Volvo Penta 2003 (non-turbo), Overheating?

[Paul L]

NOTE: If engine is revved over 2200rpm suddenly temp of tstat housing starts rising from 180 to 200+. Temp goes down when throttle is reduced.

What are the test conditions? Is this under load or in neutral?

[Capt Ben]

Under load.


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[deblen]

Originally Posted by Capt Ben

Still having overheating issues....
Has anyone suggestions for how to best flush engine coolant in block? I've done the prestone flush twice and am back to this as a possible solution.

-
Great seawater output now that I've cleaned the heat riser elbow.

-Acid bath cleaned heat exchanger. She's clean now.

-Thermostat checked.

-Circulator coolant pump opened up and it looks perfect.

-Hot water system works (sink and shower), coolant moves through hot water tank.


NOTE: If engine is revved over 2200rpm suddenly temp of tstat housing starts rising from 180 to 200+. Temp goes down when throttle is reduced.

BTW, should coolant nearly continually be entering the reservoir from tstat small hose? Might this occur if coolant doesn't move through block freely? I'll try blowing through system again.

Need to find the magic bullet that solves this issue asap. Thanks to all the great suggestions previously received.


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If coolant is "continually...entering the reservoir from tstat small hose",I suspect that may be your problem. Enough coolant is bypassing the engine thru this 1/4" hose to reduce cooling at hi RPM ?
There should not be any coolant circulating via that route.
Figure out why/how coolant is getting to this route. There are 2 t-stats for the 2000 series eng.-one for raw water cooled & one for fresh water cooled.Recently there was a post on here or on YBW forum explaining how the t-stat works on the two different cooling systems.

Hope this helps / Len

[DeepFrz]

I haven't gone back through the thread but have you rebuilt or replaced your water (coolant) pump?

[Rustic Charm]

Originally Posted by deblen

Coolant does not move continuously from T-stat housing thru small 1/4" hose to plastic reservoir on my 2003.In fact,I have never noticed it moving thru the small hose at all,but I assume it occasionally does when coolant is extra hot & needs a place to "expand" to.Not sure how this part-the 1/4" hose-works.
Hope someone can explain it.
/ Len

It's actually just for releasing pressure. and along with the release of pressure comes some coolent.

[Paul L]

Originally Posted by Capt Ben

Under load.


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Will the engine reach its max RPM under load? I'm wondering if the prop is not matched or the running gear is not clean or if the bottom is fouled.

[Capt Ben]

UPDATE: After removing and going through the Circulator pump, I am now confident that it was and is working correctly. Everything is put back together now and I've run some more tests. I've run the engine in gear, under load, at the dock at a few different rpms:

At 1800 RPM, in gear, temp on Stat housing is around 145F.
At 2200 RPM, in gear, temp on Stat housing is around 165F.
At 2800 RPM, in gear, temp on Stat housing is around 172F.
At 3000 RPM, in gear, temp on Stat housing is around 178F.

At all of these readings temperatures were essentially stable. At the highest RPM, the Heat Exchanger started getting warm to the touch ± 90F (sea water is about 57F). Hot water was generated from the outputs to my water system (those hoses hovered around 140F).

So, it seems that the overheating issue is resolved. It is my belief that the culprit was two fold. The Heat Exchanger was a bit clogged prior to muriatic acid baths and is now very clean. The Heat Riser was very obstructed with rust and only allowed a little bit of water flow output. Now that I've cleaned that out, water output is far greater than when I bought the boat 15 years ago. It's actually pretty impressive now. I think these two issues were the culprit and that getting all air out of the system was difficult and led me to not having the issue solved previous to tearing apart the circ pump.

So, I have now noticed that I have a problem which is related. Coolant is very slowly pooling at the indent where each injector enters the cylinder head. About 10 years ago, I replaced the injectors and the copper sleeves that they fit into. Could the copper sleeves be the problem? Maybe I should try re-torquing (14.7 ft pounds) the injector hold down bolts. Any suggestions or thoughts from this amazing group of knowledgable folks?

[Capt Ben]

Originally Posted by Rustic Charm

It's actually just for releasing pressure. and along with the release of pressure comes some coolent.

YES, just for giggles, I pinched closed that hose and the reservoir still was showing a lot of action. I think that is a slight back feed of the pump generating bubbles, back through the reservoir line which joins with the HE output as it runs to the pump. So, I was not getting coolant output through that hose, possibly some air.

[Rustic Charm]

Originally Posted by Capt Ben

UPDATE:
So, I have now noticed that I have a problem which is related. Coolant is very slowly pooling at the indent where each injector enters the cylinder head. About 10 years ago, I replaced the injectors and the copper sleeves that they fit into. Could the copper sleeves be the problem? Maybe I should try re-torquing (14.7 ft pounds) the injector hold down bolts. Any suggestions or thoughts from this amazing group of knowledgable folks?

Capt, are you reporting that there's coolant pooling around the injector sleeves?

Because, I would not have thought that likely. And there's barely any pressure on holding them down, the hold down bolts I thought just stopped them from flying out. Where did you get the 14.7 pounds from?

[Capt Ben]

Yes, coolant seems to be coming up and appearing at the top of the injectors. I got the 14.7 foot pounds from the workshop manual as the torque setting for the injector bolts.


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[deblen]

Congrats Capt Ben on the cooling cure.
Haven't had any coolant leaks around injectors yet,so I will let more experienced folks reply on that.
I will just suggest you make sure it is a leak & not just some wetness lying in there from working on system. Good luck! / Len

[Rustic Charm]

Originally Posted by Capt Ben

Yes, coolant seems to be coming up and appearing at the top of the injectors. I got the 14.7 foot pounds from the workshop manual as the torque setting for the injector bolts.


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Yep your right 14.7 pounds for mine too. It's not much, I'm just hadn't realised it.

If you have coolest coming up through there my suspicion is you have a serious problem. I can't see how clamping them down more will make any difference. Is it leaking with all three?

[Capt Ben]

Thank you Deblen.

Unfortunately, I've carefully observed the coolant reform as I daub away with a paper towel a constant dribble from each injector cylinder head well.

I think I need to replace the copper sleeves that seal and provide a coolant wall. I guess I'll make this s winter boat yard project.
At least I can do my Chicago Lock and 24 bridges river trip to my winter storage boat yard in a couple of weeks. All boats must be out of the Chgo harbors by 10/31.


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[Capt Ben]

Rustic Charm, yes it's coming out of all three.

I believe that when I had a pretty serious initial overheating that the cylinder head expanded and loosened up some how or popped somewhat the copper sleeves that are pressed into the head to hold the injectors and provide a coolant wall.

I'm considering just replacing the sleeves. Unfortunately, I'll have to see if I can again borrow the special Volvo tools for removal and pressing in.

To me, a big question is, do I purchase the carbonizer gasket kit and remove the head & have the valves reset, and replace the sleeves? Or do I just do the sleeves?


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[Paul L]

Don't you have to remove the head to replace the sleeves? I did, when I replaced mine. Once you remove the head you might as well have the valves done and you will need the new gaskets from kit. Oh, and the injectors are coming out, so they may as well be tested too. Its a slippery slope.