Changing Plugs on a 1999 3.8 LTZ

[Corndog Man]

I never thought I would have trouble getting the wires oof but they have a metal tube with the wire inside the tube. I tried to pull and twist but to no avail. Is there a tool to pull these things off. Am I going to have to tilt the engine to get to the back three? Has anyone done this on a 3.8?

[MarkNYC]

I just changed the plugs and wires on my '98 3.8L LTZ and have the forearm bruises to prove it. The front three came off very easily, but the rear three were an exercise in anger management. I almost gave up, but went to Autozone and bought a boot puller, and a correct universal joint type of spark plug wrench, which helped somewhat.

I put in Bosch Double Platinum plugs and Bosch Premium Wires. The car started and runs smoothly. There were some plastic wire covers made of crinkly plastic and I'm not sure if they need to be put back on. I can't imagine that the plastic tubes helps to protect them against heat, so I'm wondering if they are even necessary to put back.

Good luck, man!

[Corndog Man]

Thanks Mark. I will give that a try. These tubes look like metal insulators around the boots. I thought I wouldn't have any trouble getting them off. These are on the front mind you. No way as of yet.

I have been reading about tilting the engine. I don't know if anyone has done this on the 3800. I looked at it and seems that removing the dog bones and tilting forward wouldn't work. Looks liek I would have to unbolt the exhaust and everything else. I guess my thinking is flawed.

I bought the AC Delco platimun tipped plugs like what was in it. I then to go AC Delco on all of the parts I buy. I am thinking these plugs will help but won't fix my problem with the hard starting. Don't want to go to the dealer until I get this stuff changed.

[jeffcoslacker]

I always spray WD-40 on the boots in advance, then start by twisting the boot slightly both ways until it breaks the cheez that holds it on. Then they usually come off pretty easily. If they come apart...I tell myself they needed replacing if they are that crappy. I can't remember any reason why you couldn't tip the 3.8 same as any other. Doesn't it have the roll restrictors on top like the 3.1?

[jeffcoslacker]

If you replace the wires, be sure to route them the same as OE. Sometimes they can throw an inductive signal that sensor wiring picks up, and cause some strange glitches.

[Corndog Man]

Thanks Jeff,

I am not very familiar with the 3.8. I have done some fuel system work on my Astro with the 4.3. Spider valve replacement and such. I just haven't messed with any FWD before. Pulling the engine forward sounds strange without doing anymore than releasing the dogbones. Oh well. I am always up for a challenge.

I thought the Haynes would tell me what to do and show a photo or two.

I know my problem isn't the plugs but with 95K, I thought I'd go ahead and replace.

My problem almost seems like there is a pressure problem on start up. I need to put a gauge on the fuel runner and see if I have a leak down somewhere. Maybe an injector is leaking down or there is a pressure switch. Anyway, it runs fine but I know something is going to give out on it.

This LTZ is a great little car. My only problems have been wtih the Sun Roof which I have yet to correct and the turn signals in the column. I used to get some shudder in the tranny but I changed the fluid a few times and used an additive the last time. I don't remember what it was but I haven't had the shudder since.

[Kooterskkar]

There were some plastic wire covers made of crinkly plastic and I'm not sure if they need to be put back on. I can't imagine that the plastic tubes helps to protect them against heat, so I'm wondering if they are even necessary to put back.

It keeps the wires away from the metal parts of the engine and protects against cuts and things of that nature. Those wires carry a very large amount of electricity which can jump the insualtion and short if it is near any sensors or other plug wires. When it does that you get a misfire.

[jeffcoslacker]

Originally Posted by Corndog Man

Thanks Jeff,

I am not very familiar with the 3.8. I have done some fuel system work on my Astro with the 4.3. Spider valve replacement and such. I just haven't messed with any FWD before. Pulling the engine forward sounds strange without doing anymore than releasing the dogbones. Oh well. I am always up for a challenge.

.

These motors just kinda teeter on the mounts, the restrictors keep 'em from pitching too much. The exhaust has very slinky joints to allow for movement. If you put the car in park and rock it back and forth, you'll be suprised how much movement is there, even with the restrictors in place. That's how I tip the motor. I take the bones off, rock it against park until it heaves over forward real far, and stomp the E-brake, freezing the motor in that position. Block a wheel so it can't creep and let the motor drop, and you're set. Use a ratcheting tie down to crank it forward if you aren't comfortable with this.

[Manny_boy]

...remember to put di-electric tune-up grease inside of the spark plug boot... it keeps the boot from seizing to the plug due to high engine temps and aids in removal next time...

[PoliceCarToTaxiCab]

I have a 99 chevy Lumina 3.8. I had my mechanic buddy pick me up a "Dog Bone" tool from the Snap-On guy for about $40. This thing has come in handy for jobs like changing the rear plugs, front oxygen sensor and just about anything else behind the engine. This is a must have tool! You just remove the bolts from either engine strut, install the dog bone tool, remove the bolts from the remaining engine strut and tilt the engine forward. The tool specifies that the engine should be in neutral when doing this. When I changed my plugs, I removed the metal plug wire heat shields (which by the way, was a pain in the rear...but a little careful twisting and some patience will go a long way) and left them off. I haven't had any problems so far.