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DENSO or AC Delco Spark Plugs for a Northstar?

24K views 33 replies 9 participants last post by  GreenMachine  
#1 ·
I have a 2000 Deville and I am changing the plugs, I was surprised to find the Denso brand as factory installed plugs. My car has 90K miles and I am doing a Major tune-up. Filters oils plugs, even the Thermostat, any suggestions?
I live in Austin Texas and autozone and partsamerica have Denso and Ac Delco brand, but I dont knot which one to get, also, would you recommed ac delco for the thermostate and the filters?
anysuggestions would be greatly appreciated.

Gerardo.
 
#2 ·
Everything I've seen here (and elsewhere) seems confirming the thought BUY ONLY GENUINE AC DELCO parts for the Caddy - no other brands are tested and certified to the rigorous standards.
 
#4 ·
It really doesn't matter. Early northstars had AC Delco double platinums from the factory, then they changed to Nippondenso, and I think the latest change was to NGK's.

Buy whatever you want, as long as it's one of the above brands, you'll be fine.

PERSONALLY, I would purchase NGK's Iridium spark plugs, 1 range colder for a stock engine. If you plan on doing any racing or performance mods, 2 ranges colder. You will need to keep up on the WOT's, because you'll have a higher chance of fouling the plugs if you don't.
 
#5 ·
I just finished Installing the new spark plugs, It is weird, that the Denso plugs are just the same as the Acdelco, same blue stripe and both of them have the letters made in japan and xxxxx about 5 or x's, I think they are the same, So I just installed them yesterday at 11:00 PM I was Done, I changed the thermostat, cabin air filter, PCV and I will put a new Fuel filter today, by the way, the inside of the cap of the thermostate was very rusted, my brother used the car about 6 months without the Dexcool coolant, he just used water and it looks pretty bad from the inside, so I will run a Preston Cleaner today and tomorrow I will pour 2 gallons of ac delco dexcool coolant, by the way.. it costs 21 dollars a gallon :S kinda expensive..

Ger

'00 Cadillac Deville-sedan.
 
#7 ·
.... the inside of the cap of the thermostate was very rusted, my brother used the car about 6 months without the Dexcool coolant, he just used water and it looks pretty bad from the inside, so I will run a Preston Cleaner today and tomorrow I will pour 2 gallons of ac delco dexcool coolant, by the way.. it costs 21 dollars a gallon :S kinda expensive..

Ger

'00 Cadillac Deville-sedan.
Couple of things don't add up here. Ninety percent of your cooling system is aluminum and another 5% is rubber. Where is the 'rust' coming from? Or is it really something else?

Who uses straight water? There is a chance the engine has reached temperatures that would vaporize straight water even under 15 pounds pressure.

Dex-Cool is produced by ChevronTexaco's Havoline brand and is $8.00 per gallon at Wal-Mart. Add a gallon of $0.97 distilled water and you have 2 gallons of 50/50 mixture anti-freeze for less than $10.00.

Add a couple of tubes of Bars Leaks Golden Seal powdered material just as insurance against nuisance leaks.

And remove that Prestone cleaner as soon as you can.
 
#9 ·
It is actually not rust.. it is most like, humm at first it is sticky orange colored, and when it dries turns white, kinda hard to explain, I will buy the preston dexcool from walmart ($9), and one more question, do I have to add that couple of tubes of Bars Leaks Golden Seal powdered material in a 2000?

Thank you.

Gerardo.
 
#10 ·
You don't have to add anything. The Bars Leaks is cheap insurance; in fact what you thought was rust "could be" the same material as Bars Leaks that was added with the factory fill and it just dropped out of solution.

GM stopped putting the material in the factory fill at some point because drivers were seeing what you saw and thought there was a problem. But I don't remember the exact year.
 
#11 ·
The orange coloured liquid is in fact Dexcool.
As JimD stated, all you need to do is add the Bars Leak (coolant suppliment).

Then again,it may be a good idea to do a complete coolant change, if your brother was having to top up with water,this means the Dexcool has become over diluted and is no longer 50/50.

Do a search on the subject, there's tons of info on this site.
 
#13 ·
hahaah #1 I already did
#2 Done.

Today, finally I will puor a gallon of dexcool, since I am just getting a nut alike piece of plastic from under the radiator to get some of the water out, I already flushed and filled with clean drinkable water the radiator 3 times, so now I know that there will be fresh water in the block and heater core, today i will go to the autoparts looking for the bars leak, and puor 1 of the 2 gallons of Prestone dexcool that I bought for this vehicle.
Thank you very much for all your replys.

Gerardo.
 
#15 ·
Yeap. there was a leak right in the place where the thermostate is, it was not that big, but he needed to add almost a gallon every 3 days to keep up with the leak, so after 2 - 3 months, there was only water in the system.
By the way, I was so scared today, I flushed the system for the last time before adding the coolant, and then I poured the coolant, only 1 gallon was enoguh to bring it to the level, but after driving it for 5 minutes with the weather at 107 (in Austin TX) there was a messege in the dash (ENGINE HOT, AC OFF) It scared the crap out of me, I parked it and let it idle for about 3 minutes until it was at the middle (The gauge) then when it cooled I had to add another gallon, this one was 50-50 water dexcool. so now there is about 70%dexcool and 30% destilled water.
just wanted to share my day.

greetings.

Gerardo.
 
#16 ·
Keep an eye on the level in the reservoir. You want about two inches of air space when the engine is cold.

You might find that your "heavy" mixture of antifreeze does not conduct heat as well as the desired 50/50 mix. Easy enough to adjust by draining and refilling a few times with a 50/50 mix.
 
#19 ·
Do not put any liquid Bar's Leaks products in there.

Use the Bar's Leaks Golden Seal radiator stop leak powder (product G12BP on the bottom left hand corner of the package) which is usually available at Wal-Mart or the same material in a package of big old tablets.

And put the powder or tablet in a hose, NOT the reservoir.
 
#26 ·
If you happen to use the GM supplement tablets, DO NOT CRUSH, but add whole to the LOWER radiator hose.

I crushed the tabs added to the top hose (it was easier and I was lazy).

Fouled the T-stat all to hell and the rest settled in the left side radiator tank. Over heated in 15 minutes. My radiator guy laughed at my not heeding to the information on my forums board and added, "thats what you get for being lazy and not letting me do it! He's a friend so I had to take the chastising and insult).
 
#30 · (Edited)
picture of my coolant/oil change day products:
Image

(FRAM filter promply was returned after reading bad stories about them)

I used quickfill since I basically blew all the contents of dexcool out of my system and simple refilled, all in all I ended up replaceing nearly all of it.

on the plugs I have a question, does AC Delco outsource and then rebadge the plugs? Or make the plugs themselves? I'm curious because I'm not really a fan of putting in parts made elsewhere when I can get plugs that are made in the US.

useful links:
Counterfeit Auto Parts | ACDelco
ACDelco’s Role Combating Counterfeit Auto Parts | ACDelco