Ford Spark Plug Blow Out – Solved

WiseAutoTools.com © Summary: This is one of our more extensive articles on spark plug thread repair. If you need answers fast to get a vehicle up and running quickly we understand. No time to read? We’ve got answers, give us a call at 800-734-8665 x251. To continue some research by reading 10-15 minutes see below.

Ford spark plug blowout repair using a kit over the fender. Most common engines that have the problem are Ford 4.6, 5.4 & 6.8 liter engines, although any engine can have this issue. If unsure of which spark plug thread repair kit is right for your engine, we can assist. Just give Dennis a call (he’s a Master Tech shown in the video below demonstrating the Time Sert 5600 kit). We have been helping Ford owners and repair shops with this common problem since 2005. For more information on this repair, read on. Be sure to see the highlighted text for a brief rundown on our most popular kits and size holes the kits can be used on. You may also ask a question by using our Contact Form, be sure to let us know what you’re working on. Please provide the year, make model, size engine and outside diameter of the failed insert if you know – or let us know if this is a first time repair.

Call us! We’re only a phone call away – 800-734-8665. Read on for more info on how to fix stripped threads due to spark plug blow outs. See the links below for the best kits to fix it yourself. These are considered “permanent” type repairs as opposed to the parts store kits that just put a Band-Aid on the problem. Parts store repairs usually blow back out.

There are many different brands of spark plug thread repair kits on the market today for the common Ford spark plug blowout problem. The repairs are not all equal. We’re familiar with the best thread repair kits and with some that usually end up failing. Sometimes the lower end kits blow out again while driving and sometimes the repair insert comes out with the sparkplug during a tune up. Since you’re reading this, you may already know that some Ford dealers write repair estimates for thousands of dollars to replace the cylinder heads when a spark plug blows out. If your vehicle has had a quote like this: your research here, will be rewarded shortly. We have many do it yourselfers purchase kits from us and do the repair themselves. Some decide to purchase the kit and have their regular mechanic do the work. We also have many shops purchase kits after reading our information. Some Ford dealers are regular customers, after purchasing a kit they return for replacement inserts.

Our oversized spark plug thread repair kits fix “parts store brand” failures and can be done in the vehicle, without removing the cylinder head. Based on cost and results; the Calvan 38900, the Time Sert 5553 and the Time Sert 5600 are the best thread repair kits on the market for fixing threads when an inferior kit has failed. We've had great feedback on these kits since 2005! Based on our customer’s feedback we know what works. Our kits come with steel alloy thread inserts which share similar properties with aluminum, so there’s no issues with grounding properly. Steel alloy is about ten times stronger than aluminum! We have aluminum inserts available for the 5553 kit for certain racing applications. But for normal applications steel is better.

The Time-Sert 5600 has the largest outside diameter insert available (almost 3/4″) which can be used when a previous repair has made the hole too large for other kits. The Time Sert 5600 also works for more applications than the Calvan 38900 does. We have the “How to” video (below) that demonstrates how to use the largest kit available (Time Sert 5600) to finally fix the dreaded “repeat” blown out spark plug that has left the hole too big to fix for regular kits.

We’ve sold thousands of these spark plug thread repair kits, saving Ford owners a lot of time – and money in the process. We’ll explain why this should be the next and last “over the fender” repair (even in vans) purchased for this particular application. Again we can assist with choosing the correct kit, but below is a basic guideline for Ford 4.6, 5.4 & 6.8 engines that use M14x1.25 spark plugs. Also a video I did on an F150 using the Time Sert 5600 kit.

Time Sert 5553 – Repairs spark plug holes smaller than .663″ (16.8mm).

The outside diameter of the insert is .69″- it’s Double Over-sized, used on many applications and has a Triton counter-bore needed for some 2001 and up. *Note Add-On Kit 5588 for repairing holes larger than .663″ (16.8mm) repairing holes up to .73″. Works for SOHC and DOHC engines. The original size plug M14x1.25 is used. This kit is Made in the USA.

Time Sert 5600 – Stand Alone Kit that repairs spark plug holes larger than .663″ (16.8mm).

