CRD Glow Plugs – 5 Volt or 7 Volt?

If your Jeep Liberty CRD needs replacement glow plugs, you might be confused by the different options, including choosing 5 volt or 7 volt editions.  This guide will walk you through making the right choice.

About the Factory Plugs

The factory plugs on the Jeep CRD were a new-generation ceramic glow plug made by Bosch.  Ceramic plugs are able to get hotter than traditional steel plugs, making cold starts quicker and less smokey.  Unfortunately, the first generation of Bosch 7V ceramic plugs were prone breaking off and falling into the engine.

5V Recall

Shortly after Jeep ended CRD sales in 2006 a “light recall” was announced to address the ceramic plug issue.  We call this a light recall because customers were not specifically mailed and notified to bring their Jeep in for service, however, if the Jeep was at a dealership the tech could be prompted to perform the repair.  This means that this recall was performed on some, but not all CRDs.

The repair consisted of removing the 7V ceramic plugs and replacing them with a 5V steel plug, then replacing the glow plug control unit and reprogramming the ECU (engine computer) for new 5v programming.

Since the new 5v plugs were made of steel they could not get as hot as the ceramic plugs, and unfortunately cold-starting performance suffered.  As the temperature dropped owners found they needed to use the block heater more often to get their Jeeps started.

Determining Your Version

Officially speaking, you should replace your glow plugs with the same version that the car is programmed for.  The easiest way to determine your glow plug version is to take out a glow plug.  The voltage rating will be stamped into the glow plug shoulder.2858_crd5vglowplug2

If your car is chip-tuned (or you are going to get it tuned) your tuner can also tell you which programming you have.

[UPDATE] Running 5V at 7V Programming

As we mentioned above, the 5V steel plugs have not been as effective as the ceramics were at sub-freezing temperatures.  Traditionally it was thought that running the 5V plugs at the higher 7V programming  would cause the 5v plugs to burn out.

A few members on the LostJeeps CRD forum (if you haven’t joined yet, do so!) decided to purposefully run the 5v plugs on their 7v programmed CRDs to see what would happen – how quickly would they burn out, and would it improve starting?

First impressions were dramatically improved starting, and, now that over a year has gone by, none of the test plugs have burned out yet.  It is still a gamble, but, it seems that over-driving the 5-volt plugs has worked for these members.

What did you do?

We’ve taken a few polls and opened a few threads on this topic in the forums, but, we’d love to hear from you here, too.

Related Products

Liberty CRD Glow Plug [Bosch Steel]
Liberty CRD Glow Plug [Etecno]
Liberty CRD Glow Plug and Harness Kit

  1. Michael Jardine / FB October 17, 2017 at 2:40 pm

    I have two of the beasties. One just got changed to 5V on 7V platform. We are just coming into the Canadian winter so time will tell. The second CRD will be changed to the 5V plugs during the next timing belt change, unless I get a failure before. Having one of each I will be able to compare performance during the winter, side by side.


  2. Hi, the name is Alan and my CRD was the first sold in the U.S. (verifiable). It has been sitting waiting for me to replace the timing belt. I am now in a cold climate ,Winslow, up on IH 40. I have never to this date replaced my glow plugs but bought the last two a dealer in Austin had. They are the originals. When the time comes I will consider all the posts and my options but with life changes I’ll probably choose the 7 v. route just because I already have two brand new ones and from what I heard they can be mingled with the new 7v.’s???? All for now thanks, Alan


  3. My 2006 Liberty (now 305 000 km) was starting great down to -30 C until January 2017. Suddenly, the remote start could not start it below 0 C, and it progressively got harder to start directly with the key. Just before I tore the engine apart for a rebuild, one of the four glow plugs popped a code as failed. I replaced the stock 7 volt glowplugs with etechno 7 volt glowplugs and a new controller. Also replaced the turbo, rockers, head gasket, fan clutch, timing belt, water pump, alternator pulley, boost hoses, transmission cooler hoses, AC seals, radiator, EGR exhaust feeder tube, EGR (disabled afterwards as it caused Jeep to stall when putting in drive or reverse), ALL of the sensors and some of the wire harness. Discovered the 3rd party remote start severed camshaft sensor wire which had led to intermittent no start issues until I repaired the wire directly to the ECM and tore out the remote start system. Ran great through summer 2018, but still starts hard below 0 C, and absolutely will not start below -10 C without using starter fluid or block heater. All of the new glowplugs and wiring passed multimeter testing and get hot enough to melt electrical tape, but do not glow like every other glowplug I have ever used.

    Not sure what to do. Should I switch to 5 volt glowplugs with 7 volt programming? Would rather not spend more money on glowplugs when I already have new ones. Not to mention three of the old glowplugs were working just fine out of the engine, but were not getting hot enough connected to the old and new controller. Could the ECM be glitched out?


  4. E Techno link above doesnt work ….I have 7v E-Technos and have had no problems starting at -5 so far . I saw an owner stating he was throwing a PO234 code that was fixed with a 7v glowplug reflash but nobody knows why this worked or caused this code and limp mode , perhaps a glitch? (I have same problem). Does anyone know about this please ?


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