red spark plug insolators?

[D]

My 91 explorer with 162000 miles has a slight miss from 1000 to 2500 rpms mostly when lugging or under heavy throttle but runs very strong above 2500. This has happend for a while now some times it is allmost gone and some times it's very noticeible. It seems that it is most noticible after driving for over an hour but i'm not quite positive on that. I have bosch platinum plugs, the othe day i pulled a few of them they were clean but the insolators the part under the electrode were all red! Probably from too much heat maybe they are the wrong plugs? What elese could cause these red insolators could this cause the miss. I was also thinking the fuel system could be the culprit maybe regulator, o2 sensor, or injectors? I have cleaned the mas airflow sensor, and put on taylor plug wires. Any one able to help?

[DOGMAN]

I would suspect the Bosch plugs. I installed a set and had problems after about 7000 miles, it would miss under moderate to heavy acceleration. Pulled the plugs and two of the insulators were cracked and many of the electrodes were out of wack. I installed a new set of stock Motorcraft plugs and the problem went away. Needless to say, I'm not a big supporter of the Bosch plugs. A couple of other guys on this site reported the same type of problems with their Bosch plugs on a thread about a month ago.

The easiest thing to do would be to buy a set of stock plugs (about $10) and install them and see if that fixes the problem.

[D]

thanks, thats whats next on my list oem plugs.

[Limited93]

Originally posted by D
thanks, thats whats next on my list oem plugs.

Hi,

With the experience that I just had with OEM Motorcraft platinum spark plugs, I wouldn't do it if I were you. I had less than 2,000 miles on my Motorcraft plugs and they dropped two electrodes in my engine. I'm not a Motorcraft fan any more.

Limited93

[DOGMAN]

I was referring to the stock Motorcraft plugs that are specified for my 91, not the Motorcraft Platinum plugs.

[Limited93]

Originally posted by DOGMAN
I was referring to the stock Motorcraft plugs that are specified for my 91, not the Motorcraft Platinum plugs.

According to the Ford computer and the information that I got at the auto parts store the Motorcraft Platinum plugs are recommended for my 93, 4.0 engine. There is Autolite plugs in the motor now and there is no problem, other than the valve slap out of the exhaust from the shattered valve that was ruined thanks to the Motorcraft plugs.

Limited93

[Rhett]

I wouldn't be so quick to discredit Motorcraft. Like I said in the other thread you might have had oil leaking into #5 causing it to blow. In that case, it wouldn't matter what plug you had in there, they would all die.

[Limited93]

Originally posted by Rhett Browning
I wouldn't be so quick to discredit Motorcraft. Like I said in the other thread you might have had oil leaking into #5 causing it to blow. In that case, it wouldn't matter what plug you had in there, they would all die.

If leaking oil was the cause of the valve shattering, what caused all six plugs to burn hot and two of them to have their contacts burnt off and the eloctrodes landing in the cylinders? I have never seen oil shatter a plug and that goes for my oil guzzling '55 Ford, that was my first car that I owned out of high school. That car burned more oil than it leaked, but it got me where I wanted to go and the motor didn't jump around like a stuck pig. I never had a valve go on that motor. Oil in that old dog came out of everywhere. I couldn't expect much for a $100 car. Back then we didn't think much about blue smoke coming out of the tail pipe, we were lucky to have a car at that age. There is no indication that the motor in the Explorer uses any oil.

Limited93

[Rhett]

Since you say it wasn't using oil, in your case it sounds more and more like the plugs used were not of the proper heat range. You say they were MC plugs, but do you know if they were the correct Motorcraft plugs for your engine? The installer might have mistakenly put Mustang plugs in there. How about the gap on them? It just sounds like the heat range was off on the plugs.

[Limited93]

Originally posted by Rhett Browning
Since you say it wasn't using oil, in your case it sounds more and more like the plugs used were not of the proper heat range. You say they were MC plugs, but do you know if they were the correct Motorcraft plugs for your engine? The installer might have mistakenly put Mustang plugs in there. How about the gap on them? It just sounds like the heat range was off on the plugs.

Hi Rhett,

Yes they are the right number for this motor. I went to a local Auto parts store that sells Motorcraft and they said that the numbers match for my Explorer's engine.
Now I'm wondering if all platinum plugs burn too hot for the Explorer 4.0 engine. Since someone posted that their Bosch platinums went and there is supposed to be more posts of the platinums going in the Explorers I wonder if it is the metal that the electrodes are made of cause them to burn hot. All of the plugs show some sign of heat on the insolators, but only two had the contacts burnt completely off and the electrodes out of them.
Ford isn't interested in backing up their products. I went to see a lawyer in my home town. He said it wouldn't be worth it for him to take the case because the dealership isn't in this county. Now I have to find a lawyer in the county that the dealership is in. He also suggested that I have to find someone that will swear that these plugs are defective. Now how in blazes am I supposed to do that?

