Replacing glow plugs 97 7.3

[THicks444]

I was hoping someone could tell me how hard it is and how to do them? Meaning more complicated parts, I'm sure for the most part I can figure it out, also what kind of problems might I encounter and what should I do? For example I've heard of glow plugs swelling and not wanting to come out?

[bugman]

Here is a write up that Believer45 has. It was originally done by another member by the user name of Carpenter.

Glow Plug Replacement and Glow Plug Relay Swap.

All additions/edits done in red were added by Dave / Believer45 to either make a minor correction, to clarify a procedure or add my comment/experience.

This article is specific to the 94-97 trucks. 99 and up 7.3 is similar but uses one plug on each side instead of two and there may be two relays instead of one where the glow plug relay is. The second (shorter) one is for an intake heater and no they are not interchangeable.

I came across a post that mentioned a Dorman part number 615202 that includes one valve cover gasket, two under valve cover harnesses and two outside plugs with pigtails. As of January 2009 PartsFactor.com sells it as a kit for $48.15 plus shipping, an incredible deal.

Updated October 27, 2001, done by Carpentractor, member of thedieselstop.com (formerly ford-diesel.com)

As winter took its foothold, I started to notice a problem starting my truck. Since Winter did not really get in here 'til late December I was under the assumption that my glow plug system was hunky dory. Well, the first snowfall and 20 degree day showed me otherwise. To get the truck to even start I had to jump the relay lugs. When it did start it surged and bucked something awful. My truck has little problem starting without glow plug assistance or engine warmth when temperatures are higher than 35 degrees F. When temperatures were lower than 35 degrees F the Engine starts like an old jalopy with shakes and stirs with a whole lot of black and white smoke. This as matched the symptoms of a malfunctioning glow plug system. I was forced to use the plug in block heater before using the truck. Usually an hour plugged in would be fine for an unassisted start and if I ventured out I had to insure that the truck ran every 2 hours or so to allow further unassisted starts. After living a week with this I decided it was time to rectify this problem!!! Diagnosis....I was reasonably certain that I had problems with glow plugs due to the fact that even when I jumped the main lugs of the relay with a pair of pliers the truck still started hard. I wanted to confirm my suspicions and attempted diagnosis. I don't want to confuse you so I will tell you how you should diagnose the glow plugs and not how I did it. I luckily ended up finding some bad ones. I didn't do it completely the way I say below, as I omitted checking the two rearward connectors' pins. On to Proper Diagnosis. There are Four (4) electrical connectors that are part of the valve cover gasket. These connectors need to be removed and once removed they reveal Five (5) pins. The picture below shows the valve cover off and the valve cover gasket in place.


On each connector the center three are used for the injectors. The two outer pins are connected to one glow plug each. There are 4 connectors equaling total of 8 glow plugs. To test the glow plugs you will need a multimeter that reads ohms. (comment added by Dave / Believer45) I find a digital multimeter necessary, it is too hard if not impossible to see the difference between 0 and 0.5 ohms resistance on a sweep style meter. You can touch the pins with the meter leads but I used alligator clip test leads to assist me in this endeavor. I hooked up a black test lead with one clip to a good clean ground and the other to the common lead from the multimeter. I hooked up a red test lead clip to the ohms lead of the multimeter and the other one I clipped to each one of the pins I wanted to test. You would then move this clip to each of the 8 pins and record the readings.

