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"95 DOHC Cutlass Convertible Spark plug replacement


Galaxie500XL

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What's the best method for getting to the back 3 plugs on a DOHC Cutlass? The fronts are easy, but an awful lot seems to be in the way of the back 3...

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It doesn't look like much fun...I assume that a ratcheting strap would be best to move the motor forward...thanks!

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How I did mine:

 

Remove weatherstripping along cowl. The Previous owner had already cut 3 slots into the cowl that allowed the extensions to to get down to the plugs with no issues. You can do this, or:

 

Parking brake on, trans in neutral, undo dogbone, wratchet strap forward, and go at it.

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I appreciate the good information...I'm not looking forward to it. I console myself by thinking "At least I'm not replacing the timing belt"...

 

 

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Well, looked under the hood, and ran across two problems...

 

The convertible has a strut tower brace running across the back, so pulling the hood seal won't really help much...

 

And, I think I found the issue with my plugs...two of the front three plug wires left the metal connector for the plugs behind...I'll need new wires.

 

As I don't have $175.00 to buy the AC/Delco plug wires, what works well with the DOHC?

 

I'm finding at the local stores Bosch, Autolite, Duralast (Autozone).....all for around $75.00. Are any of those good for the 3.4 DOHC?

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Honestly you can't beat the AC Delcos.

Someone else might have an opinion of the others but the only time I would stray from the AC Delcos is if I was upgrading to an 8mm wire (Magnacore, about $300 CDN a set)

 

Take the strut bar off? its 6 bolts...

 

I should get Matt to check out this thread... he has a good method of tilting the engine forward, I don't want to try to tell you what it is and get it wrong so I will let him know about this thread.

 

Jamie

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I was under the impression those six bolts comprised the upper stut bearing mount...didn't want to mess up the alignment of the front suspension.

 

I appreciate your help...I was surprised at your recommendation of the AC plug wires...but it does make sense. I've had bad experience with Auto Zone and Advance Auto Parts store brand wires..

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Like I mentioned, I have no experience with the other companies you mentioned. However I do know that for a lot of applications you can't beat OE

 

You won't mess up the alignment pulling the strut bar.

However I can't remember if the mounts will pop out if you take those plates off, so it wouldn't hurt to have a jack under the car, lol.

I have a coil over conversion on the front of mine and so when I take those plates off the mounts get pushed up and are a bitch to get back down, lol.

 

Maybe someone else can pipe up on that topic

 

Jamie

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Thanks a bunch for the help...I'll try to track down plug wires in the morning...maybe I'll find a good deal on them somewhere.

 

I'm not sure if the wires were already bad, or if I broke them pulling them out of the holes...ironic, I expected if I broke anything, it would be that crazy plastic probe, not the actual terminal end of the wire itself...

 

The funny part is, I stuck the plug wires back, and the car runs just fine...but there's no way I'll leave it like that.

 

Thanks again for the help, any other suggestions are greatly appreciated!

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i have extra strut tower plates laying around... If i am doing something that requires removal of the STB, I stick those on from a non-STB car. (just in case) should be easy to get from a nearby j/y.

 

If you have newer struts which have a good gas charge they can push the upper rubber mount up and out.

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Thanks to all for your suggestions...I found an independently run parts store here in town, found the genuine AC/Delco plug wires for $131.00, well below list price...the guy said he was glad to see them go, they've been on his shelf for 6 years.

 

If you hear an anguished scream later today, that will be me. :)

 

BTW, I assume the general advice to apply anti sieze compound to the plug threads, and dilectric compound to the boots applies?

 

Thanks again!

 

Daniel in Knoxville

 

 

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If you dont have access to a ratchet strap, back the car up onto ramps or on a hill, so that the nose of the car is facing downward. Put the car in park allowing weight of the car to rest on the park pin in the trans. Remove the weatherstripping behind the plenum on the firewall. Unbolt the dogbone. The weight of the car will roll the engine forward allowing you to slip an extension down between the plenum and the lip on the firewall.

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Thanks to everyone for their assistance and suggestions. It took some doing, but it's done, and it's made a huge difference in the way the car runs. I stuck with the stock AC plug, and the AC/Delco wires. I DID take the strut tower brace off the car, and the weatherstrip on the back of the hood. The previous owner had bent the lip of the firewall slightly to allow access. The absolute worst part was running the new plug wires on the firewall side...it's kinda hard to push a plug wire through a gap between the front engine plate and the cylinder head, but I found a way.

 

At least 4 of the 6 wires had problems. All 3 front wires had severe rubbing damage, because the previous installer had routed the wires in such a way that they rubbed stuff, two front wires had the spark plug terminal no longer crimped to the wire, and #5 on the back had a cut in the insulation about an inch long, and the outer insulator was separated (wrapped loosely) along a 3-inch length of the wire. I'm surprised the car ran as well as it did.

 

Hopefully, this will improve mileage, I've not seen over 20 MPG since we bought the car last month, and I ususally get slightly better than EPA rated mileage from my cars.

 

Thanks again, everyone...time now to collapse in a heap, and count my blessings that the job is done!

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$131.00 is pretty high for plug wires, but I've had very bad experiences with the Xact wire Advance Auto Parts sells. I put a set on two Buick Century's I had, and within 6 months, both were misfiring due to the heat between the engine and firewall.

 

It was worth the extra to not have to do the job again anytime soon.

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