Tom Murray
(Limited93)

[Rhett]

It seems to me that this Ford $tealership should stand behind their work! That is if they want to keep a good reputation. From what you have said, you must have already tried talking to them person-to-person, and showing and telling them what happened, and they said "We aren't liable". Well, unless your engine had no coolant in it or something like that, they should be liable for the damage done because they are the ones that installed the plugs.

I don't know what they did, but they must have installed them incorrectly (didn't thread them in, didn't gap them, etc.). They should be able to get that right, it's not too tough. I like to do things like that myself since I don't trust some of them to touch my Explorer. The ASE guys are great, but many times they are doing big jobs and don't mess with simple jobs like changing plugs, and the responsibility is delegated to some kid. I don't let kids touch my vehicles anymore; I have had enough bad experiences with inexperienced mechanics.

I have never heard anything about platinum-tipped plugs being bad for the 4.0 OHV. My understanding is that the only diff between copper and plat tips is how long they last, not heat range. Perhaps they do have diff heat characteristics but I don't think so. I have heard things about Bosch+4's being hot plugs.

The manufacturer of my spark plug wires recommended I use a single-electrode Autolite Platinum spark plug with their wires, which I did. I have had no problems with them.
The Motorcraft plugs that were in there were Motorcraft Platinums. I think they were the original plugs, so Ford put in platinums at the factory.

But back to the main point; don't let that dealership get away with not standing behind their work. I would not try to deal with Ford in Detroit, they're too big. But that dealership should be the focus of efforts. They should at least pay you to have the damage fixed. I know you wouldn't let them fix it, though!

[Limited93]

Originally posted by Rhett Browning
It seems to me that this Ford $tealership should stand behind their work! That is if they want to keep a good reputation. From what you have said, you must have already tried talking to them person-to-person, and showing and telling them what happened, and they said "We aren't liable". Well, unless your engine had no coolant in it or something like that, they should be liable for the damage done because they are the ones that installed the plugs.

I don't know what they did, but they must have installed them incorrectly (didn't thread them in, didn't gap them, etc.). They should be able to get that right, it's not too tough. I like to do things like that myself since I don't trust some of them to touch my Explorer. The ASE guys are great, but many times they are doing big jobs and don't mess with simple jobs like changing plugs, and the responsibility is delegated to some kid. I don't let kids touch my vehicles anymore; I have had enough bad experiences with inexperienced mechanics.

I have never heard anything about platinum-tipped plugs being bad for the 4.0 OHV. My understanding is that the only diff between copper and plat tips is how long they last, not heat range. Perhaps they do have diff heat characteristics but I don't think so. I have heard things about Bosch+4's being hot plugs.

The manufacturer of my spark plug wires recommended I use a single-electrode Autolite Platinum spark plug with their wires, which I did. I have had no problems with them.
The Motorcraft plugs that were in there were Motorcraft Platinums. I think they were the original plugs, so Ford put in platinums at the factory.

But back to the main point; don't let that dealership get away with not standing behind their work. I would not try to deal with Ford in Detroit, they're too big. But that dealership should be the focus of efforts. They should at least pay you to have the damage fixed. I know you wouldn't let them fix it, though!

Hi Rhett,

Yes, I did go back to the dealership. They said the there is no evidence that the plug electrodes took out the valve.
I also went as far as the service department in Detroit to file my complaint. After being put on hold for a while. I was told that I have to have a Ford service manager say that the plugs were defective and that they caused the valve to shatter. I told the lady that is like asking the fox that is whatching the hen house. I told her the service manager at the Ford dealership said that there was no evidence that the plugs caused the valve problem. Then I told her I'm going to get a lawyer. Her only reply was, "I'll put that in my report". Lets put it this way. This is the last Ford for me.
The next thing I'm going to do this summer while I'm on vacation, is to ask around the local car club and see if anyone has put a Toyota drive train in a Ford Explorer. If anyone there wants to give me some advise, I'll do that conversion. I wouldn't own a chevy, I'm not into any other American car brand. Ford was my last bastion other than Olds. They are not going to be making them any more. I'll just stick a thumb in Fords face and put a nice mural on the back of this Explorer and put on there Toyota powered. :-)
Now I still have to find a lawyer in the next county. I have some friends that are looking.

Have a nice day,
Tom Murray
(Limited93)

[93Blue2door]

I read that you can't use platinum plugs with turbo because the high heat vaporizes the platinum. Perhaps the 4.0 gets too hot to use platinum and that's what happened to yours. Good old fashioned copper is the best.