36,000 mile service?

Science_Guy · **Posted:** Sun Oct 08, 2006 7:47 pm

I just hit 36,000 miles on my 2004 Liberty. I read somewhere at 36,000 I should change the spark plugs. Is this a good idea? What would be a good brand to buy? How hard is this to do (say compared to changing the oil)?

I also was told at Autozone I should add a fuel injector cleaner to my gas tank every time I change the oil (about every 3 months or 3,000 miles). Was this them just trying to sell me something or is there something to it?

Thanks

Jeepjeepster · **Posted:** Sun Oct 08, 2006 8:10 pm

I usually add some valvoline fuel injector cleaner every oil change. They have two different kinds though. One you use everyother change and one you use every oil change. One is more expensive than the other one though. The more expensive one is the one you use less often.

Its a god idea to change the plugs at 36k. Thats probably when ill change mine as ive heard they wear kinda quick. Autolites are good. NGK is what alot or people use too. Dont get anything thats expensive, its bull and usually hurts the libbys performance.

KY Liberty · **Joined:** Sat Jul 09, 2005 1:46 pm **Posts:** 1195

According to the manual, at 36k you need to change the oil and filter. Inspect ball joints. Inspect brake linings, and change the fluid in the diffs. It also recommends at 30k to change the transmission fluid and sump filter, and inspect and replace the PCV valve if needed, check the air filter, and replace the spark plugs.

Your spark plugs will probably be worn to around .060 with 30k miles on it. They really should be replaced. The factory NGK ZFR6F-11G typically work fine. You should check your plugs to make sure you're not running really rich or lean, or too hot, and to make sure you don't have any coolant leaking. Typically happens between the front 2 cylinders on the passenger side.

KJTom · **Joined:** Thu Nov 03, 2005 8:37 pm **Posts:** 18

I changed my plugs at 22K because it seemed to be idling a little rough. The plugs didn’t look too worn when they came out; the plug change didn’t make much of a difference either so I’m just going to blame the rough idle on the 6-speed setup. Either way, it can’t hurt and it is about time according to the service schedule. It’s not difficult and it only took about an hour. If you have a decent ratchet set with some universals, you won’t even have to remove the air hose or coolant reservoir. For $15 - $20, get the NGK plugs (and a receipt for your records) at the dealer. The coil-on-plug setup is very easy to work with.

chetos · **Posted:** Mon Oct 09, 2006 10:32 am

I changed my plugs @ 25000 and they were very well worn.

raceinfan · **Posted:** Mon Oct 09, 2006 11:38 am

I did mine at just about 28,000 & noticed a big differance with the new ones even though they are OEM & had all my fluids serviced the week after you can go by the manual but I'm used to doing it around 30,000

desertkj · **Joined:** Mon Jan 30, 2006 8:24 pm **Posts:** 677

I think it was around 30000 that we replaced my spark plugs with some Bosch Platinums and it made a good improvement. As far as fuel injector cleaner, I usually put in the the Techron stuff every 1500 miles (its kind of expensive usually, but they sell a four pack at Costco).

36,000 mile service?

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