H20 Pressure Sensor - where is it?

PMC

PMC

Well-Known Member
Apr 10, 2009
1,454
Long Island, NY
Boat Info
2001 40 Sedan Bridge
Engines
Cummins 6CTA
I received an alarm from the SmartCraft gauges - indicating there was a Water Pressure Sensor Fault

Here is what I know
-The Impellers were changed 7 hrs ago
-I continued to run the engines - 2 hrs more - the temp did not move
-The risers are cool to the touch

I'm fairly certain that it is a faulty sensor and nothing mechanical, but I don't know where to locate the pickup. :huh: Can you assist?

Also recommend a good repair manual - so that I don't ask too many silly questions...

I'm sure this info (especially the Manuals) have been discussed here before - I'll need to master the search a little better.
 
OK - Ill back up here - Is there a water pressure sensor?:huh:


Raw water cooling - Single point block drain (if that helps)
 
No info - Anyone? Repair Manual recommendation? You guys stink!
 
OK, I looked at bammarine.com on their parts pages and can't even find a water pressure sensor for a 4.3 no matter which version I choose. Your raw water pump does look quite similar to the ones on my 8.1's, which have the sensor on the pumps itself. Are you familiar with the raw water pump on your engines? If so, do they have any kind of sensor on it? If so, it's the pressure sensor. Can't help anymore, I'm just not familiar with the 4.3's. I'm surprised you haven't gotten a definite answer yet myself with all the 280 owners around here :huh:
 
This boat has Alpha I drives - the pump or impeller is in the lower unit.

I'll be looking tomorrow with a mirror - I think it may be on the Port side of each engine - tucked under very low.
 
PMC said:
Here is what I know
-The Impellers were changed 7 hrs ago
-I continued to run the engines - 2 hrs more - the temp did not move
-The risers are cool to the touch

I'm fairly certain that it is a faulty sensor and nothing mechanical, but I don't know where to locate the pickup. :huh: Can you assist?

Also recommend a good repair manual - so that I don't ask too many silly questions...

I'm sure this info (especially the Manuals) have been discussed here before - I'll need to master the search a little better.
Click to expand...


That is a long, long, long time for an Alpha impeller to be in service....depending on your boating activity, some are lucky to get a 3 year life. You have low water pressure now, I suspect an overtemp condition will be next.

I'm not certain where the water temp sensor is, but if you purchased a manual from Mercruiser, it would show you where it is.
 
PMC
Had same problem on my 07 280 and got no info from anyone I asked. So started digging around and found it. It's located on the power steering cooler behind the engines, looking at the engine it's on the left it has a three wire plug on it. I've replaced two of them so far one on the port and one on the starboard. Here the part #MM-881879010 they cost 89.92 from ishopmarine.com located on long island. Hope this helps you out. The socket size to remove it is a one inch deep. Good luck.

Fourd's II
2007 280 4.3's Alphas
 
Back of engine on oil cooler. Pain to get to. Be careful not to bend the oil cooler when removing. Most of the times they go bad when the boat sits idle for a period of time in salt water. The salt crystallizes at the tip of the sensor. They are about $90 to replace.
 
Four'Ds & GMAN1
This is exactly what I was looking for - Thanks!!

I'll be at the boat tonight for a better look - I did see some plugs and wires in the area of the cooler - it looks very tight in the 280 - I'll be leaving some skin on this one.


Chris Dauth - that particular PDF does not have any links to other pages. I was able to search based and find the 5.7 manual (17cov2r2.pdf). I do see what you describe. I'm going to just buy that one from my supplier. Looks like lots of great info.


Again - Thanks for everybody's input - very much appreciated.:thumbsup:
 
Yeh Jeff -the impellers were changed over the winter - and NOT run dry. I ran the boat steady for several hours before (and after) the fault error. The engine temp was stable while running at a Zero PSI.


thanks for the post.
 
The parts are ordered and will be in tomorrow - I won't have the Manual until next week :wow:

Assessing the job - I see it to be very difficult!! The sensor is the Port Engine - smack up against the water heater.

I was trying to view the sensor with a mirror only to find I have a lot to disassemble.

Oddly enough the fault is no-longer a problem - I ran the engines today and all is OK. I anticipate the same fault in some time, but I may have a brief break.

Has anybody attempted this repair? Do I need to break down the oil cooler system?
 
if you are looking for the water pressure sensor it isn't against the water heater down low. That is the oils pressure sensor. they look the same but different part number by 1 number. If you are in the bilge looking at the port motor behind the distributor cap there is a black metal cooler with 2 3/8 hoses coming out of it. It is hard to see. If you grab that cooler which is the power steering cooler there will be a sensor screwed into that cooler closer to the inside of the boat. sometimed searay tie straps the power steering hoses to the cooler because the port power steering isn't being used, which makes it hard to remove the water pressure sensor.
 
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