Mercury MerCruiser 3.0 thermostat

Mercury MerCruiser inboard 3.0 change thermostat, tighten alternator power steering belt

[@davidodonnell1681]

Thank you! You saved my day! My mechanic had installed the thermostat upside down - it turns out. Thanks to your video I could fix it and get back on the water! Now I need to go check the belts also :-)

[@yooper233]

Glad it helped. It is hard to figure out a problem when you install new parts and it still doesn't work. I have seen that problem on cars before.

[@TAHerrmann1]

Thanks Yooper! Most helpful. I used a slapper with a puller jaw to coax the thermostat sleeve (as it's called) up. I placed the jaw under one of the openings, tap tap, then the other. Moved up enough to grab hold and pull it out intact. Cleaned everything as you did and then rubbed a little silicone grease on the outside to make things easier next time. Thanks for the help. Now I'm ready for the Fourth of July weekend!

[@yooper233]

I was visiting some friends in Florida so I didn't have all my tools with me. The funny part is the problem ended up being the tempt sensor was just making the gauge read high. The thermostat needed to be changed any way because it was a little corroded and probably prevented a future over heating issue. Glad it helped and hope you had a good Fourth.

[@davidvo30]

Thank you. Great info video. I have the same engine and this helped. Much appreciated for you taking the time to make this available.

[@mvanderw379]

Thanks for posting, doin mine right now!

[@MR-sw7zk]

Hi Yooper had my mechanic checking on my boat, temp was reading 175. He did mention replacing the thermostat. Not only I learned where the thermostat is located but another reason for the high temp. Now I will have to find out where is the tempt sensor on my boat just in case. Thanks for sharing this video

[@yooper233]

M R The temp sensor should be located just below the thermostat. I think it is the brass one.

[@MR-sw7zk]

@@yooper233 Oh ok. Thanks for the information.

[@MR-sw7zk]

@@yooper233 Hey Yooper, I just replace the thermostat, ran for a few minutes, temperature went up to 175 is that a normal temperature ? Or should I just got ahead and replace the sensor ? Please advice, Thanks.

[@wayneclark4106]

Hack saw method work excellent.

[@laurentmoser]

Ciao, ogni quanto lo cambi te? Cari saluti dalla Svizzera 🇨🇭 😊

[@yooper233]

di solito solo quando il motore è surriscaldato ma puoi cambiarlo se vecchio in modo da non avere problemi futuri. spero che questo sia stato tradotto correttamente.

[@southo69]

Sensational - cheers

[@MikeDoerr]

Do you remember if there was a gasket below the thermostat? I did not see one but thought it looked like there could be one....seeing if you had to add something after the video or not?

[@yooper233]

Mike Doerr I don’t think there was. Sorry for the late response.

[@MikeDoerr]

@@yooper233 thank you!

[@peteranania7166]

There's a gasket below the thermostat but not worth the effort of chopping it out and cleaning it.

[@ElGordo_831]

Hey pal I have a 1986 stingray 3.0 omc and my temperature keeps rising up to 210-220 degrees, I know that’s not normal. Someone told me that it can be the head gasket? What do you think?

[@yooper233]

Mr. Nobody I would start with the thermostat if it has not been changed. If you remove the spark plugs look at them and see if one of them looks fouled like it’s not firing. You could also do a compression check on each cylinder to see if you have one with low compression which could be a head gasket.

[@yooper233]

Sorry for late reply but in my opinion if head gasket I would take to a professional and have them check compression.

[@Middlemcd]

what year engine is this? mine looks a lot like yours but i am trying to determine what year engine I have.

[@yooper233]

It is a 2005. It was a friends boat so I was just working on it while on vacation.