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RED HOT spark plug wires

Started by Cape Cod Fleetwood, March 16, 2018, 04:52:23 PM

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Cape Cod Fleetwood

Hey folks,
had to dump the water out of the car and refill with 50/50 Prestone, another storm coming this time with hideously cold temps.
I let the car run until the heat was blasting inside, nice!
But the car felt/sounded rough, I just changed plugs and wires.
The spark plug wires on the drivers side, from the firewall forward 3 plugs, were RED HOT at the plug
compared to all the others.
What up?
As always, so grateful for the information.

\m/
Laurie!
There are 2 kinds of cars in the world, Cadillac and everything else....

The Present -1970 Fleetwood Brougham

The Past -
1996 Deville Concours
1987 Sedan De Ville "Commonwealth Edition"
1981 Coupe De Ville (8-6-4)
1976 Sedan De Ville
1975 Sedan De Ville

The Daily Driver and work slave -
2008 GMC Acadia SLT *options/all

Mike Josephic CLC #3877

I can't think of any electrical reason that would effect
only 3 plugs. I think it's the way the wires are routed. 
On top of the engine, there should be several "wire looms".
These are plastic holders that keep the wires properly
spaced and away from the engine hot spots.

They may be missing on your car -- they usually are plastic
and fall apart on cars of this age.  Those 3 plug wires may be
too close to the manifold on that side.

Here is an example of what they look like:
https://www.oreillyauto.com/detail/mr--gasket-4367/performance-16477/engine-16841/ignition-16593/spark-plug-wire---looms---separators-17886/mr-gasket-8mm-spark-plug-wire-holder/3677/4513984

Mike
1955 Cadillac Eldorado
1973 Cadillac Eldorado
1995 Cadillac Seville
2004 Escalade
1997 GMC Suburban 4X4, 454 engine, 3/4 ton
custom built by Santa Fe in Evansville, IN
2011 Buick Lucerne CX
-------------------------------------
CLCMRC Museum Benefactor #38
Past: VP International Affiliates, Museum Board Director, President / Director Pittsburgh Region

Bobby B

Quote from: Cape Cod Fleetwood on March 16, 2018, 04:52:23 PM
I just changed plugs....

Maybe you answered your own question...
                                       Bobby
1947 Cadillac Series 62 Convertible Coupe
1968 Mustang Convertible
1973 Mustang Convertible
1969 Jaguar E-Type Roadster
1971 Datsun 240Z
1979 H-D FLH

Cape Cod Fleetwood

Quote from: Bobby B on March 16, 2018, 09:48:20 PM
Maybe you answered your own question...
                                       Bobby

Please continue....
\m/
Laurie?
There are 2 kinds of cars in the world, Cadillac and everything else....

The Present -1970 Fleetwood Brougham

The Past -
1996 Deville Concours
1987 Sedan De Ville "Commonwealth Edition"
1981 Coupe De Ville (8-6-4)
1976 Sedan De Ville
1975 Sedan De Ville

The Daily Driver and work slave -
2008 GMC Acadia SLT *options/all

Cape Cod Fleetwood

Quote from: Mike Josephic  CLC #3877 on March 16, 2018, 08:10:01 PM
I can't think of any electrical reason that would effect
only 3 plugs. I think it's the way the wires are routed. 
On top of the engine, there should be several "wire looms".
These are plastic holders that keep the wires properly
spaced and away from the engine hot spots.

They may be missing on your car -- they usually are plastic
and fall apart on cars of this age.  Those 3 plug wires may be
too close to the manifold on that side.

Here is an example of what they look like:
https://www.oreillyauto.com/detail/mr--gasket-4367/performance-16477/engine-16841/ignition-16593/spark-plug-wire---looms---separators-17886/mr-gasket-8mm-spark-plug-wire-holder/3677/4513984

Mike

Hi Mike,
there is no support on the starboard valve cover like there is on the port side to support one of these separators. Also the wires are so long on the starboard side, they're not even close to the engine.
?

\m/
Laurie
There are 2 kinds of cars in the world, Cadillac and everything else....

The Present -1970 Fleetwood Brougham

The Past -
1996 Deville Concours
1987 Sedan De Ville "Commonwealth Edition"
1981 Coupe De Ville (8-6-4)
1976 Sedan De Ville
1975 Sedan De Ville

The Daily Driver and work slave -
2008 GMC Acadia SLT *options/all

Mike Josephic CLC #3877

Hmmmm.....

Are the wires too long on the starboard side?  If there are
no supports (wire loom) to hold them in place then they are
going to fall onto the engine sooner than later.  The looms also
prevent cross contact between the wires, that become an issue
as they age (tiny cracks in the cover).

