Engines running water pressure at different PSI

[BritLady]

Our stbd engine's water pressure is running at 13.08 psi and our port side at 19.00 psi at about 2,000 rpm (it's supposed to be 15.00 psi according to the manual). Any thoughts anyone on why that may be? Could it be the radiator cap.....time for new perhaps? It's recently started this and all the other gauges are normal. Thanks for any insight

 

[kaz911]

Our stbd engine's water pressure is running at 13.08 psi and our port side at 19.00 psi at about 2,000 rpm (think it's supposed to be 15.00 psi according to the manual). Any thoughts anyone on why that may be? Could it be the radiator cap.....time for new perhaps? Thanks for any insight

First thing to check is the water pressure sensors - switch them around
2nd thing to check is impellers in the water pump. You should really exchange them every 12-18 months
3rd thing is the heat exchanger - is it full of gunk?

And then Merc Water pumps are known to fail - so open the hatch and listen at the water pump for slight "clicking" sound - if you hear that - the bearing might be ready to give up on the pump. The more tropical the water - the faster the pumps bearings loose their grip. You can recondition it for about $130-$140 in parts vs. $600 for a new one.

 

[BritLady]

First thing to check is the water pressure sensors - switch them around
2nd thing to check is impellers in the water pump. You should really exchange them every 12-18 months
3rd thing is the heat exchanger - is it full of gunk?

And then Merc Water pumps are known to fail - so open the hatch and listen at the water pump for slight "clicking" sound - if you hear that - the bearing might be ready to give up on the pump. The more tropical the water - the faster the pumps bearings loose their grip. You can recondition it for about $130-$140 in parts vs. $600 for a new one.

Thanks kaz911, will check out next time we visit the boat, the impellers were done not so long ago, so maybe the other items you mention. Thanks again!

 

[matthewmiller01]

Where did you find the expected numbers for your engines? I need that info for 5.0l MPIs and I don't remember seeing it in my manuals. I'll have to go back and check.

 

[BritLady]

Where did you find the expected numbers for your engines? I need that info for 5.0l MPIs and I don't remember seeing it in my manuals. I'll have to go back and check.

In our electronic manual it's in the Cooling System section wich happens to be Section 6A in ours then it's under Pressure Cap Rating specifications. Hope that helps

 

[matthewmiller01]

In our electronic manual it's in the Cooling System section wich happens to be Section 6A in ours then it's under Pressure Cap Rating specifications. Hope that helps

BritLady: You have closed cooling, huh? I have no cap (open cooling).

 

[BritLady]

BritLady: You have closed cooling, huh? I have no cap (open cooling).

Yes, ours is closed cooled and we noticed last week-end it actually states 15 psi on the cap! Wish we'd have noticed that before, would have saved a lot of manual searching

 

[kaz911]

Yes, ours is closed cooled and we noticed last week-end it actually states 15 psi on the cap! Wish we'd have noticed that before, would have saved a lot of manual searching

Remember the CAP is for the coolant - not the water.... You have 2 pumps - a circulation pump for coolant - and water pump for raw water. The Raw water pump (looking aft) is at the lower left - the coolant circulation pump is about in the middle.

 

[BritLady]

Remember the CAP is for the coolant - not the water.... You have 2 pumps - a circulation pump for coolant - and water pump for raw water. The Raw water pump (looking aft) is at the lower left - the coolant circulation pump is about in the middle.

Yes thanks, we believe we have a blockage in the raw water system which we need to unblock when we have the time......always something

 

[kaz911]

Yes - always something to do

Here is what I wrote in another thread about flushing heat exchangers:

De-scaling heat exchangers works well if you are in a place with lots of barnacles and other marine growth. But you can do it yourself. A big bucket - and Acid safe pump - a few hoses and maybe some Triton Marine/Rydlyme or Barnacle Buster de scalers - and you are ready to go.

Rydlyme has a 8 gallon pump + bucket + hose system - that runs on 12 or 115 v - for about $600. You can make one yourself for less but not much less after you get all the connection parts ets.

I have just done my A/C - and next project is my heat exchangers on my 350Mag Seacores.

It did wonders for my A/C back to full push. And a lot of crap came out of the AC hoses (about 1 1/2 kg...) Next up are my heat exchangers.