds and already have two new risers. It just wasn't worth the risk! Also going to clean the heat exchanger now that I found it fairly easy to pull the manifolds and risers.

 

[MalibuMike]

I don't think Volvo offered full closed cooling in that year range because of the design of manifolds, there are only 2 low mounted ports for fittings on the manifold front and rear, not a low mounted one and a high mounted one like on a Merc manifold. You need a high and a low mounted port to allow antifreeze to circulate without air locks and hot spots. This engine likely has raw water cooled exhaust manifolds & elbows.
It depends on the water the boat was used in but if in salt water these exhaust systems have to be checked and possibly replaced every 5-7 years or sooner if you see water leaking from the joint between the elbows and manifolds. Volvo had trouble with their original gaskets and updated them some years back.

View attachment 331716

Lou- These OEM riser gaskets look a lot different than the Sierra ones the shop sold to me. I think the OEM's are the way to go and this is one repair I dont want to use Sierra ones on. Seems like Sierra makes some good aftermarket parts but there risers gaskets are not anything like these.

 

[Lou C]

agreed use the Volvo OE ones and do check the mating surfaces as described above & use a torque wrench....
next time use Barr Marine...cast in USA and their gaskets are good...

 

[MalibuMike]

Wanted to share a quick update. I finally assembled everything today and did a 30 min test at the boat ramp dock. I ended up doing the exhaust manifolds, the risers, the impeller, the circulation pump, the heat exchanger, and the thermostat. Started it up and quickly found one small leak at the rubber coupler on the exhaust but no other leaks were found. Even with rpm's held at 3000 , I never went above 165. I know I need to do another test under way but so far the temps are down and the risers are cooler than before.

I have a feeling the local boat parts place sold me a 160 thermostat when I told them I have a 1997 Gi-f. This may have caused some confusion. I now have come to learn that I have a 2006 Gi-F motor with a closed cooling system. The manual shows this below.
Thermostat- 5.7Gi-F,5.7GXi-G:66°C(150°F)VolvoPenta PN3587597
Closed Cooling System Thermostat 5.7Gi-FF, 5.7GXi-GF: 77°C (170°F) Volvo Penta PN 3831426. Closed cooling heat exchanger mounted on engine
Any advice on running the 160 or should I install the 170?

 

[Lou C]

Honestly I don’t think it will make much difference. One thing I’d suggest is:
Before running it up on plane make sure to bleed all the air out of the heat exchanger. I like the Lisle radiator funnel, this gadget makes it easy to bleed cooling systems without spilling antifreeze all over the place. I’ve used it on vehicles with great success.

 

[MalibuMike]

Honestly I don’t think it will make much difference. One thing I’d suggest is:
Before running it up on plane make sure to bleed all the air out of the heat exchanger. I like the Lisle radiator funnel, this gadget makes it easy to bleed cooling systems without spilling antifreeze all over the place. I’ve used it on vehicles with great success.

Thank Lou! I removed the expansion tank from the bracket and held it as high it would go when I added coolant. I likely filled it too much since it went well above the "max" line and dripped for a while out of the little hose attached to the barb opposite the cap. After running it for a while the level never really changed. I also removed the cap a few times while it twas warming up and when hot.
Are there any other tricks about bleeding air out of the system?

 

[Lou C]

Usually what will happen is that some trapped air will exit when the thermostat fully opens, and it may have if you ran it at 3000 rpm in neutral a the dock. Does your heat exchanger have a removable cap on it? If not then the way you did it is probably fine. If it does have a cap I'd let it cool and remove the cap (never remove when hot, its under quite a bit of pressure like a car radiator) and see if its full. If so fine replace the cap if not just top it off and replace the cap. I have seen Volvos with no cap on the exchanger but the pressure cap is on the expansion tank. In that case you have to bleed it out using the expansion tank. And running it at higher than idle rpm the cap off the expansion tank to allow any trapped air to escape might be the way to do it.
The thing is you don't want air pockets in the engine or heat exchanger because this can slow down coolant circulation and create hot spots, which will cause borderline overheating.


I went on the European VP site listed in the mystery engine thread to try to figure out your cooling system. And its a bit different than the aftermarket ones available here in the USA. The aftermarket H/Es sold here use a pressure cap on the H/E. On the Volvo OE closed system, No pressure cap on the Heat Exchanger and the expansion tank has the pressure cap on it. So, I'd run the engine with the pressure cap off the expansion tank, at the dock, above idle speed you don't see any more bubbles appearing in the tank. Then replace the pressure cap. The idea is you want 100% liquid in your cooling system.

 

[ripjmk]

The cooling system details on the European VP site have to be matched to the engine model. The heat exchanger is only applicable to the 5.7 Gi-FF, not the 5.7 Gi-F. This means that this engine was supplied raw water cooled and must have had an aftermarket fresh water system added to it at install.