1996 Volvo 5.0 SX water pickup question/overheating

[ZZ3Astro]

Hi all,<br /><br />I just purchased a 96 Sunbird Corsair with a Volvo 5.0 and SX drive. Yesterday was the first real sea trial (the one after you've paid!). A big problem with cooling has emerged and I wanted to ask a couple of questions about the flow of water through the drive pickup. It cools fine at idle up to about 2000 rpm. By 2500 rpm it's running 180-200 and anything over that will peg the needle. I can only imagine how many times the previous owner might have done this. <br /><br />Out of the water she comes..<br /><br />With the engine off, drive tilted up, raw water line disconnected from pump, if I connect the flushing device to the outdrive, water begins running out of the exhaust opening at the bottom of the transom plate. I've confirmed the water is coming from the drive because I can push upward on the exhaust bellow and the water stops running out of the transom plate. Also, if I tilt the drive down, the water flows from the center of the prop. Is this by design? It seems to me if there is such a direct connection between exhaust and raw water, the pressure of the exhaust would feed right into the raw water pump and cause this overheating...<br /><br />Next problem.. If I really turn up the water pressure to allow the level of water in the drive pickup to reach the hose that connects the raw water pickup to the transom, water starts running out from where the hose connects to the back of the drive. There is so much water leaking through the exhaust and this second leak, I have yet to see water flowing to the raw water pump from just waterhose pressure alone.<br /><br />Now I admit I know little about these SX drives, but none of this seems logical to me, if you're looking for a cool running engine..<br /><br />To make matters worse, after running for a while yesterday I have a bad vibe starting.. lot of noise from the drive during flushing last night while in nuetral. I'm guessing u-joint if I'm lucky or bearings if I'm having a streak of bad luck.<br /><br />Anyway, just looking for some ideas... Of course I plan to change impeller, etc but the weird water flow patterns have me concerned. Thanks for any input...<br /><br />steve

 

[Lou C]

Re: 1996 Volvo 5.0 SX water pickup question/overheating

Sounds like you have to pull off the drive and check out the water feed tube from the od to the transom housing. These Volvos are just like my old OMC in that regard. Then it sounds like you need to check the u-joints, gimble and bellows while you are in there. Finally, look at the impeller (mounted on the engine). <br />Did you sea trial it before you bought it, and did it overheat then?<br />I'd get a Volvo shop manual before you start pulling stuff apart.

 

[ZZ3Astro]

Re: 1996 Volvo 5.0 SX water pickup question/overheating

We did run it with the flush adapter at his house and I noticed what seemed to be a lack of water from the prop.. but then we noticed the water exiting from the transom plate. More research showed this is a normal exit location for the exhaust so I made the assumption at that time that the water coming from the exhaust was going through the engine. Because of this, the next day we did a sea trial and we checked the temp several times and it was ok... however the GPS unit is mounted directly in front of the temp gauge and when we were under full power I was looking at the speed and depth. In hindsight, I should have checked the temp while at full speed. When you come off plane, it cools back down quickly. After we slowed down from a hard run, the temp was around 185.. but we spent a couple of minutes running slow while doing something with the gps. <br /><br />Next time I'll know what to watch for more closely! <br /><br />steve

 

[ZZ3Astro]

Re: 1996 Volvo 5.0 SX water pickup question/overheating

Well I couldn't take the pressure any longer. I removed the drive and found the problems... and there are many, all traceable back to the shoddy mechanic the previous owner spoke so highly of. There is a rubber block that seals the raw water between the upper and lower parts of the drive.. that block was improperly installed which caused it to be completely in the exhaust stream, which dried it out and made it shrink, allowing the exhaust hot water to enter the raw water pickup. Also tons of orange silicone RTV on seals that should have been replaced instead of rigged!<br /><br />I fed water directly into the raw water pump and the engine runs 150 now at 5000 rpm all day. However the raw water pump is now leaking, traced back to a stripped screw that was being held in with orange rtv. Since the pump hasn't seen enough water to make any pressure for all this time, the steady feed of water made pressure and pushed the bolt out of the stripped hole.<br /><br />This is turning into a $6000 lesson, not counting the money I may have to put into it to fix any damage that may have occurred. Ouch!<br /><br />steve<br />

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