Best Multimeters for Diesel Mechanics



Any good diesel tech mechanic will tell you that working on garage and industrial shop floors on heavy-duty engines and equipment is a tough operating environment and likewise require an equally rugged and robust multimeter. This is not something you buy every day, therefore, there can be no compromise in this regard.

Apart from a versatile set of functions, accuracy and ease of operation are important criteria, the multimeter should be able to withstand the heavier workload and last a long long time too.

After extensive research, our experts have short-listed the three best multimeters that a professional diesel tech mechanic will need.

All things considered, Fluke multimeters set the benchmark. You can count on their accuracy, reliability, ease of operation, build quality, user experiences, popularity and warranty.

Accordingly our top picks are:

Importantly, they are manufactured in the US.

Table of Contents

Comparison Table

Here is a quick summary of the main differences in features and specifications associated with the three products:

Parameters Fluke 87VFluke 88VFluke 223
Voltages AC/DC1000 Volts in both AC and DC

Accuracy in DC +/- 0.05% + 1 count and in AC +/- 0.7% + 2 counts.
1000 Volts in both AC and DC

Accuracy in DC is +/- 0.1 to 1 count and in AC is +/- 1% + 4 counts.
Range 0.1 mV to 1000 Volts in AC and DC

Accuracy in DC is 0.25% + counts Accuracy in AC is 1.0% + 3 counts.
Max Resistance Levels50 MΩ
+/- 0.2% + 1 count
50 MΩ
+/- 0.4% to 2 counts
0.1 Ohm to 40 MΩ
+/- 1.5% to 2 counts
Current AC/DC in Amps10A (20 Amps for 30 seconds) +/- 0.2% + 2 counts in DC and +/- 1% +2 counts. in AC true RMS

Accuracy +/- 0.7% to 2 counts in AC and 0.05% +/- 1 count in DC
Range from 0mA to 6000 mA in AC and from 0 mA to 10 A in DC

Accuracy +/- 1% to 4 counts in AC and +/- 0.1% to 1 count in DC
10A (20A for 30 secs) Range in AC and DC Current is 0.1 mA to 10 A

Accuracy in DC is 1.0% to 3 counts. Accuracy in AC is 1.5% + 3 counts
Battery Type Safety Standards9 V battery pre-installed

CAT III 1000V, UL, CSA, TUV, and VDE listed and CAT IV 600V
9V battery plus a Power cord

CAT III for 1000V and CAT IV for 600V IEC over voltage CAT III
5 AA batteries

Safety: CAT III for 1000V and CAT IV for 600V
TemperaturesOperating Temps. Between -20oC to 55oC Operating Temps: -20oC to 55oC Operating Temps: -10oC to +50oC
Size and Weight2.06 x 3.86 x 7.93 inches

Weight: 0.783 pounds without holster and 1.376 pounds with the holster
2.06 x 3.86 x 7.93 inches

Weight: 3 pounds
3.66 x 2.09 x 0.76 inches

Weight: 1.33 pounds
Top FeaturesLifetime Warranty. Display 6000 counts in 4 secs and 19,999 counts in high-resolution modeLifetime Warranty. Display up to 6000 counts 19,999 at 40 times a second in high resolution modeThree-year Warranty

The Reliable Fluke 87V

When you need a quick reliable and accurate solution to the most complex problems, few can match the 87V. This instrument comes with the all-important NIST-Traceable Calibration with Data. This certifies that the multimeter is tested to the high standards set by the respective industry.

Fluke rates the 87V as their most rugged multimeter ever built by them! It can withstand extreme hot and cold temperatures, wet and dirty working conditions, up a ladder or down a hole. You name it and the 87V performs admirably in every situation. It works where others fail!

Top Features

The 87V delivers a true RMS reading in cases where the displayed voltage is not in a pure sine wave reading. It is specifically designed to work under hard conditions like loud and high energy environments, including in industries situated at high altitudes.

The 87V is strong enough to withstand a fall from 4 meters or 13 feet, besides being dust resistant and waterproof.

It is equipped with a two-level back light for better visibility in dark places. Also, included is an analog bar graph, to detect unstable signals with a relative reference guide and an input alert. Additionally, there is a Touch Hold function to display the reading even after the probes are removed.

Whenever the speed of a motor needs to be controlled, the VFD (Variable Frequency Drive) provides the required assistance.

The 87V includes a Peak Capture function when used in systems that generate high frequencies and reduce the loud sound that emanates from large drives,.with a specially designed shielding system in place.

The holster provided with the 87V can hold a test probe for easier storing, besides, this holster is detachable. There is an optional magnetic hanger that facilitates hands-free operations and increases its friendliness further.


  • The 9V battery can be replaced easily without disturbing the calibration seal.
  • Displays up to 19,999 counts in high-resolution mode.
  • Very high accuracy across most parameters.
  • Lifetime Warranty.


  • Nothing significant

User Feedback

From the global ratings, 95% voted the Fluke 87V for its all-around performance and accuracy. It is essential to examine what the other 5% had to say.

There is the occasional defective unit. In one case for instance, the COM jack was displaying lower readings than the hazardous ones one customer was working on. However depending on return policy and when the defect manifests, product can always be returned to the seller.