The ohms value for any given pin (plug) should be between (.1) and ( 6) ohms. If you are getting a higher or open line (OL) reading you may have a bad glow plug. With higher values than 6 ohms or OL values you definitely have concern for opening up the valve cover/s and investigating further. Remember if you are testing the engine hot you will get a slightly higher resistance reading than you will when the engine is warm. On mine I noticed it was about 3-4 ohms higher than cold after being shut down for 2 hours on a 65 degree day.. Of the ones I tested, I had two bad ones. I then went out to my local Autozone to pick up some new OEM parts. Autozone sells the original Beru Plugs in Motorcraft packaging. The stock number for the Powerstroke is ZD-10. (ZD-9 for the IDI). (comment added by Dave / Believcer45) RECENT PART NUMBER CHANGES MAKE THE PART NUMBER ZD-11 FOR OUR TRUCKS SO DOUBLE CHECK YOUR PART NUMBER (added 9/4/2004) AutoZone no longer stocks/sells the Beru/Ford glow plugs (added 10/1/2008) but they are often available on eBay. Just make sure you get the Motorcraft by Beru glow plugs. It pays to change them all so buy 8 because you do not want to repeat this job if you do not have to. They were $8.49 each. There can be a problem with a resistance test Before opening up the valve cover, it is a good idea to get everything above them out of your way. I chose not to remove the insulation on the A/C evaporator. I did remove most of the intake system before the turbo. I pulled all the intake plumbing off the engine from the air box to the turbo inlet. I also opened the air box and removed the filter. While this is not necessary, I did this because I use the air box as a handy bolt and tool holder. It holds all your tools and small parts, keeping them within arms reach at all times. It also keeps you from losing these parts nuts and bolts on the not so flat radiator support. I always remove all the bigger parts to an area of the truck where I know I will not fall, step or drop something on them. Typically I will put them in the bed of the truck so that they do not get lost or damaged during the repair. Organization is the key to a minimum stress repair. Once all the clutter is out of the way I can start the preparations for removing the valve cover bolts. I cleaned the head and valve cover mating area and high pressure oil rail of loose scale chipped paint and dirt. This keeps all that crap from getting inside the engine when the valve covers come off. After a good cleaning and once over I remove all the bolts. (comment added by Dave / Believer45) To access the rear bolt on the passenger side I find it easiest to remove the vacuum plenum chamber (a black plastic box about 3” x 6” x 1” attached to the heater blower housing with two screws, one vacuum line running to it) that is next to the passenger side rear corner of the engine, use a 6” extension 3/8 drive with a swivel socket (a universal joint and a regular socket are too tall) laid in the “V” formed by the heater blower housing and the firewall (pointed straight down). It helps me a lot to use an extension that locks into the socket so they do not separate on you in the tight space you have to work in. Once all the bolts are removed the cover lifts off with no effort. If there is any problem getting the cover off you probably have left a bolt that you may have overlooked. Once the valve cover is off you can see the gasket and the harness inside it. Inspect all the wires leading from the inside clip for burning or fraying. Remove the valve cover to a safe place and store it for later. Removing the Glow Plugs: Use a pair of needle nose pliers to remove the connectors from the tops of the plugs. They come off with moderate resistance. I have Craftsman tools and the glow plug requires a 10 mm deep socket for removal. The Craftsman 1/4 inch drive deep 10 mm. socket with the 3/8 inch to 1/4 inch adapter fits perfectly in the tight area the glow plug sits in. All other Craftsman deep wells were annoying at best to get inside the small space. I loosened the plug and then removed the socket. I used a tip from the Dieselmann's site that employs a 6 inch piece of 3/16" or 1/4" fuel line. Slide one end of the fuel line over the top of the plug after loosening the plug and then turn the tubing, the plug will unscrew and lift out on the tubing.. I have big fingers and plucking them out with my fingers would have been a pain in the butt. I removed all of the old plugs and then replaced them with new ones. The 1/4 inch fuel line works very well installing them too. After installing all four of them to rubber hose tightness I torqued them into place. Torque each plug to 14 ft lb. (168 inch lb..) Reconnect the glow plug connectors and insure that all the injector connectors are firmly in place before reinstalling the Valve Cover. Clean the Valve cover with carburetor cleaner or solvent and insure that the mating surface of the valve cover is clean and dry, free from any dirt or debris. Reinstall the valve cover torqueing the bolts to 8 ft lb.. (96 inch lb..). Repeat this procedure for the other side.

