VIDEO! 1996 Volvo 3.0 GS - Cooling Hose Throbbing and Bursting

[4winnsskipper]

Ok motor only has 190 hours on it, original from '96. Boat winterized most of it's life, bought it with 22 hours on it. It sure seems the original owner ran it without a water supply or in water and busted up the sea water impellar because when it first burst a hose i found the line that runs up from the sea water pump on the engine accesory drive directly to the riser (t's off) was plugged with a piece of impellar. Removed that and 30 hours later the hose burst again. I removed the hose again and found nothing. So i removed the riser and checked inside and saw no clogs, then ran water through each port of the riser and it flowed easily. So i put it back on and it's been good the last 80 hours, but the other day i had it on the muffs and was checking everything out and noticed the hose throbs when i go above like 2,000 RPMS... WTF...i usually never exceed 4,000 RPMS because of this, even though the motor still has another ~800 rpm in it according to the user manual i have and follow. So where else can i look for a clog???? is this normal?!?!? Motor runs fine and cool, stays right around the 160 ish mark as it should. I've put two thermostats in it (since i had it apart both times to look for the clog) and always use genuine volvo parts and follow the summerization, winterazation per the manual and here.

This is driving me crazy, where can i look??? I want to not worry about this anymore, i do carry TWO spare hoses just in case though... GRRRR


http://www.youtube.com/watch?v=EkFzyL1orzg


Thanks Guys!

 

[Bt Doctur]

Re: VIDEO! 1996 Volvo 3.0 GS - Cooling Hose Throbbing and Bursting

Not enough water getting out of the engine fast enough, clogged manifold and/or riser, or therm housing.
By the way, it`s not healthy to run much above idle speed on a hose.

 

[4winnsskipper]

Re: VIDEO! 1996 Volvo 3.0 GS - Cooling Hose Throbbing and Bursting

Not enough water getting out of the engine fast enough, clogged manifold and/or riser, or therm housing.
By the way, it`s not healthy to run much above idle speed on a hose.

Thanks for the tip

I never run it like that on a hose, just for video purposes.

As far as your suggestions, i had the riser off and found no clogs, i had the thermostat housing apart, found nothing clogged either.

I found it interesting there is a restrictor plate on this motor between the manifold and the riser, and it's their per volvo penta, see item 75 in the pic

 

[Blk-n-Blu]

Re: VIDEO! 1996 Volvo 3.0 GS - Cooling Hose Throbbing and Bursting

Engine circulator pump.

 

[4winnsskipper]

Re: VIDEO! 1996 Volvo 3.0 GS - Cooling Hose Throbbing and Bursting

Engine circulator pump.

??? I dont follow how that would cuase this? I had the pump off, spun fine and looked to be in good shape... Im not saying your wrong im just trying to see how that would cause this.

 

[79Glastron]

Re: VIDEO! 1996 Volvo 3.0 GS - Cooling Hose Throbbing and Bursting

Does it do that on the water? Is your home water pressure too high?

 

[JustJason]

Re: VIDEO! 1996 Volvo 3.0 GS - Cooling Hose Throbbing and Bursting

So a 14 year old heater hose blew on you... it happens... it's 14 years old. It's normal to feel circurlation, which could be described as pulsing, in hoses. I wouldn't pay it much thought unless it's overheating or pops another hose.

 

[JustJason]

Re: VIDEO! 1996 Volvo 3.0 GS - Cooling Hose Throbbing and Bursting

Just watched your video... if your racing your engine that much on the muffs your going to toast your impeller.

 

[rodbolt]

Re: VIDEO! 1996 Volvo 3.0 GS - Cooling Hose Throbbing and Bursting

check with your local volvo dealer on the tech bulliten on installing the restrictor plate.
seems the stamping on the plate,the service manual and the instructions on the gasket kit are a bit different so there is a tech bulliten now.

 

[EddiePetty]

Re: VIDEO! 1996 Volvo 3.0 GS - Cooling Hose Throbbing and Bursting

...just my humble opinion but I believe that 'throbbing' of the hose is due to air in the cooling water caused by cavitation of the impeller pump at too high an engine speed on muffs.

Do you encounter this 'throbbing' waterborne?? Bet not.

BTW....if you've been over-reving the engine on muffs very often (like just the length of the video), might as well plan on replacing the entire pump assembly.

 

[Tail_Gunner]

Re: VIDEO! 1996 Volvo 3.0 GS - Cooling Hose Throbbing and Bursting

Take your thermostat out of the motor and see if you can duplicate that....

 

[4winnsskipper]

Re: VIDEO! 1996 Volvo 3.0 GS - Cooling Hose Throbbing and Bursting

...just my humble opinion but I believe that 'throbbing' of the hose is due to air in the cooling water caused by cavitation of the impeller pump at too high an engine speed on muffs.

