what thermostate do i need?

[dgopetactical]

1987 mercruiser 5.7 alpha 1

I was replacing manifolds and bad hoses today and when i opened up the thermostat it was so coroded i deceided to replace it. I cant find any numbers on it and when i took it to auto zone for a replacement they needed more info. what temp thermo-stat do i need? and can I get this at a regular parts store? Just started doing it myself this year so im a little green. please help.
Thanks,
Denny

 

[Scaaty]

Re: what thermostate do i need?

You need marine specific, not auto. A raw water cooled will be a 140 degree, not sure which one for enclosed system (probably a 160 degree). Someone will come along here and add more info...

You need to tell us if raw cooled, or inclosed..

 

[Don S]

Re: what thermostate do i need?

With a raw water cooled cooling system, stick with a good quality marine thermostat. Automotive stuff runs in antifreeze and corrosion and rust isn't a problem.
You need Mercruiser #807252T 1 which is a 140? thermostat.

 

[dgopetactical]

Re: what thermostate do i need?

I have a raw water system. thanks for the quick reply. does the sleeve come with the stat or is that seperate? mine dont look healthy and i might as well replace it. Thanks for all the help guys.
Denny

 

[Don S]

Re: what thermostate do i need?

Nope, no sleeve. You should also replace all orings and gaskets on the thermostat housing. There are 3 designes for that housing so it's impossible to know which one you have to give you part numbers for the gaskets and orings or sleeve for that matter.

 

[dgopetactical]

Re: what thermostate do i need?

Nope, no sleeve. You should also replace all orings and gaskets on the thermostat housing. There are 3 designes for that housing so it's impossible to know which one you have to give you part numbers for the gaskets and orings or sleeve for that matter.

i will take the housing in with me to match the correct gaskets. O-rings? i see no place in the housing that there was o-rings or where o-rings should go. I have a cross section picture and i see no o-rings just 2 gaskets, stat and check valves on top where the hoses come in from the circulating pump. where am i missing the o-rings?
Many thanks,
Denny

 

[Don S]

Re: what thermostate do i need?

http://dougrussell.com/partscatalog... GM 350 V-8 1987-1995&index=1014


Scroll down to design I, II, or III

One note, you should be going by serial number not year. You could have an 87 boat with a 86 motor since the year changes are different for boats and engines. The link above is basically 87 to 95.

 

[dgopetactical]

Re: what thermostat do i need?

Re: what thermostat do i need?

http://dougrussell.com/partscatalog... GM 350 V-8 1987-1995&index=1014


Scroll down to design I, II, or III

One note, you should be going by serial number not year. You could have an 87 boat with a 86 motor since the year changes are different for boats and engines. The link above is basically 87 to 95.

Thanks for your help. I have design III. I do have a 87 motor. Last year you (don) helped me with another problem and i provided you with a s/n. i have a 88 boat with a 87 motor.
Denny

 

[Don S]

Re: what thermostat do i need?

Re: what thermostat do i need?

Great, then I guess you know which gaskets you need. But stick with the 140? if in salt or brackish water. The 160 causes to much build up and corrsion.