After I got the glow plugs installed I started to swap out the old glow plug relay. I never even went to Ford to price a new relay, as I had heard a new one neared $60. I just bought the Sorrenson model at Autozone for $16.99 Model MR-99. It is identical to the Napa GPR-109 and is the standard glow plug relay that was used in all earlier 7.3 IDI models. In order to do this swap on the 94 trucks and those that have a clip rather than ring terminals, for the activation circuit, some additional hardware is required. You will need : (12) inches of 16 ga wire. (2) solderless ring terminals #10 size. (2) solderless connectors 16 Ga., (2) 10-32 nuts and lock washers. At first I thought that the Sorrenson relay was not going to fit, as my relay looked nothing like this one does. The relay I had was significantly smaller, different shaped, equipped with two terminals and a water resistant clip. The new relay had 4 terminals on it two for the glow plug power cables and two smaller ones for the relay activation. The installation was easy. The new Sorrenson Relay bolts right into place with no modification at all.


The ring terminals for the glow plug cables fit fine, and with a little cleanup they went right on. I then had to cut the clip off the relay activation wires, and extend these wires with two 6 inch pieces of wire. The original relay activation wires to the clip are 20 Ga. or 18 Ga. and all the #10 ring terminals I found would only accept a minimum 16 GA wire. The solderless connectors would also only accept a 16 GA wire. So to solve this I dropped some strands of wire into the connector to take up space prior to making the crimp on the thinner wire. I used shrink wrap connectors to provide a nice seal against corrosion. I then bolted the smaller ring terminals onto the new Glow Plug Relay and tightened the larger ones. You will see the new smaller ones need to be bent slightly as they will interfere with the Engine cover if they are left as is.. Make these modifications as necessary then reinstall the engine cover. All in all this is not a bad job, it was straightforward and was not very complicated. With some tools and some patience this could be accomplished by almost anyone. It was nice to have her start like it was summer again. I want to thank all those at Ford-Diesel.com for pointing me in the direction of the Aftermarket Glow Plug Relay and the availability of OEM plugs at Autozone. Surely a Money Saver.

[Believer45]

If you would like a copy of Carpentractor's reply quoted above with pictures shoot me an email at Believer45@gmail.com with GLOW PLUG INFORMATION in the subject line, let me know where you saw this and what email address to use and I will reply with three attachments that may be of use to you.

Dave / Believer45

[agomez]

Back them out slowly, the metal that they are made of is real soft and can break leaving part of the plug in the head. My best advice is take your time and don't force breaking them loose.

[THicks444]

Thanks, came out without any problems, truck is back together and starts up great now on a cold morning, the worst part was getting at the bolts on the rear of the valve cover, passenger side especially was a pain in the neck

Sent from my PC36100 using AutoGuide.Com Free

[artificer]

An old thread, but I wanted to add my thanks to Carpenter, bugman, and Believer45.

Just bought a salvage 1997 F250 that was rolled. Lady driving it knew enough to reach up and turn off the engine while she was still sliding. Now that's admirable presence of mind in that situation.

Had to pull the glow plugs, rotate by hand, spin with starter, and replace everything. Didn't want to chance hydro-locking the engine, since it had sat on its roof for several hours. Good thing too... the passenger bank of glow plugs looked like I had just dipped them in motor oil, just dripping off. I'm glad I put the valve cover back in place before spinning the engine. Oil would have gone everywhere.

I ended up using a 3/8" drive extension, wobble adapter, and 13mm socket to get the pesky passenger rear VC bolt off/on. Just enough room with the vacuum tank removed. I'll be picking up a wobble socket for my other trucks maintenance. It had moderately new Beru GPs, so I'm a happy camper for now.

I've been putting off doing the injector o-rings and new glow plugs on my 1995 F250. Its been getting worse, and fuel mileage has suffered. Now that I've done it once, its a piece of cake.

Thanks again for the information.

Michael