Volvo penta overheats... Hard one!!!

[mr.bobdobalina]

VOLVO PENTA 5.7 GXI 2004

I REPLACED MANIFOLDS, AND RISERS BECAUSE THEY WERE CORRODING AND RISKING THE ENGINE. BEFORE THE REPLACEMENT ENGINE WAS GETTING STEAM OUT THE EXHAUST THRU HULL, BUT RUNNING AT NORMAL TEMP.

AFTER REPLACEMENT...RISER ALARMS TRIPPING AND TEMP GOING TO 220 ON RISER, AT IDLE AT THE DOCK. AT 3000 RPM AT THE DOCK, THE TEMP BACKS OFF TO NORMAL RISER TEMPS.

HERE'S WHAT I'VE DONE SO FAR

--NEW THERMOSTAT
--NEW IMPELLAR
--THEN NEW RAW WATER PUMP
--NEW CIRC PUMP


STILL OVERHEATS AT IDLE, EVEN ON THE FRESHWATER FLUSH HOOKUP.

CHECKED HOSES BEST I CAN-- CAN'T FIND ANY LEAKS.
CLEAR HOSE DIDN'T SHOW ANY BUBBLES.
THE FLOW TEST SHOWS LESS THAN 2 InCHES OF FOUNTAIN AT IDLE--SUSPICIOUS.

DON'T KNOW WHAT TO DO NEXT. HAD A PRO AT THE BOAT HE DIDN'T FIX IT, SAID IT WAS NORMAL AND OK BECAUSE THE THERMOSTAT WASN'T OVERHEATING. BUT 220??? NOT OK BY ME, PLUS THE TWIN ENGINE RUNS AT 130 ON THE RISERS.

I'M GONNA TAKE OFF THE RISERS AND MANIFOLDS AGAIN, AND SEE WHAT I MIGHT HAVE CRIMPED OR DONE WRONG.

ANY IDEAS-- I'VE TRIED ALMOST EVERYTHING FROM ANOTHER POST THAT IS TOO LONG FOR ANYONE NEW TO DIGEST...SO I POSTED THIS ANEW.

 

[rodbolt]

Re: Volvo penta overheats... Hard one!!!

what brand manifolds and what brand/type gaskets?
did you use any sealer and if so what?

 

[tkrfxr]

Re: Volvo penta overheats... Hard one!!!

I had a similar problem, which I resolved on another thread....but one thing I tried was to take a long hose and several connectors, and rig the water inlet from the other engine to the water pump, and see if the temperature rises....if it does, it's not water inlet restriction or air ...check impeller, pump, heat exchanger, hoses to manifolds, etc...

I also tried it with the thru-the hull water pickup from the genny...it worked....I eventually found my air leak...

you can also rig the good engine to draw water from the overheating one's water pump inlet hose....if it overheats, it is water inlet restriction, or air entering the system....

keep at it.

-good luck!

 

[Black as]

Re: Volvo penta overheats... Hard one!!!

Sounds like a gasket leak.

 

[tkrfxr]

Re: Volvo penta overheats... Hard one!!!

Sounds like a gasket leak.

Which gasket?

here is a cooling diagram for closed cooled version of his engine...

 

[Black as]

Re: Volvo penta overheats... Hard one!!!

Which gasket?

here is a cooling diagram for closed cooled version of his engine...

Manifold gasket's.

 

[tkrfxr]

Re: Volvo penta overheats... Hard one!!!

Manifold gasket's.

Ah!....wouldn't he have water in the cylinders?

(maybe he should check)

 

[Black as]

Re: Volvo penta overheats... Hard one!!!

Not necessarily, it could be from the exhaust port and the pressure is higher than whats in the manifold, therefore exhaust gases are entering your water jacket in the manifold and heating it up and also depends on the quality of your manifold as well.

Did you use a sealant when you fitted your manifolds and tensioned the bolts equally.

 

[mr.bobdobalina]

Re: Volvo penta overheats... Hard one!!!

i love the idea of a long hose to check the drive inlets! thanks tkr fxr.
i'm pretty sure that isn't the problem because the flow to the manifolds from the tstat housing is just the same as it is on the good engine. But it's hard to quantify, perhaps it's reduced.


