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| Thermostat on Volvo 5.7GSi https://www.smwebhead.com/phpBB3/viewtopic.php?f=6&t=8342 |
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| Author: | weather [ Mon Sep 05, 2011 6:57 am ] |
| Post subject: | Thermostat on Volvo 5.7GSi |
My port engine has decided it wants to run at 140 instead of the normal 170 or so that it used to run at. My first guess is a stuck open thermostat, although the other day we were out and ran it at 3500 rpm for 20 mins or so and it stayed at 140 - I would expect it to eventually get to operating temp the same way a car would? In any case, if someone can point me to the thermostat on my engines and give me a brief overview on replacement I would appreciate it. I've done this on cars many times, but boats are new to me. Steve. |
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| Author: | Cap'n Morgan [ Mon Sep 05, 2011 7:31 am ] |
| Post subject: | Re: Thermostat on Volvo 5.7GSi |
Look up your engine here on the parts diagram. http://www.marinepartseurope.com/en/vol ... using.aspx VP part # should be 3856961 http://www.powerproductsystems.com/pent ... =&Pageno=4 |
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| Author: | weather [ Mon Sep 05, 2011 8:09 am ] |
| Post subject: | Re: Thermostat on Volvo 5.7GSi |
Cap'n Morgan wrote: Look up your engine here on the parts diagram. http://www.marinepartseurope.com/en/vol ... using.aspx VP part # should be 3856961 http://www.powerproductsystems.com/pent ... =&Pageno=4 Thanks! Both great sites. I'm guessing I'll need a new sealing ring and gasket in addition to the thermostat. |
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| Author: | LouC [ Mon Sep 05, 2011 8:48 am ] |
| Post subject: | Re: Thermostat on Volvo 5.7GSi |
The thermo housing is held on by two bolts, first you remove the hoses, on top are the manifold hoses, on the left the raw water intake hose and there is the big hose to the circulation pump. Loosen the bolts most of the way and then grab the water outlet for the circ pump and pull up on the housing, that will usually break the seal for the gasket. Then unscrew the bolts the rest of the way, and lift up the housing. Remove the bolts, set em aside and turn the housing over. You will see the spring for the thermostat. Inside, probably covered with a layer of rust, is the rubber ring that fits into a groove that retains the thermostat. Pry this out with a small screwdriver. Then you can remove the thermo. The thermo goes in with the spring facing out, you really can't put it in wrong. Then drop in the rubber ring and work it into the groove. Next take a new gasket and coat it on both sides with gasket sealer that does not harden (I use OMC gasket sealer). Pick up the housing and put the bolts in, and screw them in by hand to make sure you don't cross thread them. I also put gasket sealer on the bolt threads, it keeps out moisture and prevents them from rusting in place. Tighten the bolts and reinstall the hoses. Done.... |
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| Author: | GTBecker [ Mon Sep 05, 2011 10:46 am ] |
| Post subject: | Re: Thermostat on Volvo 5.7GSi |
weather wrote: ... My port engine has decided it wants to run at 140.... Is that temperature determined from the helm instrument or with an IR thermometer? If the helm, you might want to verify that you don't have a bad sender before ripping into the engine. Replacing the sender is a little easier, too. |
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| Author: | Mario [ Tue Sep 06, 2011 3:31 am ] |
| Post subject: | Re: Thermostat on Volvo 5.7GSi |
It might be easier to just swap temp instrument cables round and see. |
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| Author: | LouC [ Tue Sep 06, 2011 5:42 am ] |
| Post subject: | Re: Thermostat on Volvo 5.7GSi |
Best thing to do first is pick up an IR temp gun from Radio Shack and check your temps, shoot it right at the intake manifold below the thermo housing, with the engine warmed up you should see 155-165 there. If not then it is the stat, if so then perhaps the sender, you can remove the electrical connection and make sure there is no corrosion on it before replacing... I've replaced a number of these stats over the years, what happens is a piece of rust from the raw water cooled engine gets in the stat and keeps it from closing. Sometimes all you have to do is remove it, put it in a pot of boiling water, it will open and release the chunk of rust and then it can work fine again... |
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| Author: | weather [ Tue Sep 06, 2011 8:34 am ] |
| Post subject: | Re: Thermostat on Volvo 5.7GSi |
