5.0GL-D - Overheats after 4th run on new impeller - Pics Attached

[83Evinrude]

Prior to our last lake trip I ordered a new impeller, it was advertised as new OEM Genuine Volvo part# 21951348 and replacing 3862567 and 21213660
Upon arrival it appeared fine so I installed it and tested on muffs, and after the engine filled up water came out around the transom as expected.

Last week at the lake I ran the boat three times, mostly at low planing speeds under 3000rpm and the temp ran 160-170 each time.
On the fourth time out as we headed back to the ramp I opened it up a bit, probably reaching about 4000rpm and after a few minutes the hot horn sounded and the temp was around 200.
I stopped the engine, trimmed up the out-drive and checked for debris on the intake but found none and a engine bay check found no obvious problems either. You could touch the manifolds but they were clearly hot, and you could feel water bubbling inside.

Waited a few minutes, then restarted to see if lower speeds would provide enough water flow to cool the engine but this didn't happen.
A friend towed us back,and by the time I backed the trailer down the ramp running it a couple of minutes to load on the trailer did not produce an overheat.
At home, I didn't hook it up to muffs but took the pump apart to see what shape the impeller was in.

I've linked to pictures of the pump, impeller, thermostat housing and intake manifold where it bolts to.
The pump has a groove in the back of it but I'm not sure if this is a problem or not.
The impeller appears fine to me, and after taking it out the vanes returned to just about straight after a few minutes.
I took the thermostat housing off to see if it had stuck closed but I can't see how to get it out of the housing, and every automotive application I've seen would have had the thermostat in a groove in the intake manifold and held down by the housing. Water will run through any of the housings hose connections to the others so I'm not sure how it functions where its located.

Sticker on the motor has these markings: 5.0GL-D, 3869216 and 4012100510

Thanks in advance for all advice.


http://s85.photobucket.com/user/ston...Pump.jpg.html]

http://s85.photobucket.com/user/stonypass/media/VolvoPump/Impeller_1.jpg.html]

http://s85.photobucket.com/user/stonypass/media/VolvoPump/Impeller_2.jpg.html]

http://s85.photobucket.com/user/stonypass/media/VolvoPump/Housing.jpg.html]

http://s85.photobucket.com/user/stonypass/media/VolvoPump/Manifold.jpg.html]

 

[bruceb58]

Your pictures didn't come through. Use Photobucket and use the img and /img commands. That's the only sure way to post pictures right now as it works every time.
.
The thermostat is held in with an o-ring.

Unfortunately, DonS passed away a year ago.

 

[83Evinrude]

Bruce:

Very sorry to hear about Don, my belated condolences to his family and friends.
I've added links to the pics, thanks for any help you can provide.

So to get the thermostat out, I'd just pull with a pair of pliers?
There is an o-ring behind it holding it in?

What do you think of the pump housings condition?
Its a 2004 boat, I purchased it in 2009 and replaced the original impeller then.
I think this is the third one I've installed, and they've all looked good to me when removed.

I was surprised that restarting the engine at idle didn't circulate enough water to immediately lower the engines temperature.

 

[bruceb58]

You can see the o-ring in the picture. Use a screw driver or a pick to remove it.

The housing looks ok but kinda hard to tell from a picture.

 

[Maclin]

Just spitballin' a little....

I am thinking that even with a stuck thermostat there is enough water bypassed to the exhaust to keep them at a more normal temp to the touch, but maybe heatsoak from the block could affect that. Those being too hot to touch to me means raw water flow is not good ahead of that.

I am remembering posts about some raw water pumps in that vintage having some problems with leaking at the inlet or outlet tube. Leaking at the inlet would suck in air and lose water flow that way, water would not be solid but bubbly which is not good for cooling. If the outlet leaked then you know because water drips or runs out. On the inlet it would be less evident until an overheat.

If there is a problem of sucking air between the outdrive internal plumbing and the pump then just idling with the outdrive mostly underwater should have covered up those leaks so to speak and the temp go down some at least.

There could possibly be a problem with the hose inside the boat coming from the transom, any leaks there would have the same issue of losing suction.

The impeller looks very good so it must be seeing enough water to keep it from failing, kind of fits in with the bubbly water scenario.

 

[83Evinrude]

Probably want to replace the thermostat since I have it apart, is an automotive thermostat and gasket alright to use?
I'm assuming a 160 degree version, is that correct?

The hose from the out-drive to the transom looks fine and all the others in the engine compartment do as well.
Circulation pump bearing feels fine and the belts to it are only a couple of years old and adjusted properly.

Not sure I understand how to tell if the raw water pump is doing its job correctly, other than to see good water flow around the transom when on muffs.
I could post a video later when its back together for someone to confirm for me.

 

[Maclin]

I like to get the thermostat kit from VolvoPenta. The materials and temp range are correct for the raw water environment. They come with new oring, they can be for a range of applications so there are usually different gaskets, also an instruction sheet or at least a "Don't do this" sheet.