Uses one insert inside another one. The outside diameter of the largest insert is .77″ – it’s Triple Oversized. Used on many applications and has a Triton counter-bore needed for some 2001 and up.*Note Add-On Kit for installing the Double Over-sized inserts for holes smaller than .663″ (16.8mm) is kit number – 5588. Works for SOHC and DOHC engines. The original size plug M14x1.25 is used. This kit is Made in the USA.

Calvan 38900 – Repairs spark plug holes up to approximately .678″ (17.24mm).

.678″ is the reamer O.D. size. The outside diameter of the insert is .73″. We also have this kit available with one insert which is priced lower – CAL38900-1. Due to the guide being required this kit has a limited application (compared to Time Sert ). Fits only Ford SOHC 4.6, 5.4 and 6.8 engines from around 1996 to 2016. See the 38900 product listing for more details on application. Since there’s no counter-bore for certain engines from 2001 and up for this brand, we recommend the Time Sert kits listed above for those applications. The 38900 works for only certain SOHC engines. The original size plug M14x1.25 is used. This kit is made with Globally Sourced Components. 

Win Tools 389XL– Repairs spark plug holes up to approximately .75″ (19mm).

The 389XL is kit has a slightly larger O.D. (Outside Diameter) than the 5600 kit. It uses one insert per hole and has a guide like the 38900 kit does. In fact it is the same design as the 38900 just larger inserts and tooling. This kit is a less expensive alternative to the 5600 kit when an extra large repair is needed when previous repairs have made the hole larger than normal. The 389XL has been used successfully when the 38900 has failed.

Ford 3V Engines

Note that 2004 and up 3V engines use a different spark plug thread repair kit – Calvan 39300 or Time-Sert 3221. The Calvan 38900 is for 2V, SOHC engines from around 1996-2016, if working on a DOHC InTech engine, use Time-Sert 5553 or 5600. If working on an 01 or up SOHC with M14x1.25 plugs the Time Sert 5553 or 5600 is our top choice. If working on a 2004-08 3V engine with M16x1.5 spark plugs use the Calvan 39300 or the TIME-SERT 3221. If working on a 2008 and up 3V engine with M12x1.25 use the 4212H.

More on Ford Spark Plug Blow Outs – What causes it?

Ford spark plugs blowing out is a common problem with engines in Ford F150 pick up trucks, Mustangs, Crown Victorias, Vans, Expeditions and motor homes. A video showing spark plug thread repair using the Calvan spark plug thread repair kit being used can be viewed on the Calvan 38900 description page. Read on for more information.

Ford 4.6, 5.4 and 6.8 modular engines are prone to spark plugs being blown out of the cylinders due to the aluminum threads failing. If the spark plugs are not tight enough the spark plug vibrates until the aluminum is weakened to a point the spark plug shoots out. Some blame faulty aluminum, but there are no other issues with any other part of the heads. Ford originally had a lower torque specification and later revised it making the torque spec higher and plugs tighter. When the threads are about to come loose there is often a slight ticking sound/noise, like a small “exhaust manifold leak” would sound. As stated before, the problem usually starts if the spark plug is loose. The coil keeps the plug from backing out completely. The spark plug vibrates until the aluminum threads in the cylinder head are deteriorated to a point that the spark plug ejects from the pressure of the compression from the cylinder. The spark plug ejecting typically breaks the coil on the way out.

Although rare, it’s possible an engine compartment fire can start due to the raw fuel escaping the engine cylinder and the broken coil can provide the spark. We have many Ford dealers that use Time Sert and Calvan, however there are some Ford dealers that will not recommend repairing the threads. Many only recommend replacing the cylinder head. Because of the cost of labor and parts involved in replacing the heads, we recommend using the appropriate thread repair kit made by Time Sert or Calvan. After the repair the threads will be stronger than original.

Below is another reason we recommend using the over the fender repair as opposed to removing the heads.

