Rotating engine forward to get to the spark plugs

[N7OKN]

In order to rotate (tilt) the engine forward (to get to the back side
of the engine) in a 2001 Chevy Venture, the two "dog-bone" strut
mounts are removed (the ones that bolt to the front of the engine
compartment), but the bracket that the passenger side strut attaches
to, that is bolted to the engine must also be removed because it will
hit the radiator fan if not removed when the engine tilts. For a 1999
or earlier model, the bolts are clearly shown in the Haynes manual,
but not the 2001 model is different. What needs to be removed to get
this engine mount bracket off, and where are the bolts? I only see the
one on top, on the front. Any URL showing a picture would graetly
help, but detailed description would suffice.

Thank you in advance
John

[hufhouse]

John,

I just tilted the engine on my 2000 Montana and did not remove the bracket to which you are referring. The engine can only rotate about 5" or so for slightly better access. Unless yours is different, I don't think you'll need to remove that bracket.

[03CavyMan]

Maybe this will help, I couldn't find a very good picture, but I circled the bolts you have to remove in red. I believe the head of the bolts are 15mm and the nuts are 13mm. You can't see the one on the right very well thanks to that wiring harness that's in the way. but it looks the same as the left one. Anyways, remove those bolts and then you can pull the engine ahead to get at the rear plugs. They are still a major pain in the ass, but it's do-able.

A ratchet strap works real well for moving the engine ahead if you have access to one.

[cdru]

I've found that actually removing the dog bones completely, both bolts on each one, will allow you to squeeze a few more degrees of rotation out of the engine. Depending on what you are trying to get to, this may or may not be advantagous.

[Glen_T]

A few years back, I owned a 1990 Grand Prix. It, too, had an engine impossibly close to the firewall. Similar to my current Montana, you loosened one bolt of the dogbones and pulled the engine toward you to allow a large enough gap to change the rear plugs. The big difference is that the dogbones had a second hole in them that you slid the bolt into to keep the engine securely rotated forward. Really slick design, so of course GM stopped doing it!

I figure the lawyers got involved because some idiot rotated the engine this way, and then forgot to put it back the way it was originally, and someone either got hurt or sued GM for damage since the engine would be effectively loose in the engine compartment.

I haven't looked that closely, but the ones in my old Pontiac were cast - are the ones in our vans stamped steel? Any chance they have the extra hole?

Sometimes engineers have good ideas! (I'm biased since I am one...)

Glen

[jrdwyer]

I was able to change the rear spark plugs without rotating the engine. This is not easy to do, but it is possible using front wheel ramps and some ratchet extension and/or swivel type tools. The hardest part was removing the spark plug wires in a tightly confined area with little room for leverage. Doing it this way might not be possible if one has huge hands and forearms as the space available to work is very limited. 2001 Olds Silo.

[cdru]

Originally Posted by Glen_T

I haven't looked that closely, but the ones in my old Pontiac were cast - are the ones in our vans stamped steel? Any chance they have the extra hole?

I remember that feature on my dad's GP. The ones on the U-bodies are cast still, but there is no hole that you can use like on the GP. There is a engine hoist loop that can be used with a ratchet strap. I don't think the same type of setup as with the GP would work with our vans due to the amount you'd have to move it as well as clearance with a variety of different engine components.

[MIBPreacher]

Just today I finished what I have been putting off for about a year, changing the last 2 back plugs. Now let me tell you, this is a PITA, but I have done this both ways. Last year, I wanted to change my plugs and get some better mileage, the only problem was that with 135,000 miles, the rear plug boots had seized to the plugs. One of my friends is a certified GM mechanic and I asked him how would he go about changing the plugs, he told me about the two bolts, too loosen them and it will lower the engine. He told me to make sure I had a jack supporting the engine BEFORE I loosen them. I loosened the bolts like he told me to and he told me not to lower the engine lower then about 4 inches. He told me that If I went lower than that I can damage the CV shafts by pulling them out too far. After this I was able to get a little bit more clearance and I was able to pull one boot off, but broke the plug which freaked me out but was able to get the plug off anyways.

ABSOLUTELY MUST HAVE ITEMS TO TUNE UP A VENTURE.

1. Deluxe boot puller that look like long pliers dressed in rubber.
2. A new sparkplug socket. I was still using the old style with the rubber insert. The new ones are awesome and magnetic, no more leaving the socket behind.
3. Aftermarket ramps
4. Nice comfortable creeper for rolling around on the concrete.

When I first attempted this tuneup, I didnt have the parts 1 & 2 above, and it was a pain, its hard to see, you need a mirror to see the hole for the plug to go in,

Now today, I figured I am going to get this done and over with. Mind you I am 6'4" and about 275 pounds, I wasnt about to lower the cage again. I rolled under my van after putting it up on ramps and I could see the plugs easily. There is actually room for you hand to go up and reach the plugs and maneuver around some. The boots were still siezed! I used my boot pliers and that helped a little as I could feel it click some but I said screw it, I am prepared to replace the wires. I went topside dropped a wire down back, went down below and between me tugging on the wire itself and using the plug pliers to twist the boots every direction possible, I was able to pull each one off like that. I took my new magnetic socket and a 4" extension and was able to change the plugs with out lowering the engine at all! The back two plugs had deteriorated to a .080 gapping, which is way off. I said, you know, I better check the front ones, so I used my boot pliers and when I pulled the middle wire, the wire was actually seperated in the boot, only being held on by a thin piece of wire about the width of a human hair. After a year of use, the front 3 plugs had deteriorated to almost .070 gapping so i corrected them back to .060 I also want to mention that I used the boot grease that they sell at autozone to keep all my boots from seizing again, it was .99 cents. I think it will be worth it.

