Oil cap pops off on 5.7l penta Volvo gsi

[Jhilton0816]

I have a 2001 Larson 234 escape deck boat with a 280 hp Volvo penta 5.7 gsi motor, I was on the lake after fixing my power steering pump issue dealing with the hose coming disconnected, and i start hearing this clacking noise, and I stop to see my engine bay full of smoke, apparently the oil cap popped off and melted away, I figured whoever did the oil last must not of tightened it all the way, so I didn't know how to get an oe oil cap so I bought one that I thought looked similar at a parts store, well it seems to pop off when I exceed 25-30 mph. Someone told me it could be the crank case building pressure, and I asked why and they said it could be clogged filters or something idk, I have no clue where these filters are or why it's coming off, and I noticed the other day a hose is disconnected that has a joint hose fitting melted I think I may know where it goes and I wonder if this is what's causing the oil cap to come off as I think it goes into the gasket covers to relieve pressure once again I don't know but I will post links to pictures, any help is very appreciated....

 

[Jhilton0816]

http://imgur.com/uFe7ioo http://imgur.com/Zb3u8A9 http://imgur.com/HKQzGOZ

 

[alldodge]

I have a 2001 Larson 234 escape deck boat with a 280 hp Volvo penta 5.7 gsi motor, I was on the lake after fixing my power steering pump issue dealing with the hose coming disconnected, and i start hearing this clacking noise, and I stop to see my engine bay full of smoke, apparently the oil cap popped off and melted away, I figured whoever did the oil last must not of tightened it all the way, so I didn't know how to get an oe oil cap so I bought one that I thought looked similar at a parts store, well it seems to pop off when I exceed 25-30 mph. Someone told me it could be the crank case building pressure, and I asked why and they said it could be clogged filters or something idk, I have no clue where these filters are or why it's coming off, and I noticed the other day a hose is disconnected that has a joint hose fitting melted I think I may know where it goes and I wonder if this is what's causing the oil cap to come off as I think it goes into the gasket covers to relieve pressure once again I don't know but I will post links to pictures, any help is very appreciated....

Are you saying your power steering pump oil cap is what keeps coming off?

The item in the pic is a plastic end piece which in most cases is attach next to the flame arrestor so oil fumes are pulled into the motor when running.

 

[Jhilton0816]

No the oil cap which is now the yellow thing in the picture whij is also about to be replaced because it blew off and melted as well, and that hose I heard with the joint elbow plastic thing is the crank case vent hose and it goes in the hole in he back in the picture

 

[alldodge]

No the oil cap which is now the yellow thing in the picture whij is also about to be replaced because it blew off and melted as well, and that hose I heard with the joint elbow plastic thing is the crank case vent hose and it goes in the hole in he back in the picture

Starting to sound like the motor is overheating with things melting. The blowing off part is caused by to much blow-by around the rings, or a cracked piston. How is it running, does anything smell hot? Any other symptoms?

 

[Bondo]

Ayuh,.... Agreed,..... It shouldn't be hot enough to melt things, in those areas,.....

Something is Wrong,....

Probably oughta start with changin' the Impeller,.....

 

[Jhilton0816]

http://imgur.com/9GKaohq
I just bought a new elbow joint and oil cap, and I put the elbow joint in the hole on the back as well as connected the hose to it, I don't know what's causing the oil cap to blow off, but a buddy of mine insists that tube and hole is the crank case vent hole and that with the tube reconnected and the joint back in the hole it should bent so the pressure won't blow the oil cap off, other then thAt the stuff only melted when it was blown off and was just laying on top of the engine, engine seems to run fine, it has no issues or hiccups when going, the temp gauge doesn't exceed about 130-170 Fahrenheit I believe, but I figured the stuff melting is normal considering you truck engine is extremely hot to the touch after you just been driving it all day........ Would make sense things melt at like 170 degrees right?

 

[Jhilton0816]

http://imgur.com/xgrS1IN And here is the picture of the propeller or impeller idk what it's called on boats, but I guess it could use a change? It's knicked up and whatnot, but like I said the only other problems I've had with this boat was a power steering hose issue(fixed with better clamp) and he trim not going down(fixed suposably cause it's ran off power steering fluid because it worked after I got more fluid in there)
And then there is the on going problem of something draining the battery so I have to disconnect the battery every time I'm done with the boat

 

[Bondo]

http://imgur.com/xgrS1IN And here is the picture of the propeller or impeller idk what it's called on boats, but I guess it could use a change? It's knicked up and whatnot, but like I said the only other problems I've had with this boat was a power steering hose issue(fixed with better clamp) and he trim not going down(fixed suposably cause it's ran off power steering fluid because it worked after I got more fluid in there)
And then there is the on going problem of something draining the battery so I have to disconnect the battery every time I'm done with the boat

Ayuh,.... That's the Propeller,....

