Edward

You'll forgive me but all this "the guage is not to be trusted" is nonsense. Sure you should "ultimately" rely on the dipstick at oil changes or when adding oil, but there is no reason why one cannot trust the guage for all that time inbetween oil changes. Newbies are forgiven, but for anyone who has owned the car for a time, it's all very straightforward:

The car must be HOT, with temp at 8-9 oclock; any cooler than that and the level will show low since hotter oil will have expanded. So with engine HOT, idling for about 30seconds or so, and on level ground, the gauge will read pretty darn accurately, or so it has in my car since I bought it. It is so easy, you can monitor the level at stoplights ...a heck of a lot easier than trying to read the stupid-long stick with lame-o twisty thingy (technical term) at the end.

As a data point, I've found that 60-75% on the dip-stick corresponds to 60-75% on the gauge (again, with the engine hot!), which is where I like to keep it. And yes, you CAN overflow the oil tank. Lots of warnings on this, but typically happens when the oil level is topped off at a lower temp, then you go and get the car stinking hot and it expands ...out the filler cap. This has never happend to me personally, but I'd mind others' advice on this as it HAS happened, albeit typically on the track where temps are typically elevated.

Sorry to sound like a curmudgeon on this, but c'mon, the guage ain't the POS that many make it out to be ...and if it is, then it's broken. Peace all.


Edward

Terry Adams

My gauge has corresponded perfectly with my dipstick for the last 120K miles. You could set an atomic clock by it.

I do wonder why they made the dipstick the same color as the clean oil I am reading on it. Why not flat black?

BIG-BRO

This discussion reminds me of a project I worked on as summer engineering student at General Motors regarding fuel gauges - same principle: float moves variable resistor and gauge displays based on resistance. We took a sample of above 12 floats, 12 gauges, 12 wiring harnesses, and 12 tanks and tested the whole matrix of combinations (yes, they can subject summer students to this type of repetitive work...). When we charted out how much the gauge reading could vary based on the tolerances of each part it was a huge swing - like a quarter of the gauge. Bear in mind all the tolerances - plus/minus a few percent on each component multiplies when you combine them. So, yes it is a case of getting to know your car.

ventoGT

My gauge must have issues because the only time that it ever reads is when the oil is totally full....even then it doesn't read even 3/4 of the way up. Had a stealership oil change a month ago, got the car nice and hot on a 30 minute drive after picking it up, let it idle for 5 minutes to make sure the oil went to the cooler....checked the dipstick--full. Looked at the gauge--1/2 or less. Once I get to mid way down the dipstick [which is where most people apparently like to run their oil level], the gauge is pegged on Red and I keep checking the damned thing every 100 miles or so just to make sure I'm not going crazy.

2000 miles after my change, I was about half a quart low [oil on the bottom of the twisty but not much farther up]. Added a half quart, gauge didn't move a centimeter [and yes, I filled VERY slowly so as not to dump it out all over the place].

I may get the gauge looked at when I take it for the next change in a few hundred miles just for peace of mind, but basically I have gotten into the habit of trusting only the dipstick, so the gauge isn't reliable on my car...

Just my $.02

Edward

Hi Cole,

Indeed, the guage does sound like it's reading consistently low on your car. If you're accustomed to it, you can leave aloneit since you already know how it reads. Personally, I'd have it fixed or checked so that 50-75% on the dipstick at least resgisters on your guage. Perhaps someone can post how to check the float? ...prob just checking resistance across the leads...?

Edward

Luis A.

Cole and Edward,

As I indicated on my post, just take the float off (easy job) and grab the 'float' while looking at the gauge and observe the correlation. Mine was linear.

993inNC

Edward......exactly my point. they are very easy to read if you use the car enough. And for Vento, these gauges are acuated by a reostat just like your fuel level sending unit, if its bad, the gauge won't read correctly......but they are very accurate in general.....at least as much as your fuel is

blackcat

did a quick search but didn't find anything... how far down do I have to be before the oil warning light comes on?

I have to admit I haven't for the info yet - I'd check but my wife has the car