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Cracked Intake Manifold


Tommy_P

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First, I would like to say I am a new member and I am very impressed with this forum. I am currently a member of the Shelby forums and look forward to the same wonderful interaction here. With that being said, I'll get to my question. I am the original owner of a '98 etc, 87,000 easy miles. I've always taken great care of my vehicles but I'm wondering if I'm being taken to the cleaners by the repair shop. My "Service Engine Soon" light came on so I took it to the shop. The codes, 3 of them (I'll get you specific numbers), came up as 2 lean fuel codes and 1 misfire code. They told me they ran a smoke test and determined that the intake manifold was cracked. They also said 2 plugs were fouled and possibly the wires. Both the plugs and wires are original so I can see that, but the intake I'm wondering about. They said it is a plastic piece and that is what cracked. Has anyone heard of this? This shop has done a lot of work for me so I have no reason to believe they are dishonest. Thanks again and great forum guys.

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a tech should be able to point out where the manifold is damaged. or at least explain that the symptoms appear to show an intake leak. is it the manifold since they do warp but rarely crack or is it the intake gasket? i cracked my manifold by over tightening the bolts but it was on an end bolt that cracked and i found out the fracture was in a double wall area and really not leaking. it just looked bad.

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a tech should be able to point out where the manifold is damaged. or at least explain that the symptoms appear to show an intake leak. is it the manifold since they do warp but rarely crack or is it the intake gasket? i cracked my manifold by over tightening the bolts but it was on an end bolt that cracked and i found out the fracture was in a double wall area and really not leaking. it just looked bad.

The tech told me that they ran a smoke test and saw where the crack was. I'm still not sure if the actual manifold is cracked or just the gasket and they are adding in the extras. I told him to save the part so I can see it. Is there anything else I should ask for?

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We don't hear of a lot of cracked intakes if any, they even have a port that blows out in case of a backfire. Don't devalue the intake by calling it plastic. Plastic sounds CHEAP. The intake manifold is Nylon 66 thermoplastic, which helps cool intake air by conducting less heat from the engine.

KOPA NYLON-66 is a thermoplastic resin with excellent mechanical, thermal and electrical properties. It finds wide application in the production of automotive, electrical and industrial parts and components.

PROCESSING GUIDE

DATA SHEET

High tensile strength

Outstanding self-lubrication and abrasion resistance

Excellent chemical resistance

High temperature range

We have not had a lot of cracked intakes, but if they found a crack and they are honest, good for them. Where did they find a replacement?

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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We don't hear of a lot of cracked intakes if any, they even have a port that blows out in case of a backfire. Don't devalue the intake by calling it plastic. Plastic sounds CHEAP. The intake manifold is Nylon 66 thermoplastic, which helps cool intake air by conducting less heat from the engine.

KOPA NYLON-66 is a thermoplastic resin with excellent mechanical, thermal and electrical properties. It finds wide application in the production of automotive, electrical and industrial parts and components.

PROCESSING GUIDE

DATA SHEET

High tensile strength

Outstanding self-lubrication and abrasion resistance

Excellent chemical resistance

High temperature range

We have not had a lot of cracked intakes, but if they found a crack and they are honest, good for them. Where did they find a replacement?

I kind of knew it was not "plastic" but that is the term the tech used when he described it to me. I just want to make sure he is honest but he said the only place that you can order a intake manifold for that old of a car is the dealer. I'm going to stop by there on my way home and have another discussion with them. Any helpful hints???

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Well a new intake is going to be VERY expensive, I would try scrap yards first, keep in mind that this is a 98, to spend $1000 for an intake is too much.

Id want to see the crack, make sure they use new intake seals. They will find a gunk in the intake its not a problem and very normal, pay no attention to it

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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We don't hear of a lot of cracked intakes if any, they even have a port that blows out in case of a backfire. Don't devalue the intake by calling it plastic. Plastic sounds CHEAP. The intake manifold is Nylon 66 thermoplastic, which helps cool intake air by conducting less heat from the engine.

KOPA NYLON-66 is a thermoplastic resin with excellent mechanical, thermal and electrical properties. It finds wide application in the production of automotive, electrical and industrial parts and components.

PROCESSING GUIDE

DATA SHEET

High tensile strength

Outstanding self-lubrication and abrasion resistance

Excellent chemical resistance

High temperature range

We have not had a lot of cracked intakes, but if they found a crack and they are honest, good for them. Where did they find a replacement?

Another item that was made from "Nylon 66" was a Remington .22 caliber rifle that was named (drum roll please) the "Nylon 66".

They were produced from around 1958/59 to 1989/90. They are reported to be very reliable. Of course the barrel is steel. But the receiver's guide rails that the bolt slides on is Nylon. Some of these guns are reported to never have been cleaned and they still operate reliably forty to fifty years later.

Remington did meet a lot of initial resistance from the gun community who resisted buying a "plastic" gun. I will admit to being one of those skeptics. However, if I was in need of a "survival" gun that had to work, no matter what, I would not hesitate to pick a Remington Nylon 66.

So, Nylon 66 is a TOUGH, LONG LASTING material that doesn't need to be associated with the general meaning of the term "plastic"!

Britt

Britt
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We don't hear of a lot of cracked intakes if any, they even have a port that blows out in case of a backfire. Don't devalue the intake by calling it plastic. Plastic sounds CHEAP. The intake manifold is Nylon 66 thermoplastic, which helps cool intake air by conducting less heat from the engine.

KOPA NYLON-66 is a thermoplastic resin with excellent mechanical, thermal and electrical properties. It finds wide application in the production of automotive, electrical and industrial parts and components.

