Adding Gauges to your vehicle is a simple way to get access to REAL information about what is going on with your truck. Your vehicle already comes with a few gauges such as a speedometer, a tachometer, a fuel level gauge and a coolant temperature gauge. So why add more or why replace what you have? There are a few simple reasons.
The first is that some important gauges have been left off as a concession to looks. They are oil pressure and a voltmeter. The oil pressure guage is probably the single most important gauge in the instrument cluster. Lack of sufficient oil pressure means your engine is going to stop operating very soon, and the damage will be permanent. A voltmeter gauge is imporant in monitoring your vehicle electrical system and will alert you to the fact that either your battery is failing or your alternator is failing. Particuarly important if you have a lot of electrical accessories or you are running a winch.
Second, the gauges installed in most vehicles are very inaccurate. The coolant temperature gauge is very susceptible to failure and not always total failure. It may register low, or high, or register both low and high in different circumstances. In my case, it only registered from low to normal. It read normal even as my coolant temperature was skyrocketing and I had seveal boil-overs while the gauge said everything was perfectly normal. Clearly an improvement was necessary over stock.
Ok, so now that we know why to add gauges, which ones should we add? Well, that is somewhat dependent on the driver/owner, but there are a few minimums that should be followed. Obsiously you need a speedometer, and a tachometer is nice, but really not that necessary on an automatic transmission vehicle. Oil pressure is a critical function and should be monitored. Having an accurate coolant temperature gauge will help you save your engine. And a voltmeter can tell you if your about to be left in the dark... literally. Some have replaced their fuel level gauges feeling the stock one to be too inaccurate. Others have installed air/fuel ratio guages to keep an eye on economy. These should be considered secondary though.
Ok, the biggie, whats the difference between electrical and mechanical? Well, they both have Mechanical Oil Pressure Gaige their merits. They both do the same thing in different ways. They both read either temperature or pressure (in most cases) and then cause a reading to be made at the gauge. The electrical ones do this by electrical impulse, while the Electrical oil pressure gaugemechanical ones do it by mechanical means. Both can be just as reliable, and both can be just as accurate. The problem comes in with making the choice of installing the rather large electrical senders in the engine compartment, or plumbing hot, and dirty liquids into the passenger compartment. It is somewhat easier to run wires through a firewall/bulkhead to a gauge than it is to plumb in tubing. However, plumbing tends to be much more durable over the long haul than wiring, particularly where harsh conditions can cause corrosion on electrical connections. When electrical connections begin to fail, they can give erratic or erroneous readings and you are no better off with your expensive replacement gauges than your stock ones. When mechanical gauge fittings fail, they leak fluid, sometimes inside the passenger compartment. To a large extent, mechanical gauges seem to be superior if you have tolerance for a possible connection failure in the passenger compartment.
I chose mechanical gauges for my application even though most people chose electrical. I was confident in my ability to plumb quality connections and I have a good tolerance for possible failure. I also liked the fact that the mechanical gauges have 270 degrees of movement to read their range of temperature or pressure, while the electrical ones tend to only have 60-90 degrees of movement. This makes the mechanical gauges much easier to read at a glance.
So who makes good gauges? Well, there are two kinds of gauges. Those which are calibrated, and those which are not. Calibrated gauges are guaranteed to be accurate when they leave the Gaffrig white face gauges factory, and you pay for that accuracy. Non calibrated gauges carry no such guarantee and are much cheaper. I have never seen an automobile or boat application that used calibrated gauges. Autometer UltraLite Water Temp GaugeThe jolts and bumps simply destroy the fine calibration of the more expensive units and then you either have to pay to have them re-calibrated, or you live with the fact that your previously expensive calibrated gauge is now no more accurate than a much cheaper non-calibrated gauge. You pay your money, and you take your choice. And in truth, are you really going to care that your truck boils over at 249 on one gauge and 252 on another? Or is it more important that seeing your temperature climb from a normal 195 degrees to 250 degrees? So when looking at Non-calibrated gauges there are a few large manufacturers including VDO, Gaffrig, Autometer, Sumpro Water Temperature GaugeSunpro, and others. I invite you to spend some time looking around at what people who make their living reading gauges use. I watched road races, truck races, boat races, etc. In nearly every instance, those people were using Autometer gauges, except for the boaters, who were using Gaffrig. Closer inspection told me why.
Autometer gauges come in several sizes, and have VERY large and easy to read numbers. They VDO Pro Cockpit Water Temp Gaige offer electrical or mechanical gauges. They are built to last. And they offer every possible accessory or implement to install their gauges in one place. And to sweeten the pot, they are quite reasonably priced. The Gaffrig gauges seem very good, but are almost entirely electrical which made them unsuitable for my needs. The VDO gauges are almost all electrical as well, and they have very small numbers and writing which makes them hard to read at a glance. Sun really wasn't in the picture as they usually offer products that aren't up to the rigors the others are. Yet others specialize in digital gauges which I don't recommend as they are VERY difficult to read and comprehend in a hurry.
Recently I installed an Autometer oil pressure gauge and an Autometer water temperature gauge from Jegs High Performance shop. I will offer information on each of those installs so that others may benefit from the experience.