Jump to content

Overheating / temperature sending unit?


RD9

Recommended Posts

5.7l 350 mpi horizon mercruisrr 2003. 
 

my port motor as soon as motor gets to 3500 the over heating sensor alarm comes on not running just below this the motor will run as normal. I’m getting water because the top of the motor stays cool and have coolant.   Gauge is reading under the overheating mark. 
 

I did some research seems like temp sending might be issue. Anything else I could look at? Or suggestion?

 

thanks in advance guys. 

Link to comment
Share on other sites

I'm assuming it's twins, switch senders from one to the other and see if the starboard engine does the same with the port sender in it . Not often they go bad but it could save a lot of needless time & $ in the end.  

  • Like 1
Link to comment
Share on other sites

It is twins but each motor has a different sensor. I originally thought impeller but I have water, maybe it’s just getting week. 

Link to comment
Share on other sites

I would get a infra red with laser light and compare the two engines over varying speeds. Had a burning smell we couldn't figure out , turned out to be the rubber hose coming off the exhaust manifold. The Temp gauge was always ok because it ran off the top of the intake manifold which was part of the closed cooling system. The exhaust was not part of that reading and the raw water elbow going into the manifold was blocked up with crud , the heat gun showed it.

 

Link to comment
Share on other sites

I should think hanks advice should be the first and most straight forward thing to try before getting too far down the pike:smile:

  • Like 1
Link to comment
Share on other sites

On 3/27/2020 at 10:54 AM, L&M said:

I'm assuming it's twins, switch senders from one to the other and see if the starboard engine does the same with the port sender in it . Not often they go bad but it could save a lot of needless time & $ in the end.  

I got you I first read this post incorrectly. Thank you that’s good advice. 

Link to comment
Share on other sites

On 3/27/2020 at 6:17 PM, Bozeman Bob said:

I would get a infra red with laser light and compare the two engines over varying speeds. Had a burning smell we couldn't figure out , turned out to be the rubber hose coming off the exhaust manifold. The Temp gauge was always ok because it ran off the top of the intake manifold which was part of the closed cooling system. The exhaust was not part of that reading and the raw water elbow going into the manifold was blocked up with crud , the heat gun showed it.

 

Thank you I have read about issues in manifold. 

Link to comment
Share on other sites

23 hours ago, lakebound88 said:

I had this happen on my crusaders. Was just my sensor after verifying with my temp gun... replaced it an never returned. Good luck!

You also stated alarm, is your alarm also linked with oil pressures too?

Sent from my SM-G960U using Lake Ontario United mobile app
 

It is but I have an oil pressure gauge on dashboard. I’m replacing impeller will it’s in yard and temp sending unit. Impeller If not needed to be changed will end up needed to be changed at some point. Better now then while out on lake. 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...