1994 Volvo Penta 5.7L GL Hydrolock

[gonebroke]

Ive got a 1994 5-7L gl VP sterndrive in a Chaparral Sunesta 220 w/ DP outdrive. At the lake for 5 days last week. 1st 2 days ran fine. 3rd day started overheating , got around 210 and I shut it off and waited to cool since I was in eyesight of camp. Let cool and pulled freshwater pump checked newly replaced impellor and reinstalled. Turned key on and temp was at 160, started boat and slowly climbed to 200 and again I shut it off. Next I pulled thermostat out looked old but still functioned. Boiled water in microwave so I have no idea what temp it was but the thermostat openend none the less. re installed thermostat and again 200. next i took the thermostat out and left it out. this only took a few minutes so when i restarted the boat the was 195 within 1 min it dropped to 140 deg. and stayed there till the last night we were there when i went to fish i pulled out of the cove barely got to plane the slowed down to wake speed for about 5 min then the motor just shut off. i restarted it ran for maybe 3 sec then shut off again. it did this like 5 times then the last time it just went clunk. towed her back to shore the next morning thinking it was batterie/electrical related i put 2 new batteries in her and same clunk. got her home and pulled the sparkplugs and water in all 8 cylinders. cranked for approx 30 sec to blow water out then blew out with hp air.and sprayed 1/3 can "liquid wrench" in each cyl.again rotated motor several times and now shes sittin out front waitin..............I have read alot about water coming in via the "Y" pipe and throught the risers. but i have also read some about the exhaust risers being compromised or the gasket being blown. i also saw a Volvo Penta service advisory about hydrolocking after overheating caused by loosening of the riser to manifold bolts. And some say intake manifold. Where would you guys start? Dont really want to throw money at it blindly. I pulled #s off of it but im pretty sure its an aftermarket engine cause i found a plate on the front of the motor that says "Vulcan Automotive equipment #48218" not sure how good that is being this is a boat not an autombile. And 5.7GL is on the spark arrestor cover that om sure came off the original motor. I sent Vulcan an email requeting mfg date,specs, etc. Any thoughts. Thank you in advance for your help.

 

[Don S]

Re: 1994 Volvo Penta 5.7L GL Hydrolock

Riser to exhaust manifold gasket leaking, they go bad during an overheat. Is this a salt water boat? If so the manifolds or risers may be plugged up causing the overheat.

 

[gonebroke]

Re: 1994 Volvo Penta 5.7L GL Hydrolock

No Sir, to the best of my knowledge it has never been in salt water. Been in AZ its whole life. I pulled risers off and took to locasl shop and was told they "look" good and he explained how to bench test bu filling water holes with solvent and checking for moisture in gas chambers. He also explained how to test manifolds. Which I will do tonight. We are also gonna do compression test and a leak down test. But the likelieness of blowing a head gasket across all 8 is not good from what Ive been told? I was also told if it was the intake manifold I would surely see water in the oil which I do not have. I read alot about the lack of baffles in VP motors but Ive had this boat out already about 8 times just in 2011 and have yet to experience this problem. Should I consider using something diff than a "Sierra" gasket? I live in Az and the water at the lakes I go to rarely goes below55 or so and dead of summer gets to 90. Do I still need a thermostat? Can you media blast your risers and manifolds to clean. Can you hot dip them? Again Thank you for the reply.

 

[gonebroke]

Re: 1994 Volvo Penta 5.7L GL Hydrolock

replaced all the gaskets and she runs great . the starboard side gasket was the only one compromised can it fill all 8 with only one side compromised?

 

[JoLin]

Re: 1994 Volvo Penta 5.7L GL Hydrolock

To answer one of your questions, yes, you need a thermostat. It's designed to allow the engine to reach optimal operating temperature and stay there. 140 deg. operating temp. is too cold. It wastes fuel and fouls plugs.