Impeller replaced, now cooling hose expanding

lamintdog

Cadet
Joined
Aug 8, 2008
Messages
11
I have a 1996 Glastron SSV 175 w/ a 3.0L GS / SX Outdrive, raw water and manual steering. I shredded my impeller about a week ago. Replaced it with a new one. I think I'm having an issue as a result of cooling blockage/impeller bits - but am not sure...

There's a large "U" shaped hose b/w the T-housing and Circ pump on the block that expands a lot under pressure when I'm giving it gas, which makes me think flow is restricted going into the circ pump - but I never ran the boat in water with the engine exposed to watch and see if that hose normally expanded before I replaced the impeller...so I'm not sure if it's normal or an issue?

Is this normal?
Should it be expanding under throttle or is that some sign of partial blockage or a sign of an old hose?

Water does flow out the exhaust ports and through the exhaust manifold. I did start it and run it for about 15min w/ muffs and the temp gauge got up to about 170-ish and then fluctuated back down to aroud 150, then climbed back to 170 and back down so it appears the T-stat is working?

I have not looked in the exhaust riser yet for blockage which I will do tonight. I have heard people talk about the oil cooler as a place to check for blockage - but I'm not sure that my engine has this?

I did pull the circ pump off the block and checked it for impeller pieces which I did not find. Any other suggestions would be greatly appreciated. I will post my exhaust riser findings later.

Thanks in advance guys.
 

littlebookworm

Chief Petty Officer
Joined
Nov 30, 2007
Messages
574
Re: Impeller replaced, now cooling hose expanding

I'm not familiar with that particular engine; BUT, hoses do not normally exand or contract to any noticeable degree when you accelerate. You seem to have two problems: blockage in the cooling system, which is causing the temp to rise and the hose to expand under pressure; and, a weak hose, which is bound to burst soon. I would suggest you pull the hose and replace it. But first, pull the pump, thermostat housing and whatever is connected in that area to clean out what I would guess are the pieces of the impeller, which are blocking the cooling system. I'd suggest that once you clean it all out, you should backflush before connecting the new supply hose. Good luck and let us know what you find. Hy
 

chiefalen

Captain
Joined
May 18, 2008
Messages
3,598
Re: Impeller replaced, now cooling hose expanding

I'm unclear as to weather you took off the t-stat housing to check for pieces in there? First place i would look.

You have power steering? If yes, thats the second place i would look for pieces.

Did you pull the long hose running to the T-stat at the transom to see if pieces are in there?
 

lamintdog

Cadet
Joined
Aug 8, 2008
Messages
11
Re: Impeller replaced, now cooling hose expanding

Thanks for the replies guys - I didn't have email notification turned on (which is now) so I'll reply quicker in the future. I didn't think that hose expanding was normal...

I did not pull the T-stat housing (couldn't get the bolts undone), but I pulled all hoses off it and looked around in there with a flashlight and it was empty - no parts / pieces anywhere in there. The Tstat appears to be fine. Here's the thing - the U hose goes from the Tstat housing into the circ pump and it's expanding AFTER the Tstat housing - suggesting that something either in the engine or after the Tstat housing is causing the blockage.

I am going to look in the exhaust riser next. I have manual steering on this - no power steering....

I pulled the water intake hose from the transom running into the raw water pump (which is where I changed the impeller) and flushed it using muffs before starting the boat w/ the new impeler... pieces did come out of it...

How do I backflush this system? Thanks again-
 

lamintdog

Cadet
Joined
Aug 8, 2008
Messages
11
Re: Impeller replaced, now cooling hose expanding

Finally got to pulling the exhaust riser... Didn't see any parts/pieces of impeller caught anywhere in there... Went ahead and ordered a new "U" shaped cooling hose to replace the weak one that expands under pressure.

You mentioned backflushing the cooling system - Can you quickly describe how to do this? Are there any other areas I can check for partial blockage?

Thanks.
 
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