Jump to content

Welcome to TheMalibuCrew!

As a guest, you are welcome to poke around and view the majority of the content that we have to offer, but in order to post, search, contact members, and get full use out of the website you will need to Register for an Account. It's free and it's easy, so don't hesitate to join the TheMalibuCrew Family today!

Removing thermostat


james11music

Recommended Posts

Hi everyone. I have the carb'd 350 merc. tournament/ski engine in my sunsetter My temp gauge hasn't worked since i bought the boat 3 years ago and decided it was time to figure out what is goin on. I started by taking my t-stat housing off which wasn't a problem. The problem is that i can't get the t-stat out of the housing. I've tried pulling it straight up with channel locks on the top, cone shaped part of the t-stat and it seems that it is rusted in place pretty well...unless i'm doing it wrong. Would someone chime in with a similar experience or let me know what i need to do? Thanks for any help in advance.

James

Link to comment

Heat the outside of the housing with a hair dryer then, have your wife hit it with her purse.

Should come out.

If not, start soaking it in PB blaster for a couple of days.

Link to comment

Heat the outside of the housing with a hair dryer then, have your wife hit it with her purse.

Should come out.

If not, start soaking it in PB blaster for a couple of days.

So I can just hit it with a hammer from the bottom of the housing? I just wasn't sure if that would damage the housing or not.

Link to comment

Heat the outside of the housing with a hair dryer then, have your wife hit it with her purse.

Should come out.

If not, start soaking it in PB blaster for a couple of days.

Well, I hate to admit it, but the purse idea worked :biggrin: I just hit it harder with the hammer from underneath the housing and it knocked it loose. Pliers from there and it's out! Thanks for the quick reply

Link to comment

I was about to post warning you not to do that. Hitting it with your "purse" is a running joke. Glad to hear it came loose and hopefully nothing was damaged.

Only the thermostat was bent out of shape once i removed it. It was wedged pretty tight. after throwing in it in some hot water it still opens up( not sure at what temp though). I need to pick up a thermometer.

Link to comment

For peace of mind, just buy a new thermostat. 160 degree. Sounds like you may need a temp sending unit though, or the guage may be flaky, or the umbelical wiring harness may need pulled apart, spray with contact cleaner, then put back together.

Steve B.

Link to comment

Had a similar issue as the temp gauge didn't work when I bought the boat used last year. Ended up replacing the entire cluster gauge (bought from Bake's) and started getting a reading right away. Engine seemed to run generally cool around 130 degrees so I figured I had another issue. Removed 10 year old thermostat and found it had degraded and broken into three pieces inside the housing. Water was just passing right past the thermostat and not allowing the engine to heat to proper operating temp. Replaced with 160 degree thermostat and all is well again.

Link to comment

For peace of mind, just buy a new thermostat. 160 degree. Sounds like you may need a temp sending unit though, or the guage may be flaky, or the umbelical wiring harness may need pulled apart, spray with contact cleaner, then put back together.

Steve B.

Good idea. I was planning on replacing the old t-stat anyway(due to how much i munched it up getting it out of the housing), but i wasn't sure if i needed a 140 tstat or a 160. Now i know(160). thanks a bunch. Now for the fun part, Diagnose(temp sending unit, wiring, or gauge). Is there a way to test the temp sending unit once i pull it out of the t-stat housing?

Link to comment

See post #8 here if you have a stubborn one again. Best not to strike the cast if you can, a chisel is your friend. This post I suggested is complete with pictures and worked very well for my stubborn T-stat housing:

Link to comment
  • 3 weeks later...

Heat the outside of the housing with a hair dryer then, have your wife hit it with her purse.

Should come out.

If not, start soaking it in PB blaster for a couple of days.

Funny!!! hit it with her Purse!! Good Stuff!! :lol:

Link to comment

Good idea. I was planning on replacing the old t-stat anyway(due to how much i munched it up getting it out of the housing), but i wasn't sure if i needed a 140 tstat or a 160. Now i know(160). thanks a bunch. Now for the fun part, Diagnose(temp sending unit, wiring, or gauge). Is there a way to test the temp sending unit once i pull it out of the t-stat housing?

If you have a variable resistor that you could put in-line you could test it. Or, turn on the key on, check the gauge, remove the sending unit wire and the gauge should pin one way or the other. Or, with the new sending unit, you could connect it to the wire, turn on the key, and submerge it in water about 160 or so. If you check the temp with a thermometer, you should be able to see how accurate it is too. Sounds like it may work.

Link to comment

Pull the wire off the sending unit and ground it directly to the engine with the key on. If the gauge responds replace the sending unit. If not, then it is either the gauge or the harness.

Link to comment

If you have a variable resistor that you could put in-line you could test it. Or, turn on the key on, check the gauge, remove the sending unit wire and the gauge should pin one way or the other. Or, with the new sending unit, you could connect it to the wire, turn on the key, and submerge it in water about 160 or so. If you check the temp with a thermometer, you should be able to see how accurate it is too. Sounds like it may work.

Thanks for the help. I have a new t stat on the way. Once i get it i will put it back together along with the battery/impeller and start trouble shooting with Ruffdog's and your ideas. It will probably be a couple weeks, but i'll keep you guys updated. Thanks again!

Link to comment

I also meant to ask, what are the two different temp sensors on the thermostat housing. I know one is the water temp sending unit, but not sure on the other or which is which?

Link to comment

I also meant to ask, what are the two different temp sensors on the thermostat housing. I know one is the water temp sending unit, but not sure on the other or which is which?

Do you have a pic? I only have 1.

Link to comment

Do you have a pic? I only have 1.

I'll have to take a picture on my lunch break. There is a sensor on the port side of the housing which is a little smaller in diameter and a sensor on the starboard side which is a little larger in diameter. I have two separate wires going to the T stat housing.

Link to comment

I'll have to take a picture on my lunch break. There is a sensor on the port side of the housing which is a little smaller in diameter and a sensor on the starboard side which is a little larger in diameter. I have two separate wires going to the T stat housing.

Mine is starboard side with a single wire.

Link to comment

Thanks for the help. I have a new t stat on the way. Once i get it i will put it back together along with the battery/impeller and start trouble shooting with Ruffdog's and your ideas. It will probably be a couple weeks, but i'll keep you guys updated. Thanks again!

I should add that the gauge should peg out when you connect the wire straight to ground.

Link to comment

Does anyone know which sensor is the water temp sending unit and/or what the other sensor is. Any help would be greatly appreciated.

James

the top pic looks like my temp sending unit, just on the opposite side from mine. The bottom pic, is that just a barbed nipple for some sort of tubing?

Link to comment

the top pic looks like my temp sending unit, just on the opposite side from mine. The bottom pic, is that just a barbed nipple for some sort of tubing?

No, it's some sort of sensor. There is a wire connected to it( obviously not in the pic) along with another wire connected to the sensor in th first pic( apparently the temp sending unit). Does anyone know what the sensor is in the second pic i posted of my Tstat housing (starboard side)? You might be able to get a better idea of what is what by looking at the third pic...or link to pic. Thanks for the reply

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...