Anyone change plugs on their Montana?...

[rubberman]

Thinking about changing the spark plugs and possibly the belt. I was wondering for those who did change the plugs, how did yoou reach the back cylinders? Since the motor is stuffed back in there it looks rough on getting access to those plugs and even trying the change the belt looks rough.

[Flatrater]

The belt is easy to change but the plugs are a killer.

I have changed plugs but I have a lift to do it on and it is still hard to do.

[ced_snyder]

Originally Posted by rubberman

Thinking about changing the spark plugs and possibly the belt. I was wondering for those who did change the plugs, how did yoou reach the back cylinders? Since the motor is stuffed back in there it looks rough on getting access to those plugs and even trying the change the belt looks rough.

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I did both of these chores on my '99 Montana at 100k miles. If you don't have this many miles on the van, I'd recommending waiting ... the platinum plugs installed at the factory will last 100k miles with no problem.

Changing the belt is a piece of cake. Just get a 3/8" ratchet, plug it into the square hole in the lower portion of the tensioner pulley (below the alternator), and lift up on the spring-loaded tensioner. The belt can be easily slipped off the power steering pulley (which is easy to get to since it's right under your nose as you lift on the ratchet). The routing for the new belt is posted on a plastic tab below the power steering unit, so you can't go wrong. By the way, you'll be a lot happier if the engine is completely cool before you mess with it. Replacing the belt takes about a minute. [I stuck my old belt in the storage bin with the jack "just in case".]

The spark plugs are another matter -- replacing the rear plugs is not for the faint of heart. As an aside, I strongly recommend spending the extra bucks for the Bosch Platinum Plus-4 plugs; they'll probably last longer than the van if you're changing plugs at 100k miles.

OK -- the front 3 plugs are obvious. I won't bother to give anything but a bit of advice: when you pick up your plugs, get a little squeeze packet of dielectric grease (so the spark plug wire boot can be easily removed in the future by whomever has to screw with the plugs again) and a little squeeze packet of non-seizing grease for the spark plug threads (same reason). These packets are available at your local parts store for under a buck. Last bit of advice ... GM didn't use anti-seize grease on the plugs at the factory; it takes a bit of torque to break the rust on the old plugs. Replacing the front 3 plugs takes 3 to 5 minutes.

Now the nasty part -- replacing the rear 3 plugs (which you can't even see). Actually, it's not too terrible, but certainly not straightforward. The trick is that you have to rotate the engine foward a bit for access to the portion of the engine close to the firewall. You'll need a ratcheting nylon strap (which you can always use for holding down loads on your top rack) -- they're available at any auto parts store or WalMart or wherever. Here's how to get acess to those damn rear 3 plugs ...

1. If your engine has a plastic shield over the intake manifold (some engines do, some don't), remove it by twisting off the tube and oil fill cap from the front rocker cover, then lift the cover up and towards you. Replace the tube/oil fill cap so you don't knock anything in. This job takes about 30 seconds.

2. Remove the black plastic cover over the windshield wiper motor -- first lift off the long rubber gasket at the base of the windshield; then lift up on the wiper cover (you might have to push up on the little clips with a flat-blade screwdriver). This job takes about 30 seconds.

3. Remove the air duct from the throttle body to the air filter. As you have probably already found out, just checking the air filter is a bitch on the Montana. I remove the coolant tank (1 bolt) and set it on the engine; then I remove that black brace (3 bolts); then I unplug the square electrical connector to the Mass Air Flow sensor; then I loosen all the hose clamps on the air ducts; then I shake, pull and cuss till the damn thing comes apart so I can look at the air filter. Anyway, do this and set the air duct aside. This seems to take forever, but it's probably less than 5 minutes.

4. Now you rotate the engine forward for some access room between the engine and the firewall. First, set the parking brake and shift into neutral. Remove the black Y-shaped motor mounts that go from the top of the engine to the brace above the radiator (takes less than a minute). Hook the ratchet side of the strap to the black ring bolted to the top of the engine; then hook the long side of the strap to the frame under the bumper; thread the strap, ratchet it tight, and watch the engine rotate forward 3 or 4 inches. Damn! That was surprisingly easy.

5. According to GM, you now have access to the rear plugs. HAH! I think I barked knuckles and strained and sweated for about an hour and a half (from above and below the engine) before I finally replaced the plugs. The basic problems are (1) the wire boots don't want to come off (GM didn't use dielectric grease) and you have no leverage nor working room, and (2) similar problem with the plugs that were installed by GM without anti-seize grease. A decent collection of socket extensions will be handy, too.

6. The reverse of the above procedures puts the van back together -- it seemed to be a lot quicker putting it back together than it did to get to the point of the rotated engine, but that's probably because I had an inkling of what I was doing by then.


