Gentlemen, I'm contemplating buying a 1997 Mustang GT from a local Ford dealer. Very nice car with 107,000 miles. It's black and has a 5 speed transmission, both big +'s for me. My concern is the spark plug ejection issue on the 4.6 modular engine. Near as I can tell the 1999-2003 were the worst years for spitting out plugs, but I am not for sure about that. Can any of you confirm this? What is your experience? FWIW, a friend of mine has a 1998 F-150 with the 5.4 and has never had one blow out. This truck has 275,000 miles on it. She bought it 8-9 years ago with 100,000 miles. Thanks for your comments.
1997 Mustang GT spark plugs!
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ls1mike
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It does happen but is fixed fairly easily. Do you know if the plugs have been done?
Not sure about 1997. I know the guy I work with has an 02 Ford F-150. He is at 118,000 and it has blown two out in the past 10,000 miles. I think if he had changed them sooner he would not have had the problem.
If the car is clean and priced right. I would not let that stop me from getting it.
Not sure about 1997. I know the guy I work with has an 02 Ford F-150. He is at 118,000 and it has blown two out in the past 10,000 miles. I think if he had changed them sooner he would not have had the problem.
If the car is clean and priced right. I would not let that stop me from getting it.
the NPI heads like on your 97 didn't do it as often as the PI headed models. That being said, it can still happen.
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Sounds like an awesome car! My friend had a 96 and drove it till it had over 300,000 miles on it. Got rear ended on the interstate and totalled it :^(
The npi head modulars had more threads holding the plugs in then the pi head versions that followed.
Still a very reliable engine capable of many hundreds of thousands of trouble free miles.
Right out of the box the pi engine had more hp. They were almost equal in tq and had potentially less problems than the pi head engines.
Still a very reliable engine capable of many hundreds of thousands of trouble free miles.
Right out of the box the pi engine had more hp. They were almost equal in tq and had potentially less problems than the pi head engines.
The spark plug blowers are typically 99-03 with the 5.4L engine on F150 Supercrew and Expeditions. The plug is usually the number 4 plug, which is the plug furtherest back on the passenger side, which is also the most difficult to get at. Main part of the problem is that the AC condenser hose runs right over the spark plug hole. The hoses leak condensation right into that hole. The spark plugs are iron and the heads are aluminum, dissimilar metal problem and makes that particular plug get weaker until it's too late. There is a fix if it happens, either a helicoil or an insert.
Mustangs don't seem to launch plugs as often, but that could just be the production volume.
As Schmoe pointed out, the likelihood of encountering this problem and how bad it is to fix depends a lot on the underhood packaging.
I have seen a few 5.4s with blown plugs. Always 5.4s, and always in an F-150 or Expedition. One had the blown out coil held in place with paint mixing sticks.
I actually haven't even heard of it happening on a Mustang come to think of it. I've known a number of people with 4.6 Mustangs, a couple heavily modded. Never heard of one spitting a plug, including one NA 4.6 that would run out of speedometer before it would run out of steam.
Even on a early 2000s 5.4 powered truck, I wouldn't be that worried anymore since fixes are known and plentiful.
As Schmoe pointed out, the likelihood of encountering this problem and how bad it is to fix depends a lot on the underhood packaging.
I have seen a few 5.4s with blown plugs. Always 5.4s, and always in an F-150 or Expedition. One had the blown out coil held in place with paint mixing sticks.
I actually haven't even heard of it happening on a Mustang come to think of it. I've known a number of people with 4.6 Mustangs, a couple heavily modded. Never heard of one spitting a plug, including one NA 4.6 that would run out of speedometer before it would run out of steam.
Even on a early 2000s 5.4 powered truck, I wouldn't be that worried anymore since fixes are known and plentiful.
One of my old Mustangs was a 97. No worries as they didn't have the problem. Torque to spec and all is good.
I can say that after having my '02 GT for 10 years now, working as a tech for quite a few years, working on mustangs in the mustang club im in, I've never seen condensation dripping on the plug and causing any problems.
I'm not saying it can't happen, but after seeing hundreds of these cars I've never seen one have that problem.
They changed the number of threads on the plugs to help the issue of them blowing out. Also, every one I've helped fix were because of improper tightening or just someone not paying attention to the tick that usually occurs for a good while before the plug blows.
The best bet on the 4.6's and 5.4's for those years is to double check the plugs after a few heat cycles just like it's suggested to do with lugnuts.
I'm not saying it can't happen, but after seeing hundreds of these cars I've never seen one have that problem.
They changed the number of threads on the plugs to help the issue of them blowing out. Also, every one I've helped fix were because of improper tightening or just someone not paying attention to the tick that usually occurs for a good while before the plug blows.
The best bet on the 4.6's and 5.4's for those years is to double check the plugs after a few heat cycles just like it's suggested to do with lugnuts.
Is there a record book of repairs with that car? If there was, you could find out if a spark plug was ever blown out or not.