Two thoughts:

Did you get the "correct" wire set for your car -- or a generic
set "one size fits all".  These wire loom supports are rather
flimsy pieces of metal, they can and do break off. Any evidence
of that?

I'm running out of ideas here -- long distance diagnosis is
not easy.  I don't see how just changing the plugs (which I'm
sure you know how to do) could be the issue here.

Mike
1955 Cadillac Eldorado
1973 Cadillac Eldorado
1995 Cadillac Seville
2004 Escalade
1997 GMC Suburban 4X4, 454 engine, 3/4 ton
custom built by Santa Fe in Evansville, IN
2011 Buick Lucerne CX
-------------------------------------
CLCMRC Museum Benefactor #38
Past: VP International Affiliates, Museum Board Director, President / Director Pittsburgh Region

wrench

First off, let me say I have not experienced this specifically.

My thoughts would be to check that the 3 plugs in question are tight, leaking compression could add heat to those areas.

Make sure the wires are on tight on those 3 plugs...

Another thought would be maybe a leaking exhaust manifold itself or a leak at the exhaust outlet connection to the exhaust pipe on that side.

I would then take an infrared thermometer (better yet I think infrared imagers are getting cheaper) and quantify the temperature difference.

It could be also some large air bubble at that part of the head or block left over from the coolant changeout that is causing a temp split.

I have not been following your resto that closely to understand whether or why water as coolant was necessary for winter storage, this could result in a cracked water jacket somewhere in that area ...

Just brain storming...
1951 Series 62 Sedan
1969 Eldorado
1970 Eldorado (Triple Black w/power roof)
1958 Apache 3/4 ton 4x4
2005 F250
2014 FLHP
2014 SRX

Glen

   I can not see this being an electrical issue.  The on-off cycle of the spark plug would not cause that kind of heat.  It has to be something to do with exhaust leaks.   

I second the thermal camera, I have a Flir TG130 I picked up for $200.  Much better than the infrared thermometer that only reads out a temperature.
Glen Houlton CLC #727 
CLCMRC benefactor #104

DeVille68

Is the heat range of the spark plugs correct? Some brands rate high to low with a number from low to high and others are vise versa. Easy to buy the wrong heat range.
However, I would still think that it is unlike to have red hot plugs just because the heat range is wrong?! :o
1968 Cadillac DeVille Convertible (silver pine green)

Jeff Rosansky CLC #28373

#9
 Good morning.
May I suggest you rotate the plugs and see if the problem follows the plug or stays at the cylinder. I just put a set in the 55 and had 3 of the 8 brand new out of the box plugs  fail an ohm meter test. If no luck there then do the same with the wires.... even if they are too short it won't matter for testing purposes. Or you can just replace them temporarily with ones from your old set.
Also, when you pull the plugs, check to be sure the washers/gaskets come off as well. Check to be sure there aren't old gaskets/washers left over from a previous change. They sometimes glue themselves to the head over time.
Jeff
Jeff Rosansky
CLC #28373
1970 Coupe DeVille (Big Red)
1955 Series 62 (Baby Blue)
Dad's new 1979 Coupe DeVille

Bobby B

#10
Quote from: Glen on March 17, 2018, 02:26:53 AM
   The on-off cycle of the spark plug would not cause that kind of heat.
Glen,
  Sorry to tell you that you're dead wrong. A bad spark plug, or the incorrect heat range can cause plugs to run hot and heat up the jacket ends.There is a reason why a plug heat is designated for a specific stock engine from the factory. Years of research went into that. Adjacent cylinder plugs/area might also be affected. Lean burn, hot spots, incorrect timing, etc. will also cause the manifold to be extra hot and also heat up the plug wires. Funny how it only started happening after she changed the plugs /wires? I think an exhaust leak would be more obvious visually around the area or sonically, unless that was never checked. Some cars were only meant to run on certain plug/wire combinations. Some newer cars will ONLY run properly with stock components. Ask me how I know....A resistance check on every wire and plug would be my first line of attack if an exhaust leak was not evident.
                                                                                                                                                                             Bobby
Quote from: Jeff Rose                                         CLC #28373 on March 17, 2018, 08:55:17 AM
I just put a set in the 55 and had 3 of the 8 brand new out of the box plugs failed an ohm meter test.
Jeff

Thank You. Been there, done that.... ;)

Quote from: DeVille68 on March 17, 2018, 07:27:32 AM
Is the heat range of the spark plugs correct? Some brands rate high to low with a number from low to high and others are vise versa. Easy to buy the wrong heat range.

Thank You. Been there, done that.... ;)
1947 Cadillac Series 62 Convertible Coupe
1968 Mustang Convertible
1973 Mustang Convertible
1969 Jaguar E-Type Roadster
1971 Datsun 240Z
1979 H-D FLH

cadillacmike68

Hi (I've been sick but I can still type (badly)).

