3800 series III plugs/wires

[jwbouch]

I'm quickly approaching 100K miles. I was planning to do spark plugs and wires at 100k. First off, that is when I'm supposed to do them right? Second, any good suggestions for reaching those plugs on the back bank? Any other preventative maintenance things that should be getting done around 100k? Thanks everyone!

[SAmadei]

I'm quickly approaching 100K miles. I was planning to do spark plugs and wires at 100k. First off, that is when I'm supposed to do them right? Second, any good suggestions for reaching those plugs on the back bank? Any other preventative maintenance things that should be getting done around 100k? Thanks everyone!

I would do them when they are over 100K or if you have a misfire problem going on. My plugs got replaced for the first time around 196K on my Series II, but the wires only lasted until 50K, and were replaced by the dealer selling me the car, trying to chase a misfire. When I replaced the plugs at 196K, they looked brand new... I imagine I could have ran them _much_ longer...

I imagine the GP is a bit tighter than my Bonne, but reaching the rear plugs isn't too bad, if you have long arms. I would recommend standing on a 6" stool or block at the minimum, it gave me much a much better angle and reach. There will be a engine lift bracket held onto the rear exhaust manifold held on with two nuts... removing/loosening that can give you some room. Keeping in mind that the rear plugs are angled towards the passenger side, IIRC, which will help you grope around before you put the socket on... IIRC the one close to the PS pump is the worst to get to.

On my car, the plug wires were pretty badly stuck to the plugs (a big part of why I need 95K extra miles to replace them... LOL)... so I had to cut and mutilate my plug boots to get access to the plugs. Make sure you use good wires with lube/antistick on the plug boots.

Due to the odd angles, its easy to break a plug... so you need to ensure the socket is properly engaged on the plug. Sometimes I buy 7 plugs in case I break one... and take it back if successful... Speaking of breakage, the front plastic harness will likely be brittle, so be VERY careful removing/replacing the wires in it. IIRC, its only available at the dealer, and not really cheap.

Good luck.

[loki]

it's recommended to get the tranny fluid and filter changed every 100K no matter what... right? did mine at ~150K don't know if wear on the brass parts was normal since it was the first time i know it was done...the shop said the filter had alot of brass in it... could be normal if that was the first time.

[jwbouch]

it's recommended to get the tranny fluid and filter changed every 100K no matter what... right? did mine at ~150K don't know if wear on the brass parts was normal since it was the first time i know it was done...the shop said the filter had alot of brass in it... could be normal if that was the first time.

I did my tranny fluid/filter at 50, and will do it again at 100. My brother had an 02 Impala that blew a tranny at 120k - I would like to avoid that at all costs!!!! I had a transmission shop (friend of the family) do it, because I had never done one at that point, and didn't realize how easy it is (since I have access to a lift). The mechanic said it wasn't bad, but he wanted to do it again in 10k miles anyhow. So it actually got done at 50 and 60. I'll do it at 100, then probably never worry about it again. I have a bad habit of trading in my car the same day I send in the last payment.

I would do them when they are over 100K or if you have a misfire problem going on. My plugs got replaced for the first time around 196K on my Series II, but the wires only lasted until 50K, and were replaced by the dealer selling me the car, trying to chase a misfire. When I replaced the plugs at 196K, they looked brand new... I imagine I could have ran them _much_ longer...

I imagine the GP is a bit tighter than my Bonne, but reaching the rear plugs isn't too bad, if you have long arms. I would recommend standing on a 6" stool or block at the minimum, it gave me much a much better angle and reach. There will be a engine lift bracket held onto the rear exhaust manifold held on with two nuts... removing/loosening that can give you some room. Keeping in mind that the rear plugs are angled towards the passenger side, IIRC, which will help you grope around before you put the socket on... IIRC the one close to the PS pump is the worst to get to.

On my car, the plug wires were pretty badly stuck to the plugs (a big part of why I need 95K extra miles to replace them... LOL)... so I had to cut and mutilate my plug boots to get access to the plugs. Make sure you use good wires with lube/antistick on the plug boots.

Due to the odd angles, its easy to break a plug... so you need to ensure the socket is properly engaged on the plug. Sometimes I buy 7 plugs in case I break one... and take it back if successful... Speaking of breakage, the front plastic harness will likely be brittle, so be VERY careful removing/replacing the wires in it. IIRC, its only available at the dealer, and not really cheap.

Good luck.

My car actually runs really well still - in fact last weekend I drove from NJ to Ohio for a niece's graduation party - and I got the best fuel mileage I've ever gotten. I was just going to do it because I thought I was supposed to at 100k.

So, just to demonstrate that I'm not as fluent as I'd like to be.... what is IIRC?

Thanks for all the advice!

[SAmadei]

So, just to demonstrate that I'm not as fluent as I'd like to be.... what is IIRC?

'If I recall correctly'.

I don't advocate letting it drag well beyond 100K mileage... but, for me, as long as there is not an immediate problem, things like changing the fluids are far more important.

I do, however, advocate using quality parts when you do, as modern cars seem much more sensitive to misfire.

[fightingbee]

If the '04 still has the second hole on one of the engine mounts at the upper radiator support to hold the engine tilted forward a bit, there should be decent access room, much more so than some other FWD V-6s at least.

You could still tilt the engine on a '99 I know, but have not replaced plugs on any W-car newer than that.

[jwbouch]

So, I changed my plugs/wires a few weeks ago. No problems what so ever. I didn't have to tilt the engine or anything. Just reached back in there and took care of it! Thanks for the advice though! I appreciate it!!!

[@dmin]

I hate to bring up a dead thread,but its relevant to a series 2 3800.

When replacing spark plugs should I stay with Delco's or go aftermarket like NGK. I have heard to avoid platinums as they are just a marketing ploy and tend to foul quickly on lower compression engines.

[fightingbee]

FWIW, the new AC plugs for both my 3800 Camaro and my mother's Regal were actually NGK-made Iridium plugs, just with different box/labeling on the insulator. There were NGK markings on the metal shank of the plugs. IIRC, the AC plugs on my 2.2 Ecotec Saturn were the same way when I bought them.

I think the actual AC Spark Plug plant in Flint was shut down awhile back.

[Drew Dowdell]

I just bought a set of iridiums for my 307 and it made a big difference. They replaced a set of A/C Delco platinums

[@dmin]

In a related note how long do the coil packs last in a 98 series 2 3800?

[SAmadei]

In a related note how long do the coil packs last in a 98 series 2 3800?

It depends. They can be tested easily enough with a Ohm meter. My '99 Bonne has 229K and they are all original... the '99 GP has 100K and already had a dead one swapped out. They can be changed independently.

They seem to hold up pretty well.