Boozer Posted February 22, 2005 Report Share Posted February 22, 2005 I have bought new bosch platinum 2 plugs, will I be sorry? Do I just take two bolts out of coil pack and push away to reach back plugs? Also have a faint smell of anti freeze , cannot find. Seems to smell at water pump area. Very slow leak, no moisture . Have had car for two years , and added just a little once. Thanks , LARRY . PS, I HAVE A 1996 NORTHSTAR DEVILLE Link to comment Share on other sites More sharing options...
JasonA Posted February 22, 2005 Report Share Posted February 22, 2005 If you haven't installed them yet, I'd take 'em back. AC-Delco dual platinum plugs are correct for your car, and will run best in the vast majority of the cars out there. Folks have had good and bad experiences with Bosch equipment. Personally, there ain't a thing that says Bosch on any of my cars, unless it was validated and spec'd by the factory. And that includes spark plugs, O2 sensors, etc. When I changed my spark plug wires, I did not remove the coil pack, or it's bracket. I have not changed plugs, so I cannot tell you if it's possible to do so without removing the coils, but I'd say it is. It was relatively easy to change the wires without removing the coils, and it didn't look like much more trouble to replace those rear plugs. I plan to finally do mine soon (they have 142,000 miles on them), but haven't done it yet. Jason(2001 STS, White Diamond) "When you turn your car on...does it return the favor?" Link to comment Share on other sites More sharing options...
Scotty Posted February 22, 2005 Report Share Posted February 22, 2005 If you haven't installed them yet, I'd take 'em back. AC-Delco dual platinum plugs are correct for your car, and will run best in the vast majority of the cars out there. Folks have had good and bad experiences with Bosch equipment. Personally, there ain't a thing that says Bosch on any of my cars, unless it was validated and spec'd by the factory. And that includes spark plugs, O2 sensors, etc. When I changed my spark plug wires, I did not remove the coil pack, or it's bracket. I have not changed plugs, so I cannot tell you if it's possible to do so without removing the coils, but I'd say it is. It was relatively easy to change the wires without removing the coils, and it didn't look like much more trouble to replace those rear plugs. I plan to finally do mine soon (they have 142,000 miles on them), but haven't done it yet. Ditto This was recently posted by our resident expert bbobynski, another reason I would stick with AC DELCO plugs: "The OEM spark plugs for the Northstar have nickel plated threads on the shell to minimize the chances of "galvanic corrosion" between the dissimilar metals causing a problem. Plugs rarely give a problem quite honestly. Most problems experienced in removing plugs occur due to overtorqueing the plugs at the last installation". Link to comment Share on other sites More sharing options...
Ranger Posted February 22, 2005 Report Share Posted February 22, 2005 No need to remove the coils pack. A plug socket on a 6" extention will work just fine. It's much easier than it looks. Link to comment Share on other sites More sharing options...
Barry94 Posted February 22, 2005 Report Share Posted February 22, 2005 I have replaced my plugs twice. The original Delco Platinums failed early. ALL the platinum contacts came off the ground electrode by 50K mi. I installed Bosch, they worked fine, however also had premature wear on the center electrode. I then installed NGK Platinum and they have worked very well. I check a few every year and they are lasting well. I find it easier changing plugs to detach the coil pack from the valve cover. I remove all the electrical connectors and leave the plug wires attached and flip the pack out of the way. Barry 2008 STS V82016 Colorado Z711970 Corvette LT-1 Coupe Link to comment Share on other sites More sharing options...
Scotty Posted February 22, 2005 Report Share Posted February 22, 2005 I have replaced my plugs twice. The original Delco Platinums failed early. ALL the platinum contacts came off the ground electrode by 50K mi. I installed Bosch, they worked fine, however also had premature wear on the center electrode. I then installed NGK Platinum and they have worked very well. I check a few every year and they are lasting well. I find it easier changing plugs to detach the coil pack from the valve cover. I remove all the electrical connectors and leave the plug wires attached and flip the pack out of the way. Barry Barry, when you replaced the plugs did you feel any discernable difference in the engine (power, idle, smoothness). I only have 67K miles but I am sure that I am going to find some of the pads off. They were off my 2002 Monte Carlo. I think I am going to pull my plugs and look them over. However I am concerned that if I pull them reinstalling them could cause a problem with the anti-cease properties, maybe its best to just replace them. I think its funny how years ago you would make this decision in the blink of an eye but today plugs never need changing. I have to think that a 96 with 67K miles has to have had a few fo the platinum pads come off by now.. Link to comment Share on other sites More sharing options...
JasonA Posted February 22, 2005 Report Share Posted February 22, 2005 I think its funny how years ago you would make this decision in the blink of an eye but today plugs never need changing. I have to think that a 96 with 67K miles has to have had a few fo the platinum pads come off by now.. Bah! Mine have 142k miles on them and the car still spanks the pants off most anything that I attempt to race. Pads...schmads. The only reason I'm planning to change mine soon is because of a cold rough idle that didn't go away with the new wires. I figure after almost 150,000 miles, these plugs could use a break. As you might say, "they don't owe me a dime!" Jason(2001 STS, White Diamond) "When you turn your car on...does it return the favor?" Link to comment Share on other sites More sharing options...