Never had anything go bad with spark plugs on mine, owned it for 11 years, changed spark plugs and wires about 6 years ago. It has been a fairly reliable vehicle . Odometer is stuck at 90k, guesstimated to have around 180k, smokes but still runs strong.
Originally Posted By: laserred96gt
Never had anything go bad with spark plugs on mine, owned it for 11 years, changed spark plugs and wires about 6 years ago. It has been a fairly reliable vehicle . Odometer is stuck at 90k, guesstimated to have around 180k, smokes but still runs strong.
http://www.latemodelrestoration.com/item/LRS-17255OG/94-98-Mustang-Odometer-Repair-Gear-Kit
here you go. I did it on my 95 and it fixed the odometer. I also took the cluster assembly apart and replaced all the bulbs and clean everything up.
Never had anything go bad with spark plugs on mine, owned it for 11 years, changed spark plugs and wires about 6 years ago. It has been a fairly reliable vehicle . Odometer is stuck at 90k, guesstimated to have around 180k, smokes but still runs strong.
http://www.latemodelrestoration.com/item/LRS-17255OG/94-98-Mustang-Odometer-Repair-Gear-Kit
here you go. I did it on my 95 and it fixed the odometer. I also took the cluster assembly apart and replaced all the bulbs and clean everything up.
Originally Posted By: bdcardinal
Originally Posted By: laserred96gt
Never had anything go bad with spark plugs on mine, owned it for 11 years, changed spark plugs and wires about 6 years ago. It has been a fairly reliable vehicle . Odometer is stuck at 90k, guesstimated to have around 180k, smokes but still runs strong.
http://www.latemodelrestoration.com/item/LRS-17255OG/94-98-Mustang-Odometer-Repair-Gear-Kit
here you go. I did it on my 95 and it fixed the odometer. I also took the cluster assembly apart and replaced all the bulbs and clean everything up.
Thanks man, I will look into that.
Originally Posted By: laserred96gt
Never had anything go bad with spark plugs on mine, owned it for 11 years, changed spark plugs and wires about 6 years ago. It has been a fairly reliable vehicle . Odometer is stuck at 90k, guesstimated to have around 180k, smokes but still runs strong.
http://www.latemodelrestoration.com/item/LRS-17255OG/94-98-Mustang-Odometer-Repair-Gear-Kit
here you go. I did it on my 95 and it fixed the odometer. I also took the cluster assembly apart and replaced all the bulbs and clean everything up.
Thanks man, I will look into that.
Originally Posted By: laserred96gt
Originally Posted By: bdcardinal
Originally Posted By: laserred96gt
Never had anything go bad with spark plugs on mine, owned it for 11 years, changed spark plugs and wires about 6 years ago. It has been a fairly reliable vehicle . Odometer is stuck at 90k, guesstimated to have around 180k, smokes but still runs strong.
http://www.latemodelrestoration.com/item/LRS-17255OG/94-98-Mustang-Odometer-Repair-Gear-Kit
here you go. I did it on my 95 and it fixed the odometer. I also took the cluster assembly apart and replaced all the bulbs and clean everything up.
Thanks man, I will look into that.
If I knew it was this easy I would have done it a long time, I was quoted $300 so I never bother to fix it. I already took it apart , waiting for the gears to get shipped.
Originally Posted By: bdcardinal
Originally Posted By: laserred96gt
Never had anything go bad with spark plugs on mine, owned it for 11 years, changed spark plugs and wires about 6 years ago. It has been a fairly reliable vehicle . Odometer is stuck at 90k, guesstimated to have around 180k, smokes but still runs strong.
http://www.latemodelrestoration.com/item/LRS-17255OG/94-98-Mustang-Odometer-Repair-Gear-Kit
here you go. I did it on my 95 and it fixed the odometer. I also took the cluster assembly apart and replaced all the bulbs and clean everything up.
Thanks man, I will look into that.
If I knew it was this easy I would have done it a long time, I was quoted $300 so I never bother to fix it. I already took it apart , waiting for the gears to get shipped.
Originally Posted By: Kruse
On this engine, I think the chance of them blowing out depends on how well the plugs were put in during the last plug change. If done properly, I would imagine they will stay in without blowing out.
This.
This biggest issue was from over-tightening. Since there were few threads, over-tightening would damage them and then you'd have flying sparkplugs. Under-tightening was a secondary problem. Use a torque wrench and set it to factory spec (11 ft/lbs) and there will be no issue.
On this engine, I think the chance of them blowing out depends on how well the plugs were put in during the last plug change. If done properly, I would imagine they will stay in without blowing out.
This.
This biggest issue was from over-tightening. Since there were few threads, over-tightening would damage them and then you'd have flying sparkplugs. Under-tightening was a secondary problem. Use a torque wrench and set it to factory spec (11 ft/lbs) and there will be no issue.
Gentlemen, thank you for your comments. It is a nice car but the dealer and myself cannot agree on a price. Probably not going to happen. They seem to want to sit on it and plow snow around it all winter, which is fine by me. They should be able to get their price for it this spring, but not now.
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