VOLVO AQ131A OVERHEATING MAKING ME NUTS

[STYP]

I HAVE AN 1987 VOLVO AQ131A IN A 20 FT IMPERIAL CUDDY CABIN. I BOUGHT IT NEW. THIS ENGINE HAD OVER HEATED FROM THE FIRST SEASON I HAD IT. THE DEALER SAID HE HE FIXED AFTER KEEPING IT FOR 4 WEEKS,THEY NEVER DID. THE NEXT YEAR THE SAME PROBLEM, EXCEPT THE DEALER SHIP CLOSED DOWN. VOLVO WOULD NOT COVER THE 1 YEAR WARRANTY.<br /><br />HERE IS THE PROBLEM: THE ENGINE RUNS AT 180 WHEN NOT UNDER LOAD. WHEN UNDER A LOAD ABOVE 2500 RPM THE TEMP HITS 180 AND THE THERMOSTAT OPENS BUT AFTER THAT THE TEMP WILL JUST KEEP CLIMBING PAST 240 UNTIL I SLOW IT DOWN. I HAVE CHANGED EVERY COMPONENT IN THE COOLING SYSTEM. I HAVE PUT IN A CLEAR HOSE FOR THE SEA WATER PUMP. NO AIR IN THE SYSTEM EVEN AT HIGH SPEEDS. EVEN AT ENGINE TEMP AT 230 YOU CAN KEEP YOUR HAND ON EXHAUST MANIFOLD AND IT WILL ONLY BE WARM TO THE TOUCH. I HAVE FLUSHED OUT THE ENGINE SEVERAL TIMES FROM TOP TO BOTTOM CHANGED WATER PUMP AND THERMOSTAT. HAD THE COOLING CORE BOILED AND CLEANED. CHECKED TEMP WITH A MEAT THERMOMETER, PUT IN A NEW TEMP SENSOR AND GUAGE. HAVE CHANGED THE TIMING BELT AND RESET THE TIMING WITH A GUN<br /><br />AMAZINGLY THE ENGINE RUNS GOOD, STARTS EVERY, TIME, RUNS SMOOTH. <br /><br />I HAVE HAD THIS PROBLEM FOR 17 YEARS AND I AM DETERMINED TO SOLVE IT THIS YEAR, OR ADD IT TO THE FISHING REEF IN LAKE ERIE, EVEN A VOLVO AUTHORIZED MECHANIC GAVE UP ON IT.<br /><br />ANY SUGGESTION WOULD BE APPRECIATED

 

[Don S]

Re: VOLVO AQ131A OVERHEATING MAKING ME NUTS

Please, if you would, edit your post and leave off all the caps. Makes it so hard to read I won't even try......Ok, I'll try.<br />Check the seal on the hose connection at the drive. It's held on with 2 allen head bolts. If the seal is out of place or missing, when you get on step it's out of the water and the pump sucks air instead of water and you get an overheat.<br />Items 24, 25, and 26 below.<br /><br />

 

[STYP]

Re: VOLVO AQ131A OVERHEATING MAKING ME NUTS

Sorry I am used to making mechanical drawings where every thing is in capital letters. Anyhow yes I have tried this and I am not getting any air into the system

 

[Don S]

Re: VOLVO AQ131A OVERHEATING MAKING ME NUTS

You mentioned you changed the water pump, did you mean the raw water pump, or the engine cirulation pump.....or both. I have seen the impeller in the engine circulation pumps become loose on the shaft and not spin at the higher rpm.

 

[Hog Wild]

Re: VOLVO AQ131A OVERHEATING MAKING ME NUTS

So I take it you have checked the Thermostat in a hot water bath to see that it opens? And it opens at what temp? And I take it you believe you have the correct thermostat installed.<br />Have you run the engine on "muffs" on land and does it suck in a whole bunch of water (like the entire garden hose volume almost at above a 1000 rpms).. Don't go much over like 1000 - 1500 rpms on the muffs. I'm just setting the tone for water volume flowing through the system. How hot does the water flowing out of this engine feel when it's up at 180 deg.? This is a fresh water cooled boat? I am most absolutely positive that this is a water flow problem. Not enough water flowing through the engine when it needs it. So just a detail to find the cause.. How fast does it cool down when you slow down, really fast or does it take awhile. Have you had a good 2nd opinion from a good shop. Are all parts factory correct, water pump pully is correct size (again affecting water flow). If this one is really a "stumper" then you might need to measure flow at each and every hose and compare to manu'f recommended flow there.

 

[johnkc]

Re: VOLVO AQ131A OVERHEATING MAKING ME NUTS

ok i'll ramble here for a minute,when i get a 131 that is over heating ?<br />check impeller vanes and make sure the brass hub is not spinning inside the rubber,seals good on the impeller shaft?<br />is the thermostat the correct oem stat?have had some will fit after mkt that don't work on closed cooling.<br />is the antifreeze mixed 50/50?<br />reference#11 on dons post,if this bushing is bad it will take out #25 and cause air bubbles in your clear hose.<br />make sure there is not an air leak between your clear hose and the sea water pump.<br />remove the front cover of the heat exchanger box and remove the heat exchanger core and inspect.<br />i know i have repeated some of the others suggestions and you have already done most of this ,just trying to help .good luck

 

[Dunaruna]

Re: VOLVO AQ131A OVERHEATING MAKING ME NUTS

Just some observations,<br /><br />I find it interesting that the problem has been with you since the boat was new, 17 years!<br /><br />Could the problem possible be that the dealer fitted the wrong heatexchanger ? Or maybe the wrong temp sensor/gauge combination ? You said that the manifold is only warm to the touch, maybe your gauge is reading incorrectly.<br /><br />Aldo