Mark Grek Posted February 22, 2005 Report Share Posted February 22, 2005 Just remember to use Ac Delco wires, other wise you will run into problems. Happened to a friend of mine. Link to comment Share on other sites More sharing options...
Scotty Posted February 23, 2005 Report Share Posted February 23, 2005 I think its funny how years ago you would make this decision in the blink of an eye but today plugs never need changing. I have to think that a 96 with 67K miles has to have had a few fo the platinum pads come off by now.. Bah! Mine have 142k miles on them and the car still spanks the pants off most anything that I attempt to race. Pads...schmads. The only reason I'm planning to change mine soon is because of a cold rough idle that didn't go away with the new wires. I figure after almost 150,000 miles, these plugs could use a break. As you might say, "they don't owe me a dime!" Hold on, I'll send you mine! Link to comment Share on other sites More sharing options...
growe3 Posted February 23, 2005 Report Share Posted February 23, 2005 As others have noted it is not necessary to remove the coil pack to R&R the rear spark plugs. I would recommend using ½’ drive extension with flex joint if you have them. The ½” drive is much stiffer and will break loose any spark plug easily. Use a 3/8” drive setup when you put them back in, to avoid over tightening them Regarding Bosch plugs, I am sure someone has had success in some engines with them, but I would not recommend them for the Northstar based on my personal bad experience with them, in both of my 93' STS's. I used the Bosch Platinum 4 type. They appeared to burn clean, but I would have a little bit of roughness in the idle, and the engine just did not feel up to par when accelerating. I put them in shortly before a smog check and while I passed, the HC reading were on the high side. I changed out the plugs a week later and talked the guy into giving me a quick reading. The car was well into normal (low) emissions again. I tried the same plugs on my other car and the same results. I don't know why they do not perform as they should but....... I use Champion dual platinum and so far no problem after 50,000 miles or so. In my other car I use AC Delco spark plugs and no problem. Check the AC Delco web site for the current part number for your car. -George Drive'em like you own 'em. - ....................04 DTS............................ Link to comment Share on other sites More sharing options...
Regis Posted February 23, 2005 Report Share Posted February 23, 2005 Still have my bosch platinum plugs in. I guess this would be the start of the 3rd year with them. Seems to work just fine. I do have an 8pak of delco platinums on the ready just in case. Today I was out getting more oil and a filter for the LOF this sunday. I have to say that I actually went out of my way to purchase a delco oil filter..... just for laughs and giggles. Hey it's a first for me but i wanted to give it a whirl. "Burns" rubber " I've never considered myself to be all that conservative, but it seems the more liberal some people get the more conservative I become. " Link to comment Share on other sites More sharing options...
jmsts Posted February 23, 2005 Report Share Posted February 23, 2005 i installed new ac delco double platnium plugs shortly after purchase of my 97 sts in sept 04.the car had 68000 mi. at the time, the plugs that i removed were in fair condition (ac delco) three of them were missing the platnium from the bottom electrode. the car runs much smoother now. i did move the coil pack out of the way from the rear bank of cylinders & that helped the process. i also put a touch of anti seize compound on the threads of plugs for easier removal next time. have a good week. Link to comment Share on other sites More sharing options...
rollingthunder1994 Posted February 23, 2005 Report Share Posted February 23, 2005 When i bought my 94 STS last April the previous owner said the plugs were just changed about 4-month prior. I've notice a slight hesitation and vibration for about a month. So i went to the auto shop and picked up new plug anyway AC Delco. When i took out the plugs, the previous owner had Bosh plugs installed, looking at the plugs they did not look bad at all, infact they looked faily new. Once i installed the AC plugs, started the car, No hesitation on acceleration, or engine vibration at all with 112,000 miles. I cannot speak for every NS, but for mine it is without a doubt asking for AC Delco. So now i know to use AC for everything with this particular motor. Solved one problem now another arises. If i only can solve overheat problem. Anyway AC is the way to go for this NS Link to comment Share on other sites More sharing options...
Barry94 Posted February 23, 2005 Report Share Posted February 23, 2005 Barry, when you replaced the plugs did you feel any discernable difference in the engine (power, idle, smoothness). I only have 67K miles but I am sure that I am going to find some of the pads off. They were off my 2002 Monte Carlo. I think I am going to pull my plugs and look them over. However I am concerned that if I pull them reinstalling them could cause a problem with the anti-cease properties, maybe its best to just replace them. I think its funny how years ago you would make this decision in the blink of an eye but today plugs never need changing. I have to think that a 96 with 67K miles has to have had a few fo the platinum pads come off by now.. Hi Scotty, I never really noticed any difference between all three brands. When I purchased the '94 (in'97) it ran quite rough at idle. That prompted the look at the plugs and I discovered the platinum pads missing. I installed Bosch, however I still had the rough idle. The rough idle was a burned exhaust valve. (55 lbs. compression on that cyl) After fixing the valve, it ran well on the Bosch. The problem was, the center electrode burned down fairly quickly. Thats when I switched to the NGK. The NGK's have been in there for 3-4 years now with no problems. The reason I didn't go with AC Delco was the short life of the original plugs. I hope the quality has improved over the years. Barry 2008 STS V82016 Colorado Z711970 Corvette LT-1 Coupe Link to comment Share on other sites More sharing options...
