Blew the waterpump hose apart on 3.0 Volvo Penta

[87baylinercapri]

Greetings, here are the details on the boat. Its a 96 four winns, with only 30 hours on it...yes...30 hours on the original engine. its a 4cyl volvo penta (omc cobra) , gm engine with sx cobra outdrive. great engine! however yesterday i pulled it out of storage, reconnected all the cooling hoses that were all removed for winterization, put the battery back in, and fired it up. drove it around for a few mins and then it blew the hose that runs from the impeller pump (belt drive) to the thermostat housing off the back of the impellar pump. so i put that back on thinking i didn't tighten the clamp enough... so i tighten it good and tight...drive it about 5 more minutes (full throttle down to idle and back) and BAM-O my large hose that runs from the side of the block up to the thermostat housing on the starboard side blew APART! there was a large tear in it roughly 4-5 inches long and obviously shooting water out. what could of caused this?!?!? i beleive the hoses are original from 96, but look to be in good shape still....im wondering if this was just a worn hose that couldn't hold pressure anymore or if some how some lines got clogged and caused a pressure build up. i already removed all water carrying lines , nothing in there, removed thermostat housing, nothing there blocking anything. also remove the impellar, it looked brand new, nothing missing from it that could of broken off and blocked flow...so im at a loss, im guessing it was just wear and tear on that hose that caused it to blow...any opinions? anything else i should check?

 

[Bt Doctur]

Re: Blew the waterpump hose apart on 3.0 Volvo Penta

when you winterize have you been putting anything in the block,manifold,riser or leaving them dry? could have a severe build up of rust/corrosion in the manifold /riser blocking off the water from exiting the motor.has the riser ever been changed?

 

[Don S]

Re: Blew the waterpump hose apart on 3.0 Volvo Penta

Your problem is EXACTLY why you don't just hook up the hoses and battery and put it in the water. You have absolutly no clue if things will work or not.
You should follow a procedure for getting your boat ready for the water, which includes running it on muffs to make sure everything is ok before you put it in the water.
So now, you need to pull it out of the water and run it on muffs. Do you have water coming out the transom shield exhaust reliefs and the prop?
Pull the block drain plugs again and see if there is water in the block, is there?
One other thing, the raw water pump on a Volvo will only put out about 10 psi pressure when perfect and at high rpm, so you will not be blowing off/up hoses even if you blocked the water exit of the pump. Those rubber impellers will not build pressure.
Are you ABSOLUTLY POSITIVE you don't have the inlet and outlet hoses on the pump reversed?

 

[87baylinercapri]

Re: Blew the waterpump hose apart on 3.0 Volvo Penta

wow, now that i've been verbally attacked i suppose i will answer your questions regardless

1) you should never assume anything, i did run it on muffs for ~10 mins to get up to temp, after which i killed it and dumped it in the water

2) the riser has been off to change the hose that connects the down pipe to the riser, i didn't notice any excessive rust/corrosion.

3) i pulled the t-stat and notice the plunger is not straight in the bore and apepars to be stuck, heated it up and it will not open, even at 245 degrees boiling water. so im left to wonder if this Beotch didn't open, stayed shut and the pressure that lasted awhile in addition to an old hose created this issue. none the less, at the end of this weekend im putting in the new hoses / t - stat, pulling the riser just to peak and put it together and run it for a long azz time , which the neighbors will love

also, is there a diagram i can reference to assure myself that the hoses are on right, most of them only fit one way anyway but it wouldn't hurt to double check things

any other suggestions? and please, if you want to belittle me for not being a journeymen marine mechanic, save it.

 

[DHPMARINE]

Re: Blew the waterpump hose apart on 3.0 Volvo Penta

journeyman,

Generaly I would ignore your post and pert reply to the people who have tried to answer your question,but sometimes I can't help myself.

I don't brag ,never will,but look at the number of posts Don S has.And I think you have 30.

And you dis his opinion.

I also think your seawater pump hoses are reversed.Tell us more because we aren't there to see it.


DHP

 

[sabastianunf]

Re: Blew the waterpump hose apart on 3.0 Volvo Penta

87-
Don't be so sensative and realize that a lot of people do not use their brains when working on thier boats. Don was not trying to attack you - just giving you good advice in a clear direct manner. He may not be the easiest going guy on this site but he definately know his way around a boat. I would take his advice and be grateful that he is not charging you $75 per hour for it.