The Impeller We're talkin' 'bout is a piece of rubber inside the raw water pump, that pumps coolin' water from the lake into the motor,......

My guess, bein' a Volvo, it's mounted to the front of yer motor, 'n either belt driven, or crankshaft driven,.....

It's a wear-out part that needs changin' every couple of years,...
Part of the Maintenance thing,....

 

[Jhilton0816]

http://imgur.com/aKlSSU9
I don't think I see where it would be on the front but I watched a video of an outboard and it looks like it could possibly be on the bottom part of the stern drive

 

[Bondo]

http://imgur.com/aKlSSU9
I don't think I see where it would be on the front but I watched a video of an outboard and it looks like it could possibly be on the bottom part of the stern drive

Ayuh,.... It's crankshaft mounted,... Almost outa sight at the bottom of yer picture,...

 

[dannys2004glastron175mx]

number 2 http://www.marinepartseurope.com/en/volvo-penta-explodedview-7797410-26-10804.aspx

 

[Jhilton0816]

Ahh I see, I suppose I should change that because idk if the previous owner has, still wish I knew what causes that oil cap to pop off when I get past a certain speed, Ima itchin to take the boat out either today or sometime soon to see if me re connecting the hose into the new elbow joint would fix the problem

 

[alldodge]

Ahh I see, I suppose I should change that because idk if the previous owner has, still wish I knew what causes that oil cap to pop off when I get past a certain speed, Ima itchin to take the boat out either today or sometime soon to see if me re connecting the hose into the new elbow joint would fix the problem

The blow off is one of the two things previously mentioned. Now if your engine was overheating this could have made it worse

 

[Bondo]

Ayuh,.... I'd rebuild the raw water pump,.... Before any testin',....

 

[Jhilton0816]

Well I hope it's not a cracked piston cause then I better sell the boat while it runs.... But I mean it runs fine and doesn't smell hot, neither does it get to hot, when I was at full power for like 14 mins before this event started happening the highest temp was like 150, it gets up and goes and starts with no problems... And if it's blow-by or w/e how would I go about fixing that,

 

[alldodge]

Well I hope it's not a cracked piston cause then I better sell the boat while it runs.... But I mean it runs fine and doesn't smell hot, neither does it get to hot, when I was at full power for like 14 mins before this event started happening the highest temp was like 150, it gets up and goes and starts with no problems... And if it's blow-by or w/e how would I go about fixing that,

Depends on how bad it is, and I would say since yours is blow oil caps off it does show signs its in bad shape. Run a compression test to see what your numbers are and it its one or more cylinders. If its bad enough you can try water to steam away the carbon (make sure its done right), otherwise would need to rebuild/replace the engine.

 

[Redeye1620]

Check your pcv valve. It should be mounted on one of the valve covers & have a vacuum line going to the intake manifold. Pull the pcv valve from the valve cover & shake it. It should rattle. If not it is bad. Also follow the vacuum line & make sure it is not broken & attached tightly to the intake....-Rich

 

[Jhilton0816]

So apparently buddy says my engine is overheating, and I talked to a guy who had a similar issue and he said that I need to rebuild my water pump by changing out the impeller and then checking the hoses to make sure impeller parts aren't at he ends.... He said once I do that my boat should run fine.... I haven't done a compression test yet but he said if it was a head gasket or issue like that... Then I shouldn't be able to run the engine for 30mins without issue... That I would notice smoke after like 5 to 10 minutes.... Also note as one of the big water hoses was leaking water at the end as the engine start overheatong.... Buddy says that's still cause your impeller is probably shot.... So tomorrow morning I'll be taking off my water pump or w/e and check the impeller.... Also can anyone tell me where do I disconnect the ignition so I can do a compressor check tomorrow as well

 

[jerryjerry05]

To do a comp test:
Remove all of the plugs.
Mark the wires if needed.
Then at the starter solenoid hook a jumper or start box.
No jumper? Pull the coil wire(not recommended)
Install the comp tester.
Then with the jump box turn the motor over.
Then as the motor turns over the gauge will stop after a few revs.
Write the reading down.
Repeat on all cylinders.

If the battery dies?
The radio might e killing it?