One customer thought it was a very bulky multimeter with a dim light and a low beeping sound. Another bit of customer feedback is that a plastic shield would be necessary to protect the multimeter effectively.

There is a feeling that the Fluke 87V is a very versatile multimeter and makes a lot more sense to buy than other products. The product is also used by a wind energy technician for dozens of electrical tests.

Read more reviews on Amazon

The Highly Rated Fluke 88V

The 88V has been specially designed for garage/industrial shop floors. Besides, judging by the high standards of Fluke, the 88V is their most resilient multimeter.

The range of functions and the corresponding accuracy offered is commendable and this is probably one of the most versatile multimeters available.

Top Features

Apart from the standard measurements that many multimeters offer, like AC/DC Voltages and Currents, Resistance, Capacitance, the 88V performs admirably when dealing with problems with fuel injection systems. The pulse-width function is accurate to the millisecond.

Whenever the need arises to deal with unstable signals, the bar graph offers good support. An important feature is the Min/Max/Average function that automatically records all the voltage variations.

In addition, Diode testing is simplified with its accurate pulse-width measurements. The Current for 10A and 20A can be measured continuously for 30 seconds and permits a good test for continuity. Also offering a range of up to 1000 AC and DC Volts [DC accuracy is 0.1%].

The other equally critical tests performed by the 88V include the frequency measurement up to 200 kHz and the duty cycle percentage.

With a couple of optional attachments, its versatility is enhanced to read the Temperature and the RPM with the Inductive Pickup.


  • Two-level bright back lights for greater visibility
  • High Safety Standards are maintained
  • Can withstand voltage spikes of 8000 volts
  • It can operate under the most demanding conditions including high energy environments found while working on Hybrid vehicles
  • Display up to 19,999 counts


  • Nothing significant

User Feedback

With a 95% positive rating, this is a very popular instrument with many satisfied and happy buyers.

As with every product it sometimes makes good sense to evaluate the negative ones as there may be something worthwhile there.

One user felt that the auto-range function is not as accurate as some of the other Flukes he has used.

Another still preferred to use the older Fluke 88, not this newer version 88V. The main difference is that the 88V does not provide a true RMS reading and is less accurate. Besides, it switches to the DC mode when used on Current ranges.

One of the buyers was disappointed that no other leads can be used with the Fluke 88V and wished he had bought the entire Fluke 88 automotive kit with it.

A user also suggested that the 88V was the best for measuring fuel system pulse width tests. A diesel specialist thinks that the 88V is the most powerful multimeter offered by Fluke to date.

Read more reviews on Amazon

The Most Flexible Fluke 233

The 233 lets you reach places that are not very accessible or situated in a hazardous environment. As Fluke puts it “you can be in two places at the same time.”

The removable display is a special design and differentiates the 233 from the other multimeters.

Top Features

The removable display is magnetic and can be attached to another suitable surface for better visibility. The detachable display can be carried to a distance of 33 feet without using extra power. The built-in thermometer reads temperatures, excluding the need for an additional device.

The 233 offers a long battery life of 400 hours. The true RMS feature provides accurate readings for non-linear signals.

It provides accurate 1000 AC/DC voltage readings and reliably measures 10A and up to 30 seconds for 20A. Continuity and Diode testing are important features that are included in the 233.


  • The remote display is rugged, reliable and provides good safety.
  • Low power wireless technology is used in the remote backlight display.
  • The radio transmitter automatically turns off when the display is connected to the multimeter.
  • The 233 comes with an alligator clip, a sturdy test lead, a 80BK-A Temperature Probe, a CD-ROM and a Users Manual.


  • The batteries drain out when not in use
  • Response time is not very efficient

User Feedback from Amazon

From a worldwide user base, 92% view the 233 favorably. Let’s examine some of the more critical comments.

One of the strong critics cited that the leaked batteries corrode other parts of the multimeter. Yet another stated that the 233 was a great multimeter, except for one flaw: it uses 5 AA batteries instead of an even number. There was also a feeling that a soft carrying case is essential.

On the positive side, an experienced user of the 87/88V, mentioned his next upgrade would be a 233. In his opinion, a typical diesel engine needs true RMS AC, Resistance, DC voltage and amp measurements in higher ranges, (not so much in the lower milli or micro). Besides, it must have manual and auto-ranging capabilities. Also, the removable magnetic display is a huge plus.

Read more reviews on Amazon


From these specifications, it is evident that Fluke multimeters are amongst the best in their respective categories. It is a given that any good Diesel/Tech Mechanic cannot do without. The Fluke 88V portrays a slight edge over the 87V in terms of accuracy and resilience, whereas, the 87V has an advantage with its ability to provide True RMS reading, which the 88V cannot do. The 233 has a unique advantage with its detachable magnetic display screen though it may lose out a little on other counts.

Final Words

Fluke multimeters are considered by many as the last word in accuracy, versatility, build quality and user-friendliness. They are used by some manufacturers to re-calibrate their multimeters, using Fluke as the benchmark. All the three specified here are competent in their own right.

Fluke 87V

Choose the right one for your specific requirement!


Photo by Garett Mizunaka on Unsplash