PROCESSING GUIDE

DATA SHEET

High tensile strength

Outstanding self-lubrication and abrasion resistance

Excellent chemical resistance

High temperature range

We have not had a lot of cracked intakes, but if they found a crack and they are honest, good for them. Where did they find a replacement?

Another item that was made from "Nylon 66" was a Remington .22 caliber rifle that was named (drum roll please) the "Nylon 66".

They were produced from around 1958/59 to 1989/90. They are reported to be very reliable. Of course the barrel is steel. But the receiver's guide rails that the bolt slides on is Nylon. Some of these guns are reported to never have been cleaned and they still operate reliably forty to fifty years later.

Remington did meet a lot of initial resistance from the gun community who resisted buying a "plastic" gun. I will admit to being one of those skeptics. However, if I was in need of a "survival" gun that had to work, no matter what, I would not hesitate to pick a Remington Nylon 66.

So, Nylon 66 is a TOUGH, LONG LASTING material that doesn't need to be associated with the general meaning of the term "plastic"!

Britt

Good information. Should I find the tech is not being truthful, I may acquant him with first hand knowledge of that info :blink:

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i was told it is not uncommon to see warped intake manifolds which can cause leaks. i found a good supply of intakes for my 96 at the boneyard. i cannot say if the 98+ is the same. its a common replace item on buick V6 motors. seems the lower intake is separate from the upper and the fall apart. that is a pricey fix also. even more so when you dump a lot of coolant into the oil and take out the motor but the caddy intake is dry. ask you mechanic to consider a used intake. much less money.

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i was told it is not uncommon to see warped intake manifolds which can cause leaks. i found a good supply of intakes for my 96 at the boneyard. i cannot say if the 98+ is the same. its a common replace item on buick V6 motors. seems the lower intake is separate from the upper and the fall apart. that is a pricey fix also. even more so when you dump a lot of coolant into the oil and take out the motor but the caddy intake is dry. ask you mechanic to consider a used intake. much less money.

The Buick V6 intakes are totally different than the Northstar. The Northstar does not have the upper and lower halves or EGR passages in the intake as the Buick V6.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Ok, here's the story. I called the service tech and told him I would be down to see the "smoke" test and confirm the crack before authorizing any repairs. He was very gracious and said he would have the machine hooked up awaiting my arrival. Once I got there, he and another tech turned the maching on and wouldn't you know....the smoke started seeping out of the intake, not the gasket as I was suspecting. There was a hairline crack which was the culprit. So I authorized the repairs, thanked them for their efforts to give me piece of mind, and shook their hands. On to the next crisis. :fighting0025:

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Ok, here's the story. I called the service tech and told him I would be down to see the "smoke" test and confirm the crack before authorizing any repairs. He was very gracious and said he would have the machine hooked up awaiting my arrival. Once I got there, he and another tech turned the maching on and wouldn't you know....the smoke started seeping out of the intake, not the gasket as I was suspecting. There was a hairline crack which was the culprit. So I authorized the repairs, thanked them for their efforts to give me piece of mind, and shook their hands. On to the next crisis. :fighting0025:

Where are they getting it?

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I am not sure where they ordered it from, I'm going to assume a dealer but I may be wrong. The cost of the part was $593.53 and labor was $237.00. I'm sure the part was at least double their cost. Is there a place you would recommend for parts? I need to find a cruise control and the control piece for the temp on the steering wheel (I'm not sure if that can be replaced).

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i replaced my intake so i know what is involved. moving injectors, making sure the intake gasket is installed right. changing out the throttle body and hooking up all the vacuum lines. its straightforward but time consuming. i hope the car runs like normal now. what part of the cruise system is wrong? who diagnosed it for you?

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I am not sure where they ordered it from, I'm going to assume a dealer but I may be wrong. The cost of the part was $593.53 and labor was $237.00. I'm sure the part was at least double their cost. Is there a place you would recommend for parts? I need to find a cruise control and the control piece for the temp on the steering wheel (I'm not sure if that can be replaced).

Try www.rockauto.com and www.gmotors.com

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I am not sure where they ordered it from, I'm going to assume a dealer but I may be wrong. The cost of the part was $593.53 and labor was $237.00. I'm sure the part was at least double their cost. Is there a place you would recommend for parts? I need to find a cruise control and the control piece for the temp on the steering wheel (I'm not sure if that can be replaced).

Try www.rockauto.com and www.gmotors.com

Thanks, I'll look at them.

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i replaced my intake so i know what is involved. moving injectors, making sure the intake gasket is installed right. changing out the throttle body and hooking up all the vacuum lines. its straightforward but time consuming. i hope the car runs like normal now. what part of the cruise system is wrong? who diagnosed it for you?

The car runs great now, very quiet and smooth as the day I drove it off the lot. Actually, when I picked the car up from the shop and drove it on the hwy the cruise did not work. It says on the display "cruise engaged" but it is not. I tried several times to activate it but it would not. I pretty much just thought the mudule went out in it. I guess maybe it could be a fuse?

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I would check the linkage from the cruise control vacuum servo to the throttle cable hookup on the throttle body.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Yeah, it can't work unless it's all hooked up, and it's a big job to find and hook up everything when you pull down a modern high-end engine intake and fuel injection. Let us know if you have trouble finding it. I would have to look, but I believe that my cruise control mechanism is between the throttle body and the firewall.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Yeah, it can't work unless it's all hooked up, and it's a big job to find and hook up everything when you pull down a modern high-end engine intake and fuel injection. Let us know if you have trouble finding it. I would have to look, but I believe that my cruise control mechanism is between the throttle body and the firewall.

Thanks Jim, I'll try to locate it and see if that is the problem.

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