My oil and temp gauge read the same?
I’m gonna try to detail this as much as possible, it is on a 92 F250 460 XLT (didn’t give me the option to select 9th gen). So the deal is that my temp gauge and oil gauge in the instrument cluster read the same usually fairly high, above or at the L in “Normal”. This is when the engine warms up, so the coolant gauge is somewhat correct in that when it is cold it tells you so. But the issue remains that it seems I have high oil pressure and a high operating temperature. It does fluctuate up if accessories are used, such as heat or ac, headlights, etc. The voltage gauge also reads low, not extravagantly, but usually right around the N on “normal”. So to the specifics, i am running 10w-30 oil as is recommended, the water pump was recently replaced and filled properly, the thermostat was recently replaced, i have checked grounds to the negative battery terminal (hoping thats all it was) and cleaned them, the fan clutch was also recently replaced, and nothing leaks worth mentioning. I’m kind of at a loss, i almost wonder if its the alternator due to this truck being fairly new to me and the previous owner installing one that i don’t believe to be ‘for this truck’, it doesn’t look to belong and connections were MADE not reconnected for its function. I wonder if its not supplying efficient power yet the battery is 3ish years old so if it wasn’t i’d think that i’d have more problems starting or running accessories. I did test the running voltage which was fairly low in my opinion 13.4V. I can’t imagine the problem being all three gauges at once despite its age. I keep forgetting tid bits so i apologise for the random adds of information like this one, i doubt its a huge problem but it does have an aftermarket oil cooler, i’d hope that doesnt cause my gauge readings due to the sensors being in different spots, but i just figure its worth the mention for thoroughness. Thank you for reading and anything helps!
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Hi @cpwilliz ,
Where did you test the voltage with the engine running?
With the engine running the voltage across the battery terminals should be in the range 13.8-14.5 VDC. Anything less than 13.8VDC and you are not charging the battery correctly.
It may be that the alternator is not supplying enough voltage under load or perhaps the regulator ((which may or may not be in the alternator - I don't know your vehicle) is not maintaining the correct voltage under load.
Not sure as to why the gauges would read high if the voltage were low though.
Suggest that you get the alternator output checked under load (turn on high beam headlights and a few other "high" power items e.g. aircon, hazard lights, radio and wipers etc all at once and check what happens to the voltage level) to make sure that it is still near the correct value - you may have to increase the engine rpm to help it a bit if it reads a bit low at idle) and then once satisfied that it is OK and the problem still exists to go one step at a time from there.
Check the voltage at the fuse panel for the instrument cluster and also at the ECM if that is where the gauge signals come from if they're not a direct feed from the sensors that is.
Just some thoughts
jayeff 의
Battery terminal voltage is reading 13.5 standing, under load about 13, even with raised engine speed. Just concerned with the charging system over charging the battery and causing some spillage onto the radiator support. My guess was maybe low voltage was making it harder for the truck to supply power. Also, voltage at fuse panel is spot on 12V, with engine off.
Cwilliz 의
Hi @cpwilliz ,
Still a concern at 13.5V
Perhaps you could try another meter just to verfiy that the meter is OK.
13.8VDC is the charging voltage required to ensure that all the cells in a lead acid battery are properly charged and it will therefore perform correctly when needed.
Overcharging usually only occurs when the voltage is >14.5VDC.
Is the electrolyte level in the cells dropping, presuming that it is not a maintenance free battery so that you can check?
Spillage is unusual as when overcharging occurs, boiling action happens and the water (hydrogen) in the electrolyte actually "evaporates" and is vented from the battery. That is why it is dangerous to charge (overcharge if attempting to speed up the process) lead acid batteries in enclosed spaces as the gases given off can explode if exposed to a naked flame.
I would still get the alternator/regulator checked as the voltage output, whilst OK is not correct and the fluctuations you're observing may be due to the alternator output not being consistent.
It may be better to start from a known good condition i.e. alternator/regulator output is good as it has been tested and then go on from there.
As for the gauges, try disconnecting a sensor lead at the sensor itself, either the coolant sensor (make sure that you get the correct one if there are two - one for the gauge and one for the ECM) or the oil sensor (again check in case there are two) and check if the appropriate gauge stops registering. Just wondering if there may be a connection between the two leads somewhere (perhaps back in a control module if they don't feed directly to the gauges) and that is why they're both reading the same and behaving as though in concert.
jayeff 의