Do you encounter this 'throbbing' waterborne?? Bet not.

BTW....if you've been over-reving the engine on muffs very often (like just the length of the video), might as well plan on replacing the entire pump assembly.

no i dont do that often, or ever before. Please no assumptions here

What happens on the water is the hose just inflates like a ballon to slightly larger than the max inflation you see in the videeo and just stays there....

what im trying to solve is why the heck this thing inflates like that with a clear riser, clear hoses, clear thermostat housing

Please help!

 

[4winnsskipper]

Re: VIDEO! 1996 Volvo 3.0 GS - Cooling Hose Throbbing and Bursting

again while boat is in water, the hose just inflates and doesn't throb like it did when i had it on the muffs.

Any other thoughts? Thanks guys

 

[Tail_Gunner]

Re: VIDEO! 1996 Volvo 3.0 GS - Cooling Hose Throbbing and Bursting

Skipper that a pretty violent occurence going on there...I do not know of any pump in a motor that can create that kind of surge...But a thermostat can stick for whatever reason...The water boils in the block...the thermo opens and poof you get that kind of action...Take it out im sure it will go away..its the only gate in the system...Air pockets can create such a thing...Umm and those hoses are probably old and weak making it look worse..than it is...Boil some water some time under pressure and release it...And wear safety equipment...

 

[4winnsskipper]

Re: VIDEO! 1996 Volvo 3.0 GS - Cooling Hose Throbbing and Bursting

UPDATE!!! I've been running the boat just fine for awhile now, but when boat is in the water, the hose still INFLATES but doesn't pulsate like it did in the video when it was on muffs, which is because the hose couldn't supply water fast enough. Lesson learned there...

HOWERVER the hose still inflates like it does in the video and just stays!! I even had to tighten the hose more because it was working it's way off!! Higher the RPMS, the more it inflates. Motor does run warmer when cruising around (3k-4k) as in around the 180-190 mark, but cools right down when back to idling....

This is scary, something is restricting flow....

I know there is a factory restrictor that goes between the manifold and the riser...and i've had the riser off and saw NO obstructions in the riser, even used a coat hanger to run it through to act as a snake - nothing... and didn't see any in the manifold water jackets when i had the riser off....

my guess is im going to have to rip off the entire manifold to find a clog...

other thoughts?

 

[rodbolt]

Re: VIDEO! 1996 Volvo 3.0 GS - Cooling Hose Throbbing and Bursting

my guess would be a leaking head gasket allowing combustion gas into the cooling water passages.
a leak down test would quickly find it.

 

[Alpheus]

Re: VIDEO! 1996 Volvo 3.0 GS - Cooling Hose Throbbing and Bursting

my guess would be a leaking head gasket allowing combustion gas into the cooling water passages.
a leak down test would quickly find it.

+1

Thats exactly what I was thinking when I was that video...

 

[Don S]

Re: VIDEO! 1996 Volvo 3.0 GS - Cooling Hose Throbbing and Bursting

I think one thing you need to do is isolate where the restriction is. I have been looking at this for the last hour and have a theory.
You need to make a pressure gauge fitting and hook it in position A in the drawing below, run the engine and record the pressure. Then hook it up in position B and run the engine again at 3K. See if it's the same or close.
Somehow I bet there is a big discrepency between A and B.
Might be in the passageway in the upper part of the thermostat housing.

 

[4winnsskipper]

Re: VIDEO! 1996 Volvo 3.0 GS - Cooling Hose Throbbing and Bursting

I appreciate the responses guys

I did have the thermostat housing completely disassembled, all hoses, and main water pump on front of engine (circulating pump) and found no clogs.

A leak down test will be in order shortly. Thanks for advice guys

 

[4winnsskipper]

Re: VIDEO! 1996 Volvo 3.0 GS - Cooling Hose Throbbing and Bursting

update.

i dont have a leak down test but do have a compression tester.

ran compression test on all 4 cylinders, and was pleasantly surprised, here's the results with 2-4 seconds of cranking, motor was not cold but not fully warmed up. all spark plugs removed when tests conducted.

#1 - 179 psi
#2 - 182 psi
#3 - 175 psi
#4 - 175 psi


Now i know a leak down can find issues when a compression test cannot but these numbers are so close that im not sure there is a leaky head gasket, in addition, the plugs looked fine, no evidence of water.

i also noticed a bunch of other guys have had issues with this hose bursting on here.... so im not alaone but it seems the common theme is that they all tore up an impellar and chunks went through motor... now after tearing the thermostat housing apart, hoses, riser, the only place left is the manifold...

any more thoughts?