Though the above description sounds awful, it was accomplished in an afternoon (but I was NOT a happy camper at the end of the day). If you don't want to try this yourself, consider having a GM shop do it (at their exorbitant rates) rather than a local mechanic (who probably has never messed with a van like the Montana). At least have the courtesy to show this document to the local mechanic before the task -- he might want to duck and run.

Good luck.

[rubberman]

Nice work and very good detail. The engine has 52k on it so i might wait. Just by looking at the belt it looks to be a b!itch to do since the tensioner is down towards the bottom and the coolant bottle is smacked up by it. thanks again.

[rcompson]

My Montana 2000 has 54,294 miles on it and I wanted to have the timing belt changed but cannot find anywhere of how many miles to change the timing belt on the Montana. Any ideas?
Rob in MD

[Flatrater]

Gm does not use timing belts in this engine they use chains which do not require replacement.

ced_snyder
One thing to add your your post if you put the trans in neutral with the parking brake on it will make rotating the engine forward easier.

[Dthane]

Where do you hook the strap to, I know it's the eyelet or hook on the top, but do we come around just in front of the radiator/ac and hook on the frame? I don't want to hurt or bend anything I'm not supposed to. The total distance that we could "move" the engine with the air intake removed was only about 4-5 inches. Once you do that, and get it "set", is it easier to "attack" from the top/back or from underneath?
Also, I could only be in neutral with the key in and in the on (not start) position. That won't be drainging my battery will it, and if so, would you recommend any other option electrically.
The dealer told me they make something that looks like an A frame that can also be used to "move" the engine forward, but I'm going to be the strap is alot cheaper. Thanks for the info.

[gadan]

I'm ready to replace the spark plugs, should I also replace the spark plug wires? If so, which brand should I buy.
Thanx in advance.

[rubberman]

wires its recommended to put some AC Delcos backon there. Best replacement.

[montana99]

I was able to change the plugs by just removing the spark plug modules at the aft of the engine.It is then possible to reach back. Hope this helps speed up the process

[shogunl]

Well I changed my plugs "Twice" because I used Bosch plug. Second time I put in NGK platiniums.
Like mentioned above it takes 15 minutes for the front 3 and about 4 hours of work and lots of cursing and swearing for the back 3.

[gkindub]

I would not wait too long to change those plugs because the chances of one getting stuck increases over time. I changed mine at 67K and noted that the gaps were way over .060 and even eroding on two plugs.

In ced_snyder's very nicely detailed instruction write-up he did not mention removing the ignition module. You will find things "easier" to access on the backside of the engine by removing this. You will need at
least a 4 hr block of time to complete this job. Good luck.
Shogunl, why did you remove the Bosch plugs and switch to NGK???

[shogunl]

Bosch plugs causes ignition problem. There are lots of threads warning not to use bosch plugs. I found this after I puts bosch in. after 30000 km(20000 mi) it started to miss and caused fault in the OBD II.
They say to use AC delco but I figure I would try NGK, If NGK causes problem I would have to use AC Delco, but I would be really pissed at myself for doing the #@%**# thing the third time.

[catesja]

I don't think I will ever do that again!!! It took about 8 hours to do a tune-up to my van. It took about 3 hours to squeeze my hand and socket into the hole to remove the rear left coil pack nut. Needless to say, I left that one off when I put it back together! Then plug 4 and 6 both broke the boots off and the clip. I had to cut the boot and strip it off the plug. (Number 6 is harder than the back 3) So I had to get a new set of wires but I didn't want/have the urge to pull the van all back apart to replace them all, so just the 2 broken ones where replaced. hopefully I won't have to do it again for 100,000 miles! I did get Bosch and then returned those to get the AC Delco as I heard about not using the Bosch. ACD were twice the price as Bosch however. I also replaced the air filter and PCV valve. My next thing is the tranny filter and fuel filter.

But next time I may just as well let the dealer do the tune-up for $200 and spare the curse words for another task!

[hufhouse]

I just replaced the plugs on my Montana. I did this in conjunction with the dreaded lower intake manifold gasket replacement, so I had a lot of clearance to the rear plugs.

I don't know how anybody could ever do this job without having the engine torn down. I literally had to use a hammer with my ratchet to get all six plugs out. My little office boy arms just didn't have enough "torque" to loosen the rusted plugs. I don't have a large (1/2") ratchet set...only a 3/8". So, my ratchet isn't that long. However, I had to beat it with a hammer about three times to loosen each plug. There's no way I could have done that without having the engine torn apart.

Replacing the rear plugs...not a job for the faint of heart.

Rotating the engine forward a few inches is easy. I would say that you would almost have to remove the ignition coil to get to the back, though.

Good luck!