2008 3.0L thermostat housing sensors

[TBarCYa]

There are 3 sensors in the thermostat housing of my 3.0L and I need to replace all 3. I'm replacing the housing because the hose nipples crumbled when I tried to remove the hoses and so far one sensor broke on the way out, one appears to have damaged threads and won't thread into the new housing and the 3rd won't come out at all. Can anyone help identify these? If they're all temperature sensors, why 3?

Does this, including the "Frequently bought together" look like what I need? Two of the 3 look really close.

Amazon.com

View attachment 20220208_162551.jpgView attachment 20220208_162611.jpg

 

[Bondo]

Ayuh,.... Pics don't work,..... Serial number would be very helpful,.....

 

[TBarCYa]

For some reason my pics always show up as attachments... The SN is 1A020081

 

[TBarCYa]

I think I figured it out.... The red one is the switch for the buzzer, the other in that pic is for the gauge and the one that I can't get out of the old housing is the one that goes to the ECM. So, I'll order two of the 3 in that amazon link and I'll try to find the switch for less than $100.

 

[alldodge]

I think I figured it out.... The red one is the switch for the buzzer, the other in that pic is for the gauge and the one that I can't get out of the old housing is the one that goes to the ECM. So, I'll order two of the 3 in that amazon link and I'll try to find the switch for less than $100.

Correct on the first 2
Item 2 for Buzzer
Item 24 for gauge

Item 15 for is the TKS temp switch, which is part of the TKS carb control

https://www.mercruiserparts.com/bam/subassembly/30908/13603/150

Also looks like you need a thermostat housing

 

[Scott06]

Correct on the first 2
Item 2 for Buzzer
Item 24 for gauge

Item 15 for is the TKS temp switch, which is part of the TKS carb control

https://www.mercruiserparts.com/bam/subassembly/30908/13603/150

Also looks like you need a thermostat housing

What he said…and if your thermostat housing is that bad i would inspect your manifold and elbow carefully. I assume this is a salt water boat?

 

[TBarCYa]

What he said…and if your thermostat housing is that bad i would inspect your manifold and elbow carefully. I assume this is a salt water boat?

It is a salt water boat but the long block was replaced and it hasn't made it to the water yet. The thermostat housing was brought over from the original engine but the manifold, elbow and riser are new. The elbow deteriorated and let salt water into the exhaust ports which is why the long block was replaced.

 

[Scott06]

It is a salt water boat but the long block was replaced and it hasn't made it to the water yet. The thermostat housing was brought over from the original engine but the manifold, elbow and riser are new. The elbow deteriorated and let salt water into the exhaust ports which is why the long block was replaced.

Ok that’s what I was getting at re water damage due to bad exhaust

 

[TBarCYa]

Ok that’s what I was getting at re water damage due to bad exhaust

Unfortunately I've been through that. The boat spent the first 7 years in mostly fresh water and when I moved to FL the next 3 were in salt. In all of that time I didn't replace the elbow / manifold / etc and I paid for it. It died in 2018 and I'm just now getting it ready to go in the water due to a ton of other stuff going on.

On a positive note, the TKS temp sensor came out of the old thermostat housing so I was able to reuse that and the gauge sender.... Just waiting for the buzzer switch to show up.

 

[Scott06]

Unfortunately I've been through that. The boat spent the first 7 years in mostly fresh water and when I moved to FL the next 3 were in salt. In all of that time I didn't replace the elbow / manifold / etc and I paid for it. It died in 2018 and I'm just now getting it ready to go in the water due to a ton of other stuff going on.

On a positive note, the TKS temp sensor came out of the old thermostat housing so I was able to reuse that and the gauge sender.... Just waiting for the buzzer switch to show up.

Surprising only three years in salt would do it. I boat in the finger lakes in NY, unless you don’t drain it winterizing, they last the lifetime of the boat. On my old boat (3.0) i took the elbow off after 20+ years and it was fine.

 

[todhunter]

I boat in the finger lakes in NY

I've been to Keuka and Seneca and around Cayuga. Beautiful up there in the fall. Not sure I could handle the winter.

 

[Anthony Nardella]

I think I figured it out.... The red one is the switch for the buzzer, the other in that pic is for the gauge and the one that I can't get out of the old housing is the one that goes to the ECM. So, I'll order two of the 3 in that amazon link and I'll try to find the switch for less than $100.

I just went through this with my boat. I only know of two. The red one is for the over heat alarm. The smaller one is A temp sender to the gauge. Not sure about the third? You could look up the mercrusier manual on line. Lots of good repair information.