Volvo Penta 2003 (non-turbo), Overheating?

[DougR]

If, after trying all the flushes, coolant ratios, and plugged exhaust elbows, the engine still runs hot at high RPM, check the impeller in the fresh water pump. Early versions of this pump had a plastic impeller and it could slip on the shaft at high loads.

DougR

[Paul L]

Don't remove the thermostat. The opening of the tstat redirects the flow away from straight through, so removing it works opposite of what you think. At least that is what an old Volvo mechanic told me.

Doug, I didn't know that the FW pumps were actually rebuildable.

[DougR]

Yes there is a rebuild kit for the FW pump. Used to be part #876270 and then changed to 3812230. Don't know if it is still available .....

It contained the shaft and bearings, seal, impeller etc.

DougR

[Paul L]

There used to be a guy on the east coast that did the rebuilds of the FW pump. He made it out like it was really tough to do it yourself and the results often were not good. I ended up buying a new one.

[Capt Ben]

I've made great progress however I'm still not sure that everything is operating correctly. Specifically, I'm now wondering if the Circulator pump is operating up to par. When servicing the system, Volvo states that one should not allow this pump to run dry. That implies that it may not be self priming. I removed one of the feed hoses to the pump (the hose that goes up to the reservoir) and placed the open end into a bucket of water. With the engine running, there was no draw down of water, no suction detected. However, when the hose is positioned in its usual position (vertical) and if I pour water into the hose, the water is immediately drawn down. It seems to me, that as long as there is fluid in the reservoir, the pump will operate but at higher rpm does it need more volume than it can passively bring in?

I was able to eventually get the block drain to run freely. Now, after a second flushing, I've put a 50/50 mix back into the system. Allowed the engine to get nice and warm at a robust idle of about 1200rpm. The following are IR temps that were obtained while the engine was running at an idle.

Temps at: Idle well warmed up.
T Stat housing top:227
Circulator Out to House tank: 135 @ fitting
Circ out to Block pipe: 170 @ block
House Return @ Block: 150
Exhaust elbow top: 103
T Sending Unit block: 194
Head near Injector: 265-235
Oil temp once extracted : 154

TStat rating @ 74c

Do these numbers seem in range? The Volvo tech at Penta told me the temp sending unit should overtime out at 194F which is just what I was reading at the sending unit without overheating.
I'm also wondering, which TStat I should have installed in my engine. It looks like there are two available, one for the fresh water cooled, one for the sea water cooled. I find this confusing as I have both fresh and sea water cooling. See attached spec sheet. So, which system do I have?

[Paul L]

Use the freshwater t-stat

[Capt Ben]

Thanks Paul. That's what I've had installed.

Do the operating temps seem reasonable?
Do you or does anyone know if the circulator pump should draw without a gravity feed? Is there a way to verify that this pump is operating correctly? No leaks are evident.


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[deblen]

You have the "fresh water" cooled VP 2003 like mine. This means the antifreeze/water mix just gets circulated by a Volvo made pump @ lower stbd front of eng.,around & around thru the eng. & heat exchanger.
The heat exchanger acts like a car radiator. Instead of air,it uses "Raw" sea(lake) water,pumped by the bronze Johnson pump at lower port front of engine, from your raw water seacock,thru heat exchanger & out thru the pipe entering the front of ur exhaust riser elbow & thence out the exhaust.

Excellent suggestions by previous posters: I will add the following:
Raw water circuit:
Check for collapsing suction hose or "air" leak between Seacock & RW pump inlet.
Check oil in transmission for water as the RW passes thru a cooling coil in it.
Check exhaust riser elbow for scale build up in raw water passages-a common problem.Use new gasket.
Check Exhaust hose for internal collapse.
Remove & clean out Heat exchanger-for this you should have end cover gaskets & piping seal rings for both ends of any piping you disturb. Use Vaseline to inst. new seal rings. Make a new piping retainer for the 2 tubes that go in front end cover of HXchgr.
Cheers/Len

[deblen]

http://www.bluemoment.com/manuals/vo...002_worksh.pdf

http://www.bluemoment.com/downloads.html Parts exploded view

[Capt Ben]

Deblen, thank you for the info.
The water output is great, always was good, after cleaning strainer it's a bit better.
It's my hope that the flushing of the block and fresh coolant/water, and a new tStat has solved the overheating.

Do the operating temps seem reasonable?

Do you or does anyone know if the circulator pump should draw without a gravity feed? Is there a way to verify that this pump is operating correctly? No leaks are evident.


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[Emmalina]

When I had mine it started to overheat turned out to be a calcified lump in the gearbox cooling pipe.. Took ages to find it !

[deblen]

Originally Posted by Capt Ben

Deblen, thank you for the info.
The water output is great, always was good, after cleaning strainer it's a bit better.
It's my hope that the flushing of the block and fresh coolant/water, and a new tStat has solved the overheating.

Do the operating temps seem reasonable?

Do you or does anyone know if the circulator pump should draw without a gravity feed? Is there a way to verify that this pump is operating correctly? No leaks are evident.


