Gauges Misread Randomly

[heyitsrama]

I’ve noticed that the Engine Coolant temp and the oil pressure read high at random intervals. If I come to a stop/idle the oil pressure can be up to 45psi, when driving around 35mph it can be up to 55mph. The water temp goes from being in the middle, to sitting on the right of the gauge.

originally I thought the issue was a problem somewhere in the cooling system, or that the oil system had a blockage. (Briefly inspected to make sure it was not the source of problem)

I was thinking perhaps this is a grounding issue, I’ve noticed that the voltmeter kinda waves and flutters 12v-13v. Has anyone seen an issue like this?

Ive started tracking the car more, and really want to get it stable so I don’t have to be too worried about it on the track.

[grannyknot]

The oil pressure will vary depending on where you are in the RPM range although our oil pressure gauges don't respond very quickly.  That water temp reading that is pegged to the right is not good, could be the fault of the gauge but could also be an air pocket around the temp sender.  You need to burp the coolant system to eliminate that possibility. Voltmeters will also vary in the reading depending on the demands but it should be reading about 14 most of the time.

[Mark Maras]

 I'd also verify the coolant temperature with a thermometer to find out if the gauge is wrong.

[Dave WM]

something odd with high coolant temps and high oil pressure, generally speaking those have an inverse relationship. (cold engine high oil pressure, hot engine low oil pressure for the same RPM) Middle gauge reading on oil at idle on startup is pretty normal but not once the engine warms up. also what is the idle rpm, 800 to 1000 has a notable effect on oil pressure.

typical oil pressure at idle with fully warmed up engine would be more like 15-20 psi (gauge indication about 1/8-1/4). The oil pressure gauge is not well known to be accurate, so any pressure is prob ok. you can get large changes in oil pressure just by changing the sending unit and or cleaning and tightening the connection to it.

 

Edited August 20, 2020 by Dave WM

[Dave WM]

a few other thought, you may want to look to pull the oil fill cap off while running, idle up to see how much oil is being slung around the camshaft if you have concerns about something plugged up. If you have a spray bar its prob a good idea to check it for flow, I removed mine, spray clean with brakecleen, reinstalled with new gaskets, verified oil flow by removing valve cover and cranking the engine ign off, after several seconds at crank speed you should see oil dribbling out of all the hole in the spray bar at about the same rate. I suppose if you have a internal lubed cam shaft the same test could be done, just to confirm all is well. I suppose if all was not well you would see it in cam lobe wear.

 

[dutchzcarguy]

20 hours ago, Dave WM said:

something plugged up

HAhaha.. reminds me of a neighbour.. (he could not hit a nail with a hammer )  He askt me to look at his fresh installed battery (By HIM!) in his caravan....  He had the isolating caps still ON the poles and had to open the clamps a whole lot to get them on... he askt me why it did'nt work... wow man... then it's terribly difficult to keep the face straight!