LouC wrote: The thermo housing is held on by two bolts, first you remove the hoses, on top are the manifold hoses, on the left the raw water intake hose and there is the big hose to the circulation pump. Loosen the bolts most of the way and then grab the water outlet for the circ pump and pull up on the housing, that will usually break the seal for the gasket. Then unscrew the bolts the rest of the way, and lift up the housing. Remove the bolts, set em aside and turn the housing over. You will see the spring for the thermostat. Inside, probably covered with a layer of rust, is the rubber ring that fits into a groove that retains the thermostat. Pry this out with a small screwdriver. Then you can remove the thermo. The thermo goes in with the spring facing out, you really can't put it in wrong. Then drop in the rubber ring and work it into the groove. Next take a new gasket and coat it on both sides with gasket sealer that does not harden (I use OMC gasket sealer). Pick up the housing and put the bolts in, and screw them in by hand to make sure you don't cross thread them. I also put gasket sealer on the bolt threads, it keeps out moisture and prevents them from rusting in place. Tighten the bolts and reinstall the hoses. Done.... Thank you for the detailed description! Very helpful. |
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| Author: | weather [ Fri Sep 09, 2011 10:44 am ] |
| Post subject: | Re: Thermostat on Volvo 5.7GSi |
2 quick questions: 1. I'm thinking you can open up the thermostat housing while the boat is in the water - correct? 2. Torque specs on the housing bolts? Thanks, |
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| Author: | LouC [ Fri Sep 09, 2011 8:12 pm ] |
| Post subject: | Re: Thermostat on Volvo 5.7GSi |
You can but if your raw water intake hose is below the water line, water can siphon in. What I do, is I got some wooden plugs from West Marine designed to plug leaking through hulls. I just plug the raw water hose to be on the safe side. On my OMC the inside diameter of the raw water hose is 1", the Volvo I bet is the same because they use the same thermo housing for many years. Get some kind of a wood plug about that size. Torque on the bolts, get them good and snug, it just has to be tight enough not to leak. Like 20 ft lbs I'd guess. Make sure you use a non hardening sealer like OMC gasket sealer or Permatex Aviation sealer on the gasket and the threads of the bolts. That will make a good seal and the bolts will come right out next time.... |
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| Author: | weather [ Sun Sep 11, 2011 6:59 am ] |
| Post subject: | Re: Thermostat on Volvo 5.7GSi |
LouC wrote: You can but if your raw water intake hose is below the water line, water can siphon in. What I do, is I got some wooden plugs from West Marine designed to plug leaking through hulls. I just plug the raw water hose to be on the safe side. On my OMC the inside diameter of the raw water hose is 1", the Volvo I bet is the same because they use the same thermo housing for many years. Get some kind of a wood plug about that size. Torque on the bolts, get them good and snug, it just has to be tight enough not to leak. Like 20 ft lbs I'd guess. Make sure you use a non hardening sealer like OMC gasket sealer or Permatex Aviation sealer on the gasket and the threads of the bolts. That will make a good seal and the bolts will come right out next time.... Perfect, thanks for the advice. |
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| Author: | weather [ Sun Sep 18, 2011 3:33 pm ] |
| Post subject: | Re: Thermostat on Volvo 5.7GSi |
Just here replacing the thermostat and wondering if I need to let the non hardening gasket sealer set before running the engine? The bottle says nothing. Thanks. |
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| Author: | LouC [ Sun Sep 18, 2011 5:22 pm ] |
| Post subject: | Re: Thermostat on Volvo 5.7GSi |
Nope it's fine. |
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| Author: | weather [ Mon Sep 19, 2011 5:33 am ] |
| Post subject: | Re: Thermostat on Volvo 5.7GSi |
LouC wrote: Nope it's fine. Good to know. To be safe, and to not ruin what I just did, I left it until today before running water through it. |
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| Author: | LouC [ Mon Sep 19, 2011 5:57 am ] |
| Post subject: | Re: Thermostat on Volvo 5.7GSi |
The stuff I use (OMC gasket sealer) never hardens up, I have installed a Cobra impeller and used it on the housing gasket and ran the engine right after with no issues. This stuff is different than RTV, with that, it is a good idea to let it cure some. The thermostat replacement is an easy job on the Volvo or similar design OMC engines (actually, Volvo adapted the design used by OMC when they were in a joint venture some years back). I have to do it about every season because they start to stick open because of rust particles or sand getting caught in the stat and then it won't close and the engine never warms up. |
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