IF the manifold were leaking how would that cause the riser to overheat. The exhaust from the engine would be leaking into the bilge instead of flowing out the manifold and riser. The water jacket is sealed off from the gas flow passages, so even if there were leaking exhaust gas... the water jacket would still be getting the same flow of water from the hoses coming from tstat housing. This if anything should cause the risers to be cooler because they have the same water flow and less hot gas. That's what I would think? Am I wrong.

wit's end possibilities.
--risers and manifolds are aftermarket and their flow isn't as good as volvos.
(seems ridiculous, but could be. and the volvo tech said this is possible)
--something in the exhaust pipes is backing up the flow of exhaust and making the risers hot.
--I didn't prime the manifolds with water before starting the engine.
(wouldn't they fill pretty fast? Doesnt' seem like this would explain poor cooling over a long period of time)
--the engine runs hot explore mechanical reasons for this.


gonna hook up the water inlet from the good engine now. thanks tkr fxr!!!!

 

[mr.bobdobalina]

Re: Volvo penta overheats... Hard one!!!

Seawater line from other engine didn't do too much. One side risers stayed cooler maxing out at around 155. Which is livable but higher than it used to be. And there is no load on the engine so I imagine this will be higher while underway.

The other riser though still went to 250 degrees. Engine temp stayed below 175 the whole time.

so now we know it's not the impellar, thermostat, raw water pump, circ pump, air leaks on the water side of the cooling system, hoses have been checked and replaced.

Whats left.

risers and manifolds aftermarket construction.
risers and manifolds installation, leak, plugs not sealed thouroughly, etc.
Engine runs too hot at low rpm...but why wouldn't it overheat?


I can't see how a cast iron chunk of metal can be defective in anyway (if it doesn't leak, it fits tight) don't they pretty much copy the flow path as the volvo riser. it looks exactly the same on the outside.

 

[tkrfxr]

Re: Volvo penta overheats... Hard one!!!

I assume your engines are raw water cooled.

Do you have a flushing adaptor in the cooling system? like this one:

http://www.marinepartsexpress.com/engine_flush.html

Does the engine overheat with the garden hose, at idle, at the dock?

You said the engines are 5.7 Gxi 2004 (which model?)... but what exactly made you replace the manifolds and risers? My engines are about the same age, and my risers bled some rust, forcing me to look inside, only to find the were in good shape...I did clean them and put them back...

http://forums.iboats.com/showthread.php?t=381272

Did you get Volvo replacements? or other brands?

 

[Don S]

Re: Volvo penta overheats... Hard one!!!

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

 

[mr.bobdobalina]

Re: Volvo penta overheats... Hard one!!!

I assume your engines are raw water cooled.

Do you have a flushing adaptor in the cooling system? like this one:

http://www.marinepartsexpress.com/engine_flush.html

Does the engine overheat with the garden hose, at idle, at the dock?

You said the engines are 5.7 Gxi 2004 (which model?)... but what exactly made you replace the manifolds and risers? My engines are about the same age, and my risers bled some rust, forcing me to look inside, only to find the were in good shape...I did clean them and put them back...

http://forums.iboats.com/showthread.php?t=381272

Did you get Volvo replacements? or other brands?

it overheats at idle with garden hose attached. It overheated with the seawater incoming line from the twin engine that runs at normal temp (i took your idea).
they are hge risers and manifolds. they look exactly the same. i changed them because South Florida eats them alive and mine were leaking on the outside. The old risers were eaten away pretty bad. Wasn't worth risking the engine.

but it runs cool as a cucumber at 3000 rpms. So it's not getting the flow of water needed at idle. I don't know why not...

why does the other engine run normal? Maybe the risers and manifolds are so rusted they have extra cavity space in the water jacket? Who knows. I'm so perplexed now its crazy.

the incoming line from both engines causes overheat even though it's good on the other engine.

maybe the lean running engine is too hot at idle for the cooling system to cool, but at higher rpms it's not so lean, and better flow?

gonna call my volvo mechanic and have him work on it some more.

 

[mr.bobdobalina]

Re: Volvo penta overheats... Hard one!!!

halleluia!!!!! problem solved.

The HGE Risers and Manifolds are JUNK!!!!!!! NEVER USE THEM IN PLACE OF VOLVO. IN FACT, NEVER USE THEM PERIOD!!!!!

should have done this way earlier. But swapped the port engine risers in, and presto... runs at 120. warm to the touch. no heat!

I can't believe it. These things are engineered junk. The flow pattern in the water jacket is crap. The casting metal is junk. I mean who knows when the manifold would crack and ruin an engine. JUNK JUNK JUNK!

Failing right out of the box. I should have figured it out sooner. But I spend 60 hours in that bilge. 800 bucks on parts and pumps for the entire cooling system. Now I have to return them to the store. Let's see if they give me my money back! I would hope so, to say nothing of the aggrevation etc.

Well lesson learned. Mans and Risers are probably not a good place to use aftermarket parts on the vp 5.7 gxi

--the end.