Gaining access to the cylinder head bolts and removing the heads is difficult on trucks and SUV’s. To remove and re-torque the heads, most Ford technicians do a “cab off” or “body off” operation. On trucks the cab is unbolted from the frame; on SUV’s and vans the entire body is unbolted from the frame, the electrical wiring, AC lines, radiator hoses, heater hoses, master cylinder, etc. are disconnected. This allows the tech to use the vehicle lift to raise the cab or body off of the frame. Once this is done the engine can be serviced much easier. This process takes less time than you might expect after the tech has done a few of these and knows exactly what needs to be done. However, using one of our kits and eliminating the need to do all that extra work is obviously the most cost effective method.

Below explains the difference between HeliCoil and the Time Sert and Calvan type insert.

Many techs at repair shops will use a Heli-coil repair kit to install a new Heli-coil insert. Techs are familiar with HeliCoils that are good for many applications. Many times, the name HeliCoil is used as a generic name for a thread insert. This is similar to how some people say “Kleenex” but they are really using the word as a generic term for facial tissue. Just to clarify though; The Time Sert and Calvan type inserts are NOT the same as the Heli Coil. The Time Sert and the Calvan inserts are much thicker and much stronger and will not leak compression. They also last the life of the vehicle. That being said, I actually have used the Heli-coil (wire coil) repair kit on two different occasions (years before I started selling tools) and neither of them failed that I am aware of. Sometimes they fail when the spark plug is removed on the next plug change. One concern of using the Heli-coil is that combustion pressure may escape the cylinder since the spark plug may not seat perfectly. I am also aware of a very experienced tech (also an ASE Master Tech) I used to work with, that installed a Heli-coil. However it did fail within a week after it’s installation. The cylinder head was removed and sent to the machine shop, subsequently it was deemed as “not repairable” by the machine shop. If we would have only known about the Time Sert and Calvan repair kits back then, the cylinder head could have been saved. This is because the Time Sert and Calvan inserts are much thicker and are large enough to repair a spark plug hole that has had a Helicoil fail previously. In fact, we commonly sell to customers that have had a Heli-Coil or Sav-A-Thread repair fail and blow back out. We also have had many customers that have tried cheap parts store kits that only bought them a little time, before they were back in the same situation, with a Blown spark plug.

DenLorsTools.com and WiseAutoTools.com has sold many Time Sert and Calvan kits over the years. The kit numbers listed on this page have had no reported failures! One of the best features is that the spark plug thread repair inserts can be installed over the fender without the need to remove the cylinder head.

Using the Time Sert or the Calvan Kits
These kits have much thicker inserts that can be used when other thinner repairs like the Heli-coil or Sav-A-Thread have failed to hold. Using these kits require about the same access as if you were changing the spark plugs. Just a few steps more. The instruction videos that we provide, layout details on using the kits. Upon request when purchasing from us, we provide a compilation of the tips we think are important when using these kits. These tips are emailed to our customers upon purchase. We will also personally answer questions if needed, but we’ve found the tips clarify the job.

At checkout just write “Tips” in the Comments field and we will email the tips when processing the order.

Additional Tips

Emailed free after purchase.

Time Sert products are proudly made in the USA – Reno Nevada. Horizon Tools (North Carolina) provides us with the Calvan Kit, also sold as Mount9200 and other labels including Blue Point (sold by Snap On for about twice the price). Many of our customers with 4.6 or 5.4 or 6.8 engines, decide to put inserts in all cylinders. Some only fix the failed ones and check the tightness on the others. Either way, this helps prevent the possibility of any future spark plug blow-outs.

Basic Tool List
1. Standard Pliers (not included) 5/8″ Spark Plug Socket (not included)
2. 3/8″ Drive Extensions (not included)
3. Inspection Scope/Camera (not included) – Use to check for metal in cylinder.
4. Air Ratchet (not included) If a good quality air ratchet is not on hand we can ship one at the same time.
5. Starter Button-optional (not included) Manually turning the engine with a socket and ratchet on the crank bolt eliminates the need for a starter button.
6. Cylinder Leak Detector (included in 38900 kit) Available separately.
7.  Air Blow Gun with 8-12″ of Small Tubing (not included)
8. Safety Glasses (not included)
9. Lubrication like PB Blaster or WD40 (not included)
10. JB Weld (not included) Loctite is included in the Time Sert kits
11. 3/8″ Ratchet (not included)
12. Shop Towels (not included)
13. Air Compressor (not included)
14. Brake Cleaner, to help clean out the cylinders and provide clean threads for loctite or JB Weld to adhere to.