 

[87baylinercapri]

Re: Blew the waterpump hose apart on 3.0 Volvo Penta

not even worth replying to comments posted above that have nothing to do with this topic...

i will be looking into those hoses being possibly reversed, any links to diagrams?

 

[Gary H NC]

Re: Blew the waterpump hose apart on 3.0 Volvo Penta

Service Manual!

 

[Don S]

Re: Blew the waterpump hose apart on 3.0 Volvo Penta

yesterday i pulled it out of storage, reconnected all the cooling hoses that were all removed for winterization, put the battery back in, and fired it up. drove it around for a few mins and then it blew the hose that runs from the impeller pump

Please explain to me how I should know you ran it for 10 minutes on the muffs by what you said above.

If I knew your full model number of your engine or the SN, I could probably post a picture of how the hoses should be hooked up.

 

[87baylinercapri]

Re: Blew the waterpump hose apart on 3.0 Volvo Penta

3.0 Volve penta GX with SX Cobra Outdrive , carb motor (dont know if FI was an option then or not)

 

[Don S]

Re: Blew the waterpump hose apart on 3.0 Volvo Penta

No such thing as a 3.0GX that I am aware of.
I need the letters after the GX, something like 3.0GSABCD as shown by the ABCD in the example. That's what tells me the year model of your motor.

 

[Capt Ken]

Re: Blew the waterpump hose apart on 3.0 Volvo Penta

I've actually had several 3.0 with the SX drive blow the hoses off. It due to a pugged manifold. With the system open to the air all winter, you built up some rust scale and when running, it moved and plugged up the riser.

 

[87baylinercapri]

Re: Blew the waterpump hose apart on 3.0 Volvo Penta

GS whoops not GX .

and just to make sure im on the same page, the riser is the metal elbow piece attached to the intake/exhaust manifold that goes up then angles the exhaust down to the downpipe. correct? if so is this a part that should be replaced every so often or ?

 

[Reel Poor]

Re: Blew the waterpump hose apart on 3.0 Volvo Penta

Part #15 would be the riser.

 

[Bt Doctur]

Re: Blew the waterpump hose apart on 3.0 Volvo Penta

Riser replacement is somewhere around 4-6 years depending.Had the same thing happen to me on a GM4 cyl.blew the hose between the circ pump and therm housing.riser plugged solid under way and the water had no place to go.might want to try to feel pressure on the hose that blew,if soft at idle and bludging at high idle, cooling system is restricted somewhere.

 

[87baylinercapri]

Re: Blew the waterpump hose apart on 3.0 Volvo Penta

i will also remove the riser and check also. so far thermostat looks like an issue, as stated above the plunger is in sideways and wont open in boiling water.

 

[mikeneal]

Re: Blew the waterpump hose apart on 3.0 Volvo Penta

I am betting on plugged up riser, although the t-stat not opening up in boiling H2O is issue, the cooling system has by-pass, otherwise would blow the hose prior to t-stat opening all the time.

 

[87baylinercapri]

Re: Blew the waterpump hose apart on 3.0 Volvo Penta

I am betting on plugged up riser, although the t-stat not opening up in boiling H2O is issue, the cooling system has by-pass, otherwise would blow the hose prior to t-stat opening all the time.

any specific part of the riser or is this something that would be obvious????

 

[87baylinercapri]

Re: Blew the waterpump hose apart on 3.0 Volvo Penta

I pulled the riser off, there seems to be no issue in the water passages at all, i used the hose and shot some water in and the water flows freely through the water passages all the way from where it attaches to the manifold to where it streams into the downpipe......so basically only thing fishie was the stuck thermostat, there seems to be no excessive rust anywhere in the engine.....any other ideas? im hoping i just had the hoses backwards coming off the back of the impellar pump...

btw the way the engine model number is volvo 302cpnc

any pics of how the cooling hoses should be hooked up?

thanks guys for all the help..

 

[imported_erick]

Re: Blew the waterpump hose apart on 3.0 Volvo Penta

Any resolution? I also have excessive pressure in my hoses.

Thanks