For my tune up, I used the bosch platinum sparkplugs, it had the acdelco originals in it : ) I also used the lifetime warranty 7mm Bosch wires from Autozone also. They were 29.99 plus tax.

Runs tremendously better now. waiting to see what improvement i will get.

You know what got the bug started, a check engine light according to autozone regarding the catalytic convertor, or the plugs. I think it was code somethingsomething240.

[JJ Newel]

Why do you have to place a jack under the engine do you have to do this?

[MIBPreacher]

Originally Posted by JJ Newel

Why do you have to place a jack under the engine do you have to do this?

The subframe is hinged at the rear and bolted up front with 2 large bolts. You use the jack to slowly lower the subframe so you dont screw up your van.

[DRW1000]

So back the "dog-bone" bolts. Someone said that they used a ratchet strap to move the engine forward.

When the bolts are removed does the engine fall back or sit where it was?. Does it take much force to rotate the engine? I was thinking of rotating it and tying it to something.

[MIBPreacher]

Originally Posted by DRW1000

So back the "dog-bone" bolts. Someone said that they used a ratchet strap to move the engine forward..

This is complete and utter B.S. I wouldnt do it, yes you can rotate the engine forward with a strap, all the while placing unneeded stress on the engine/tranny mounts. This is not needed when you loosen the two subframe mounts.

Originally Posted by DRW1000

When the bolts are removed does the engine fall back or sit where it was?.

When you loosen the bolts, and you do not have a jack underneath, you will drop the engine to the floor.

Originally Posted by DRW1000

Does it take much force to rotate the engine? I was thinking of rotating it and tying it to something.

If you are going to do something do it right, our vans are already predispositioned to fail on us, why add more to the stress?

[DRW1000]

Well MIBPreacher I read your earlier post and I am not sure of what two bolts your mechanic friend was talking about? The ones that apparently allowed you to drop the engine 4". Why would this be less stress on the engine/tranny mounts?

[MIBPreacher]

Put the van on some ramps. creep under your van and take a look at the sub frame assembly. Now close to the bumper if you follow along the subframe you will see two large holes if I remember correctly. Look inside these holes and you should see a really large bolt sitting inside it. If you loosen these two bolts (one on either side) and you have no jack to support it, you will drop the front half of the entire assembly and royally screw up your van costing hundreds if not in the small thousands of dollars in repair work needed. the cv shafts will be damaged as well as where they connect to the transaxle.

You asked "Why would this be less stress on the engine/tranny mounts?"

Think about this logically. if you exceed the approx 4", you damage the front engine mounts. The engine mounts have some give in them but the object is to not have to replace them.

The whole point of this thread is that some people are telling Venture owners yeah just drop those two bolts and you can easily get to those back spark plugs. When I had lowered my cage, it was becuase my alternator had went out and I needed to replace it. the extra inches I got helped out a lot for that task. It was a pain to try and get to the back spark plugs, I ended breaking one off before removing the rest of it. It is much easier to get the back plugs when you go from underneath. My friend, the one I mentioned, is a certified GM mechanic, not an apprentice no offence to the above poster. When my intake manifold went out under warranty, I had him do it at the chevy dealer he works at. He replaced alot of other internal engine parts that he also said are known to wear prematurely. I trust him and if he tells me I will damage the driveline if I lower it more than 4 inchs, I will believe him. To each his own. Just trying to help people not mess up their van.

[Glen_T]

Guys, not sure where you're getting your information, but the removal of the two front "dogbone" struts will not make the engine drop or put any added stress on anything. Those strut just limit the amount of rotation the engine can have, and resist the torque of the engine. So, yes, you have to have them to safely drive or even accelerate the engine, but per the 2003 shop manual, this is the preferred method to remove the rear spark plugs.

Remove the throttle body air duct, set the parking brake, shift the transaxle into neutral, and then remove the strut bolts and swing the struts out of the way. You can then just grab the engine and rotate it forward enough the get your hand back there. The manual has a special tool which is just an adjustable strap that prevents the engine from rotating back against the firewall so you don't pinch your arm.

Think about the force and torque balance...how could two horizontal struts prevent the engine from dropping to the floor. But removing the subframe bolts could make that happen....but the idea that dropping the subframe is somehow less stressful to the engine mounts and the whole system compared to rotating the engine in a direction it is meant to roate doesn't make sense to me....

Anyway, the factory manual recommends the engine rotation, I've done it plenty of times in the past, and it isn't a problem....good luck, Glen