mercruiser 5.7 themostat housing temp sensor location

[tailwind 67]

I am in the process of rebuilding my engine. The thermostat housing required replacement. It is a seawater cooled open type system. I was told by the engine shop that Mecruiser changed the thermostat housing design. The new style is now the original style housing which I think is called a type 1. The housing I took off had a temp sensor at the 3 o'clock and 9 o'clock positions on the housing. The housing I just purchased and am trying to install, has holes for the sensors at the 3 o'clock and the 7 o'clock positions. The problem is that the one at the 7 o'clock position does not have enough room for the sensor to be installed. The intake manifold is too close. Has anyone run into this issue. This is the same housing that I earlier posted sticks out further to the front then the one I took off. This doesn't allow me to use the 12 o'clock hole in the water pump for my water heater tank return hose fitting but that is another issue. Right now I am focused on the temp sensors so I can get the housing installed. Thanks for any help

 

[Bondo]

Re: mercruiser 5.7 themostat housing temp sensor location

Ayuh,... It sounds like ya got the Wrong housing, all the way 'round....

 

[Don S]

Re: mercruiser 5.7 themostat housing temp sensor location

Post a picture of what you had, and what you got to replace it.
There has been many different housings over the years and different models of 5.7's

Oh, and post your engines serial number if you can. The engines have changed over the years too.

 

[tailwind 67]

Re: mercruiser 5.7 themostat housing temp sensor location

I found a Mercruiser Service bulletin (99-2) that references the housing replacement. My engine has the Bravo II stern drive. I found some part numbers on line for the housing I have and the one I took off. The one I took off was a 16413A with check balls. The one I purchased to replace it with is a 87290A23 I believe. I am at work so I'm unable to add any pics at this time, but will try when I get home. In the meantime, thanks again for any help.

 

[tailwind 67]

Re: mercruiser 5.7 themostat housing temp sensor location

This is the first time I have posted pics so hopefully it works. The old one is on the floor. The new one is on the engine just sitting there. It is viewed from the right side. You can see the temp sensor on the far side touching the intake manifold. The housing is not fully in place as it can't quite go far enough back because of the sensor and manifold interference.

 

[Don S]

Re: mercruiser 5.7 themostat housing temp sensor location

The sensor touching the intake manifold is your alarm switch. Remove it and plug the hole.
If you look just below the temp sender (foreground) there is a pipe plug in the intake. There should also be one on the other side of the intake but out of view in the picture. Remove that plug and using a reducer bushing if needed, put the temp alarm switch directly into the manifold. If the wire isn't long enough, you can put the switch in the plug under the sender if you have room.
Just make sure you hook up the hoses in the correct place. Many have done it wrong.

 

[tailwind 67]

Re: mercruiser 5.7 themostat housing temp sensor location

Can I use the hole that is plugged on the right side of the engine driven water pump just under the housing for the alarm switch? It is the same size as the alarm switch. I was thinking of using the one in the intake manifold behind the housing for my water heater return since I can't use the original location on the top of the engine water pump due to the new thermostat housing over extending it by a bit. Again I appreciate the help. Thank you