Water Pressure Gauge Reading, long read.

[C Shiner]

Greeting,



I have a 2010 Z7 with a 150 opti, from new the water pressure gauge only registered 10 PSI max; during delivery the dealer said some read high and some read low, that

 

[Scott Hammer TOXIC]

Incoming pressure has nothing to do with the gauge. The gauge registers internal water pressure via the water pump/impeller. That is where your pressure reading comes from. the pickup and associated tubes only supply water, the impeller produces the pressure. As a matter of fact it is not recommended to put too much pressure through the flush port (garden hose connection) and to only let engine idle. On the muffs you will notice the pressure increase with the rpms....point being, don't confuse delivery pressure with engine pressure, they are not the same.



TOXIC

 

[C Shiner]

Not sure I agree with you on the water pressure. The pressure line is located in a coolant galley between the heads; the incoming water pressure from the garden hose will pressurize the water passages in the motor, which is why I saw the typical 10 PSI on the gauge, when on the garden hose. I didn

 

[Bob Bourget2]

I would recommend having the dealer hook it up to the CDS and verify engine operating PSI. It sounds as though there is a cooling system malfunction...whether a stuck therm {or therms}, or poppet. It can be picked up with the computer.

 

[C Shiner]

Thanks Bob, that was my thought too, off to the dealer I go. Will report back on findings.



Does Mercury offer high pressure low volume and low pressure high volume pump assemblies for the 150 opti depending on useage / type?

 

[Bob Bourget2]

There is only one pump available, and it is the high pressure, low volume style found on all 2.5 litre V-6 mercs.....

 

[C Shiner]

So I call the selling dealer and he tells me the computer scanner can

 

[Bob Bourget2]

-1] Water pressure at idle is about 4-7 psi, WOT 11-14.

-2] "Bad" therms....over OR under temp.

-3] Poppet stuck closed...too much positive pressure, stuck open...too little.

-4] Water pump issues GENERALLY result in under pressure....

-5] There could be a slight overlap with poppet and pump isses....together.

OH....and the CDS can most certainly read out water pressure, as well as Smartcraft gauges.

 

[C Shiner]

So I messed around with the water pressure line (to the gauge) a bit more to make sure there were no kinks. Part of the process included blowing 35 PSI through the lines with the gauge disconnected in both directions. Well I went to the lake this AM and to my surprise I now see 4 lbs at idle, 6 lbs at 1300 rpm and 15 lbs WOT!



So