 

[skydiveD30571]

There's an instructional link up in the stickies for diagnosing cooling issues with a VP engine. A good way to test raw water pump function is to insert a section of clear hose in between the pump and thermostat housing so you can see the quality of suction the pump is producing. If there are bubbles, you can try inserting another piece of clear hose just before the pump inlet. If you have good solid water flow there you know it is a pump problem, and if you still see bubbles you know the problem is somewhere between there and the water inlet on the drive.

 

[bruceb58]

The thermostat is not an automotive one. It is a different design since it sits up in that housing.

 

[dypcdiver]

Something that has cropped up on here previously is that, because it is difficult to see the "O" ring in it's groove on the part of the pump that remains on the engine, some have not removed it and added one causing the impeller not to seal against the faces due to the extra clearance. They have also had similar problems to yours. Worth checking.

 

[jbird1214]

Folks.........I have been fighting the exact same thing with my 2004. 5.0 GL-D
And Only at High RPM's
All speeds below 25-28 mph NO Issues temp running 165
This is what I have done:
Replaced the impeller, shaft seal and oring - no leaks........tested gets hot on high rpms
Changed thermostat and oring........tested gets hot on high rpms
Started disconnecting one sensor at a time. Left exhaust ........tested gets hot on high rpms
Right exhaust........tested gets hot on high rpms
Thermostat housing sensor........tested gets hot on high rpms
Put the lower unit partially in the water; started it, ran it at idle and had suction on both sides of the outdrive
Exhaust water coming out was warm. Did not do this very long and the temp gauge showed normal temp.

Unfortunately I have no way to get this boat off the lake and trying to find someone in the area has been a nightmare.

 

[Maclin]

Jbird, might be best to start your own thread, but I have some comments. There are components/plumbing between the grates and up thru the drive then on into the boat that the water has to get sucked thru. There can be air leaks there that will not show up until on plane and most of the drive is out of the water.

 

[DCinVA]

You may have some bits of an old impeller blocking the system somewhere. If it is fresh water cooled, check the intake side of the heat exchanger for blockage.

 

[83Evinrude]

Received a Volvo Thermostat, O-Ring and Gasket from the iboats store and finally had time to put everything back together.

1. Cleaned up the thermostat housing where the hoses connect, and along with the inside where the o-ring goes with a dremel rotary brush.
2. I did check and there was only one o-ring in the raw water pump from when the impeller was replaced last month, re-installed that impeller since it looked fine after the overheat using dish soap for lube.
3. Replaced the gasket in the hose for flushing (blue cap) as the old one was very hard.
4. Tightened all hose clamp connections tightly, but there are crimp on one's to the flush hose and power steering cooler I left alone.
5. Hose to the outdrive looks fine.

Ran it on muffs for about 20 minutes and the temp gauge never went above 160.
The manifolds and back side of the thermostat housing where the manifolds water comes from stayed cool.
Front side of the housing (water to the block) got very warm but not burning hot.
Hope to get it to the lake for a test at speed in the next few days.

Below is a link showing the amount of water coming out of the lower transom at idle, does this look like enough?

https://www.youtube.com/watch?v=9iHbBZBK4fc&feature=em-upload_owner#action=share


Thanks

 

[Fleetwin]

I see you running that on a single feed muff set up. I went to a dual feed muff as mine would overheat with the single.

If you're working on the single feed, all must be well.

Did you look for debris in the heat exchanger?

 

[83Evinrude]

Mine is seawater cooled so there is no heat exchanger.

 

[dypcdiver]

Looks good to me, fingers crossed. Oh BTW don't forget to put the bung in.

 

[jbird1214]

Like I stated before, I have had the exact same issue. After trying different things exactly like 83Evinrude has done I finally got down to the bottom of mine.
It was the temperature sensor on the intake manifold. It is located under the hoses where the thermostat housing mounts to the intake. Suggest you look at replacing it with the following part number; 3852029. Volvo sells two different ones but the other one is for a dual station setup.

 

[83Evinrude]

Unfortunately after running the boat in the lake with the new thermostat, I still had temps reaching 200 degrees.
I believe its finally fixed however, details below:

On the next trip out I removed the thermostat completely, and the engine never showed above 135 degrees, but of course also never reached operating temperature.
This seemed to indicate my raw water and circulating pumps were fine along with all sensors.

I talked to a boat repair shop that suggested I drill out the passages slightly on the thermostat housing, where the hoses connect to the manifolds and where the hose goes to the raw water pump. The idea being, that over time corrosion closes the openings slightly, makes them rougher and this reduces flow.
They also recommended drilling a small hole in the flange on the thermostat, this is supposed to allow passage of any air out of the block.

I used the first drill size I had, that would remove any material from the inside of each of the three smaller hose connections on the thermostat housing.
Also drilled two 1/8" holes in the flange on the thermostat, as close to the inside diameter as possible.

Just returned from spending three days boating over the Labor Day holiday, and now the boat warms up to 160 degrees and while cruising stays there.
If I run it hard it also stays at 160, pulling it back to idle the engine goes up to 175 for a couple of minutes then again returns to 160.

Seems like this is finally fixed, and I appreciate all the responses to my issue.
Sorry for my slow responses, my work and personal life have made it difficult to spend continuous time on this problem.