Below are a few of the questions we’ve answered over the years about Ford Spark Plug Blowouts.

Question: I have a 1999 Ford F150 with a 4.6 liter Triton engine with 126,000 miles on it. The number 3 spark plug blew out of the cylinder head. I called my local repair shop and was told that this was a common problem with this design engine because of the extremely thin (aluminum) casting in the spark plug area of the engine head, there is only about five threads for a spark plug. How are your inserts better?

Answer: While it is true there are only five threads for the spark plug in this design engine for the spark plug and the Calvan insert has five spark plug threads as well, the Calvan spark plug insert is steel not aluminum and the insert itself is held in place with ten external threads. The Calvan spark plug insert improves the design and durability at fraction of the cost of replacing the cylinder heads with the same design weakness. Time Sert offers fully threaded inserts PN 51457.

Question: I am selling my truck as fast as I can get a spark plug to stay in long enough to get rid of it. I wanted to use a Heli-coil because I won’t have to drill, but the thread tool isn’t long enough to reach in the spark plug recess, any suggestions?

Answer: I personally recommend the Time Sert or the Calvan tools because they are a better repair, but if you would rather use the thinner Heli-coil insert, the HEL5396-14 has the longer thread tool than the standard Heli-coil kit.

Question: I have Ford van that has had a Sav-A-Thread installed previously, it has blown out and I want to know if the Calvan insert will work since the Sav-A-Thread has left a bigger hole now?

Answer: Yes, the Calvan spark plug repair insert is a larger insert and has worked well for our customers before, saving the expense of replacing the heads. The Time Sert 5600 has the largest outside diameter and therefore can save heads that have pretty large holes. In fact up to .73″.

Question: I bought a rebuilt head and come to find out one spark plug holes had a repair insert, it blew out last week. The cylinder head has a warranty, but I cannot afford the down time all over again. Will the Time Sert or Calvan insert repair this hole?

Answer: Yes, the Time Sert or the Calvan inserts, both have thicker beefier repair inserts that you don’t have to worry about. And I always tell our customers that when purchasing a rebuilt head of this type to be aware of the possibility that inferior repair inserts may already be in the head. Buying a brand new head would insure that there are no cheap inserts, but you would be stuck with the original weak design. Either the Time Sert or the Calvan thread inserts will save down time, money and are stronger due to the material being steel alloy instead of aluminum like the original threads.

Question: Why are these kits so expensive? I can buy a $20 kit at the parts store.

Answer: The short answer is you get what you pay for. The kits we sell are considered a permanent type repair as opposed to the parts store kits which are temporary at best. Our kits also have longer tooling to fit down into spark plug wells. Our kits don't required hitting the insert with a hammer. Our kits either have a guide or have piloted tooling to keep the repair insert straight. Our inserts cannot be screwed too far. Parts store inserts have no "stop" which allow them to be screwed all the way down in the engine if the installer is not careful. We usually get calls from customers after they have used a parts store insert and have dropped it into the cylinder or the insert has blown back out making the hole bigger, requiring an oversize repair; or in the case of the Dorman, they have been breaking in half recently. This required removal before any of our kits can be used.

Question: I had a spark plug blow out on my 2004 3.8 V6 Ford Mustang Convertible. Which spark plug thread repair kit and insert would I need?

Answer: Ah yes, the V6 rarely has this issue however it's possible to have stripped spark plug threads on any engine that leads to a blowout. The short answer is the 4412 and 44186 inserts if it's a first time repair. See the 2004 Ford Mustang thread kit selection page for more information. 

FYI- We are working on a Thread Repair Lookup Tool to help find thread repair kits for different applications. It is a work in progress, so if you don't find what you need there please inquire using the info below.

For even more information, see our main page with many more articles and videos on how to repair stripped threads.

We've been selling specialty tools and aluminum thread repair kits since 2005. Call for assistance in finding the best spark plug thread repair kit for your situation at 800-524-9783 or 800-734-8665 x251 or provide your details by using our Contact Form.