terrylange Posted February 23, 2005 Report Share Posted February 23, 2005 I changed my plugs this weekend in my '97 DeVille with 159,500 miles on it. I have no idea if they were the originals, but I know they have at least 55,000 on them. I did use OEM AC Delco plugs from Auto Zone. I removed the 4 bolts from the coil pack so that I could move it out of the way to have better access to the rear plugs. For the five minutes it took to remove the bolts that held the coil pack, I saved the aggravation of trying to work around the mass of plug wires. It also gave me the chance to look into the rear plug holes with a mirror to make sure there wasn't any debris that could fall into the port once the plug was removed. I seem to see a little more "pep" in the car after the plug change, but that could all be my imagination. I will check the mpg over the next couple of tanks to see if there is any increase in that figure. By the way, the job was easy, it took less than an hour to change all 8 plugs. So much for all the horror stories. Maybe I was just lucky!! Link to comment Share on other sites More sharing options...
JasonA Posted February 23, 2005 Report Share Posted February 23, 2005 I had a bad experience with Bosch plugs on my Nissan truck. The recommendation there is to ALWAYS use the OE plugs, in that case, NGK. As growe3 said, "regarding Bosch plugs, I am sure someone has had success in some engines with them." That's the chance you take with aftermarket plugs. Sometimes they'll work, sometimes they won't. Barry, I remember Bbobynski mentioning that sometime during the mid-to-late 1990s, they changed the adhesion process for the platinum pads which caused them to last a LOT longer than previous platinum plugs. Do you suspect you changed out the original 1993 platinum plugs when you first did yours? Jason(2001 STS, White Diamond) "When you turn your car on...does it return the favor?" Link to comment Share on other sites More sharing options...
Barry94 Posted February 23, 2005 Report Share Posted February 23, 2005 Barry, I remember Bbobynski mentioning that sometime during the mid-to-late 1990s, they changed the adhesion process for the platinum pads which caused them to last a LOT longer than previous platinum plugs. Do you suspect you changed out the original 1993 platinum plugs when you first did yours? I'm quite sure they were the original plugs. When I bought the car it only had 50K mi. I'm not sure I will ever use AC Delco plugs again. I'm sure the quality has improved on the AC plugs, however the NGK plugs cost 60% less and appear to work as well. I suspect the NGK plugs will not live as long as the AC plugs. If you have to pay someone to replace your plugs, then the AC plugs would likely be the best buy as they should last longer. Barry 2008 STS V82016 Colorado Z711970 Corvette LT-1 Coupe Link to comment Share on other sites More sharing options...
tmpafford Posted February 23, 2005 Report Share Posted February 23, 2005 I did a spark plug change on my 97 STS at around 75000 miles. Went with the AC Delco. Thought I would feel a difference in power. Felt none. Gas milage was the same. Last week I changed out the spark plug wires. Big difference! Felt like it had more power and ran smoother. I take a long trip every weekend and before the change I was getting 22.5 mpg. This past weekend I got 23.6 on a round trip to Little Rock from Houston. That was with the cruise control set at eighty most of the way. I also did a WOT as described in a post last week before the wire change. Little cloud of crud came out. Did another WOT after the wire change and big cloud of crud came out. Did it a third time after my trip to Little Rock and nothing came out. My theory is that I had one cylinder getting a bad spark and was not burning the crud and fuel very well. Link to comment Share on other sites More sharing options...
james thomas smith Posted February 23, 2005 Report Share Posted February 23, 2005 Solved one problem now another arises. If i only can solve overheat problem. Anyway AC is the way to go for this NS Why don't you try some timeserts in your engine, maybe that will work. Link to comment Share on other sites More sharing options...
JasonA Posted February 23, 2005 Report Share Posted February 23, 2005 Solved one problem now another arises. If i only can solve overheat problem. Anyway AC is the way to go for this NS Why don't you try some timeserts in your engine, maybe that will work. You're absolutely right -- if the headgaskets have failed, the only proper repair is to include Timeserts with the new headbolts. Jason(2001 STS, White Diamond) "When you turn your car on...does it return the favor?" Link to comment Share on other sites More sharing options...
Regis Posted February 27, 2005 Report Share Posted February 27, 2005 Well today Dave and I took out the bosch supers and installed the delco platinums. Big difference at WOT. I haven't seen the tach swing that far right in some time. Otherwise everything else seemed normal. Still have the snow tires on so it was only a 2 WOT day. "Burns" rubber " I've never considered myself to be all that conservative, but it seems the more liberal some people get the more conservative I become. " Link to comment Share on other sites More sharing options...
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