merc 3.0l thermostat

[ANDREW SMITH]

Iboaters.....did Mercury change the t-stat from 160 to 185F, and if so when? My 3.0L runs very happily at about 190 on the guage, but the manual says the t-stat opens at 160F. I am still in the first 10 hours of break in period when the motor may have more friction and run hotter. Thanks for your help.

 

[kozman01]

Re: merc 3.0l thermostat

RR, did you check out my reply to your post in my previous thread "What tool do I need to so this"? I think they changed that thermostat in 02' Not positive, but I think that's the year. What year is your 3.0? If it's an 04' like I think you have, the therostat is stainless-steel and is fully open at 185. I get similiar readings on my 3.0 w/ 6 hours, maybe a little cooler, but not much.

 

[vipzach]

Re: merc 3.0l thermostat

I don't want to jack your thread, but mine never reads over 140 on the gauge. I have a 91 merc 3.0

 

[tommays]

Re: merc 3.0l thermostat

i have never heard of of anything over a 160 on a raw water cooled motor<br /><br /><br />only a FWC motor (heat exchanger)<br /><br /><br />tommays

 

[kozman01]

Re: merc 3.0l thermostat

My info. is straight out of the manual<br /><br />3.0L<br />Standard cooling Serial # 0L340999-Prior (brass thermostat)<br /><br />Starts to open 143 deg<br />Fully opened 168 deg<br />Cool down closed 133 deg<br /><br />3.0L<br />Standard cooling Serial # 0L341000-On (stainless steel thermostat)<br /><br />Starts to open 160 deg<br />Fully opened 185 deg<br />Cool down closed 150 deg

 

[ANDREW SMITH]

Re: merc 3.0l thermostat

Koz, my boat is a 2005, manufactured in november of 2004. The merc owners manual says t-stat operates at 160f. Could be the manual is out of date? I'll check the engine serial number to-night to confirm, thanks for your help.

 

[kozman01]

Re: merc 3.0l thermostat

I'm not sure. My Clymer manual goes up to 04'. My 04' has the stainless thermostat that opens at 185 and the temp gauge shows that.

 

[tommays]

Re: merc 3.0l thermostat

the biggest mistake you can make is to take FACTS from a clymer manual<br /><br />get the facts from merc they built the motor <br /><br /><br />tommays

 

[kozman01]

Re: merc 3.0l thermostat

I'll agree with that. My temp gauge still reads approximately 185 then cool down begins. Anyone else have any input as to what the MErc manual says on this?

 

[tommays]

Re: merc 3.0l thermostat

i have the older 143 stat it never goes over 150 but its not like the guages are Calibrated<br /><br />it has been covered here by don,s a bunch of times but i dont remenber his exact words a 3.0 stat search may find it<br /><br /><br />tommays

 

[kozman01]

Re: merc 3.0l thermostat

I hope it's not a defect or something else, but we've got two new 3.0 on this thread alone running at around 185.

 

[kozman01]

Re: merc 3.0l thermostat

I just got a call back from the dealer and he says that my 3.0 has the 160 deg. thermostat. Now I need to find out why I'm operating in the 180 range. Any ideas from anyone? I'm also going to have to find a way to contact CLymer and advise them of their obviously incorrect data in their manual. Mercruiser Stern drive shop manual: 1998-2004 Alpha, Bravo One, Bravo Two and Bravo Three Catalog # B745-2 page 114

 

[tommays]

Re: merc 3.0l thermostat

well it cant even open until 160 and does not fully open until 185 <br /><br />i dont like it but it seams to be correct and nessary for the newer motor to meet emmisions standards<br /><br />the real question is what does merc say eather they think its normal or not<br /><br />tommays