What plugs did you use? The correct ACDELCO ones are R45XLS
What wires? The best wires for these cars is ACDELCO 508D

Do NOT put platinum plugs in these cars. I learned that the hard way.
Regards,
"Cadillac" Mike

Cape Cod Fleetwood

Quote from: wrench on March 17, 2018, 12:37:32 AM
Make sure the wires are on tight on those 3 plugs...

We have a winner...
Sorry guys, but you're dealing with a chick here who hasn't been under the hood of a car like this since she was a teenager. That's my story and I'm sticking to it.

<sigh> The 3 wires weren't on tight. And I found another one not on snugly, the one on the pax side at
the firewall, I just can't get it on tight.

The wires are AC Delco 508D, plugs are R45XLS, sourced from Summit Racing.

I owe the forum a round, I'm ready to pay up. Sorry.

\m/
Laurie  ::)
There are 2 kinds of cars in the world, Cadillac and everything else....

The Present -1970 Fleetwood Brougham

The Past -
1996 Deville Concours
1987 Sedan De Ville "Commonwealth Edition"
1981 Coupe De Ville (8-6-4)
1976 Sedan De Ville
1975 Sedan De Ville

The Daily Driver and work slave -
2008 GMC Acadia SLT *options/all

Mike Josephic CLC #3877

Hey Laurie -- don't feel too bad -- at least you found the cause.
I think that's great!

You're not the first person that has seen this problem!

Mike
1955 Cadillac Eldorado
1973 Cadillac Eldorado
1995 Cadillac Seville
2004 Escalade
1997 GMC Suburban 4X4, 454 engine, 3/4 ton
custom built by Santa Fe in Evansville, IN
2011 Buick Lucerne CX
-------------------------------------
CLCMRC Museum Benefactor #38
Past: VP International Affiliates, Museum Board Director, President / Director Pittsburgh Region

Bobby B

Quote from: cadillacmike68 on March 18, 2018, 01:02:19 AM
I prefer the acronym FUBAR, which I'm sure you know what it stands for.
FFubar is more like it...... :o
                            Bobby
1947 Cadillac Series 62 Convertible Coupe
1968 Mustang Convertible
1973 Mustang Convertible
1969 Jaguar E-Type Roadster
1971 Datsun 240Z
1979 H-D FLH

Bobby B

Quote from: Cape Cod Fleetwood on March 17, 2018, 11:40:31 PM
I just can't get it on tight.

Did you coat the insides of the boots with some Di-Electric Grease?
                                                                                  Bobby
1947 Cadillac Series 62 Convertible Coupe
1968 Mustang Convertible
1973 Mustang Convertible
1969 Jaguar E-Type Roadster
1971 Datsun 240Z
1979 H-D FLH

cadillacmike68

New 508D sets have some of the dielectric grease inside the boots.
Regards,
"Cadillac" Mike

Cape Cod Fleetwood

Quote from: Bobby B on March 18, 2018, 01:22:32 AM
Did you coat the insides of the boots with some Di-Electric Grease?
                                                                                  Bobby

No I didn't Bobby.... would that make this problem go away?
And you want me to take off the 7 I have on tight? <sigh>
\m/
Laurie?
There are 2 kinds of cars in the world, Cadillac and everything else....

The Present -1970 Fleetwood Brougham

The Past -
1996 Deville Concours
1987 Sedan De Ville "Commonwealth Edition"
1981 Coupe De Ville (8-6-4)
1976 Sedan De Ville
1975 Sedan De Ville

The Daily Driver and work slave -
2008 GMC Acadia SLT *options/all

Cape Cod Fleetwood

Quote from: cadillacmike68 on March 18, 2018, 01:26:15 AM
New 508D sets have some of the dielectric grease inside the boots.

They do?
Mine didn't...
Is there a preferred vendor for dielectric grease for this application?
I have some in my tool box but I use it for home electrical when I see a lot of oxidation on switch/outlet
contacts near the shore. Same stuff?
\m/
Laurie?
There are 2 kinds of cars in the world, Cadillac and everything else....

The Present -1970 Fleetwood Brougham

The Past -
1996 Deville Concours
1987 Sedan De Ville "Commonwealth Edition"
1981 Coupe De Ville (8-6-4)
1976 Sedan De Ville
1975 Sedan De Ville

The Daily Driver and work slave -
2008 GMC Acadia SLT *options/all

cadillacmike68

My post got bypassed. The new 508D set that I got for my 1968 has the dielectric grease inside the boots, so yours should have had some also. Not a lot is needed and unless you stuck a pen or small screwdriver in the boot you would not have noticed it.

I'm checking out for tonight  I'm coughing more than breathing.

Yes your stuff is the same.

Regards,
"Cadillac" Mike