Sent from my iPhone using Cruisers Sailing Forum

I've never checked mine with a gun,but ur temps appear OK to me.
I instd a temp & oil pressure gauge in mine along with the existing idiot lights & alarm.
The circ pump would not lift very far,if at all.It is designed to push water thru block same as on a car.The header tank provides make up coolant & should be kept filled to line mark on side of tank.
It would be difficult to check it's output since it is all piped. I suggest that if the bearings are still tight(remove alternator belt) it's probably OK.
Rebuild kits are $$$ as are most VP parts.
As another poster said,you should re-build your weeping RW pump-parts cost $150 or so & not difficult.
If you start working on the piping on this engine,you may as well order an assortment of the various seals used. This series is notorious for leaking water pipe seals-they dry out with age. Just use new ones with a little Vaseline.Also,use a round brush(a battery terminal brush) to clean the sockets that these pipes & seals go in.
Mine is a 1984 with 2100hrs. I removed the head & had valves ground last yr,as it was getting hard to start & that cured it.Other than external "wear" components,I have had no problems with it.
I have learned a lot the hard way so glad to help.
Cheers/Len

[DougR]

The fresh water pump will not pull water out of a bucket for two reasons:
- Circulation pumps will not self prime if they are dry, no centrificalpump will
- if the cooling system is full of water already, there isn't any place for the pump to push water to...

I think the temps which you have recorded are too high, specifically the head and thermostat housing.

Your system operates as follows: when the engine is cold the circ pump pushes water from the pump to the cylinder head via the lower of the two pipes going to the head. Because the thermostat is closed, the water returns to the pump via the upper of the two pipes ( return pipe) on the front of the head.

When the thermostat starts to open, the block off plate on the bottom of the thermostat begins to close off the opening to the " return" pipe and begins to direct flow into the thermostat housing and hence to the heat exchanger. After traveling thru the HE the coolant returns to the circ pump and starts its trip over again. When the thermostat is fully open no water travels out the return pipe and everything goes to the HE.

The temp of the thermostat housing should very closely follow the temp of the water flowing thru the thermostat. If the housing gets to 227 degrees, either the thermostat isn't opening, the return pipe isn't being blocked off, or water can't flow thru the HE. Use your heat gun to check the temp of the water pipe into the HE and the water pipe out of the HE. The water into the HE should be maybe 195 degrees max, and the water out of the HE should be about 20-25 degrees cooler. Did you clean all the green slime out of the HE?

DougR

[Capt Ben]

Emmalina,
Thank you for the suggestion. I haven't checked this area yet. Do you recall which of the cooling pipes had the blockage, in vs out?

Originally Posted by Emmalina

When I had mine it started to overheat turned out to be a calcified lump in the gearbox cooling pipe.. Took ages to find it !

[Capt Ben]

DougR, thank you for the concise description of the system operation.
Yes, she's still running to hot and tends to boil off coolant. I have not removed and de-calcified the HE. I have removed the drain plug on the aft end and water comes out with pressure and good flow. Oh, and there was no green slime or anything odd that came out of the HE drain. I can easily rest my hand on the HE even when the engine is HOT.

As noted earlier, I have changed the TStat. I guess there could be some kind of blockage in a pipe but that seems unlikely. I guess it's also possible that my new TStat is defective. I guess I should try placing it into a pot of water and testing it to verify opening temp.

Next time I'm at the boat I will verify the temps of the HE return and feed pipes.

So, it seems to me that the problem isn't in the exhaust elbow (which I haven't disassembled yet) and that the problem lies somewhere in the coolant side of the system. It seems that the seawater isn't being sufficiently cooled by the coolant water (HE). BTW, this has been a freshwater (Lake Michigan) boat since I bought her 15 years ago. She was previously a blue water boat.

Originally Posted by DougR

The fresh water pump will not pull water out of a bucket for two reasons:
- Circulation pumps will not self prime if they are dry, no centrificalpump will
- if the cooling system is full of water already, there isn't any place for the pump to push water to...

I think the temps which you have recorded are too high, specifically the head and thermostat housing.

Your system operates as follows: when the engine is cold the circ pump pushes water from the pump to the cylinder head via the lower of the two pipes going to the head. Because the thermostat is closed, the water returns to the pump via the upper of the two pipes ( return pipe) on the front of the head.

When the thermostat starts to open, the block off plate on the bottom of the thermostat begins to close off the opening to the " return" pipe and begins to direct flow into the thermostat housing and hence to the heat exchanger. After traveling thru the HE the coolant returns to the circ pump and starts its trip over again. When the thermostat is fully open no water travels out the return pipe and everything goes to the HE.

The temp of the thermostat housing should very closely follow the temp of the water flowing thru the thermostat. If the housing gets to 227 degrees, either the thermostat isn't opening, the return pipe isn't being blocked off, or water can't flow thru the HE. Use your heat gun to check the temp of the water pipe into the HE and the water pipe out of the HE. The water into the HE should be maybe 195 degrees max, and the water out of the HE should be about 20-25 degrees cooler. Did you clean all the green slime out of the HE?

DougR