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Hi,

So I am shopping around for a car and there is a 1999 Seville SLS that I am currently looking at. It currently has just fewer than 48k miles on it and is pretty clean inside and out. However there are a few issues that I have noticed and I wanted to get some advice on whether or not they are red flags and what else I should look at.

The car has a stuttering issue at idle, it feels like it will stall but it doesn’t. The person selling it has a friend with a tool to read the trouble codes and it comes up with information about cylinder 8 misfiring. He suggested that the plugs and or wires may need to be changed or at least clean the plugs. When driving it seems fine, it has no trouble getting up to speed.

The car was also low on coolant looking around the car and reservoir it looks like it might be leaking from the reservoir cap. When I looked into the coolant reservoir I noticed that it was green. My understanding is that GM cars use dexcool which should be orange. Is this a problem?

Any other advice you guys may have would be great. Any other problems I should be looking for on a Cadillac of this age?

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The plugs and wires should not need replaced at 48k. The plugs are platinum 100k plugs. The coolant level issue could be a headgasket problem or some kind of coolant leak and the cooland you are seeing around the reservoir could be what they have spilled when filling the reservoir.

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before refilling I noted the coolant around the cap and rim of the reservior. thats why I thought the cap might be leaking. I wouldn't think a head gasket would go out on an engine with so few miles. but defintaly going to look into it.

I'll get a chance later today to take a look at the plugs and see if anything is amiss.

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Be VERY careful!!!!!!!!!!!

Get the coolant checked for combustion by products BEFORE buying this car. The 93 through 99 can have head gasket problems if the coolant is not maintained properly, so you MUST eliminate that possibliity BEFORE buying it. DO NOT BUY IT, WITHOUT DOING SO, I don't like what you are telling us

One of the symptoms of a bad head gasket is a misfire.

Drive the car hard, at highway speed and up hills to test the head gasket, and smell the coolant tank to see if it smells of exhaust fumes

The green coolant should not have been used. But it is important to know that from this point on, the coolant change interval is now 2 years and 24,000 miles and NOT 5 years and 100,000 miles even if you used Dexcool as the cooling system is now plated with the green's silicates. Someone used improper maintenance procedures on this car by using the green, you will find a lable under the hood and it states in the owners manual that Dexcool is the proper coolant

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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While 48K is awfully early for a HG problem, '99's are the worst year for them.

Agreed, BUT

if the coolant has not been changed, mileage does not matter

I have seen too many odometers turned back, my neighbor does it regularly

I would look it over carefully, not to sound negative, but with the miss and coolant loss, age, etc, I would want to confirm all is well

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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You have two red flags here. I would run away from it.

....The car was also low on coolant looking around the car and reservoir it looks like it might be leaking from the reservoir cap.

Low on coolant and maybe spillage at the pressure cap?? Insist the seller install a new OEM pressure cap and observe the results.

....When I looked into the coolant reservoir I noticed that it was green. My understanding is that GM cars use dexcool which should be orange. Is this a problem?

It certainly is for me. The cooling system has not been serviced with the proper coolant. And I would want to know why that is. You can bet your barn that a Cadillac dealer service department did not put green ethylene glycol in that cooling system.

Forget the mileage and forget the cosmetics; concentrate on the cooling system issues.

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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Well I hope it is a nice barn because my Cadillac dealer only puts in green unless you request Dex Cool at a service. They have been doing it for years. I recall that when I purchased my 99 Eldo new they even suggested changing it out with 4 miles on the vehicle. FYI, in 99 there was a manufacturing problem with the NS and a bulliten for dealers to pull out a head bolt and measure the hole depth to avoid early bolt failure. I believe holes were drilled too deep allowing coolant to enter from the base of the hole. Most dealers failed to do the complex check but claimed the service was done to get paid. I would not run away from a 48K car but I would definately agree that the warning signs are there and should be evaluated by a competent NS mechanic. Not just any mechanic will do as diagnosis can be a bit tricky in the early stages of a gasket blowing. The Sevilles effected by this bulliten are as follows and may be worth checking out.

1999 Cadillac Seville built in Hamtramck plant between vin # XU938976 to XU940640 GOOD LUCK

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Well I hope it is a nice barn because my Cadillac dealer only puts in green unless you request Dex Cool at a service. They have been doing it for years. I recall that when I purchased my 99 Eldo new they even suggested changing it out with 4 miles on the vehicle. FYI, in 99 there was a manufacturing problem with the NS and a bulliten for dealers to pull out a head bolt and measure the hole depth to avoid early bolt failure. I believe holes were drilled too deep allowing coolant to enter from the base of the hole. Most dealers failed to do the complex check but claimed the service was done to get paid. I would not run away from a 48K car but I would definately agree that the warning signs are there and should be evaluated by a competent NS mechanic. Not just any mechanic will do as diagnosis can be a bit tricky in the early stages of a gasket blowing. The Sevilles effected by this bulliten are as follows and may be worth checking out.

1999 Cadillac Seville built in Hamtramck plant between vin # XU938976 to XU940640 GOOD LUCK

This is old news, we have a thread on the issue, no big deal, the problem is covered indefinately if your car has a VIN number in this range.

As far as a GM dealer dumping the long-life Dexcool and refilling with the 2 year/24,000 miles green coolant on new cars, that green coolant then introduces silicates into the cooling system and GREEN is than needed from that point on. There is a sticker under the hood that states that Dexcool is required. So the next owner uses Dexcool not realizing that green was used and thinking he has long-life in waits 4 years to change his coolant instead of changing it in 2 years as now required because green was used. The decision by that dealer to me borders on total incompetence, and they should be reported to GM for improper maintenance and procedures.

Please supply the dealer name so that I can report them to GM, for improper maintenance and procedures. Send it to me by PM, if you are uncomfortable with posting it publically.

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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Maybe the dealer IS using non silicated long life coolant. Some of those have a green color, though admittedly probably a different shade of green, the the average guy may just see "green".

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Probablty not old news to a new member who has no Caddy experience such as JR29. I guess I'll leave further responses to those that know it all!!

Listen every time you come here you have an attitude,

YOU started with the BARN comment

Please stay out if you can't post without having an attitude or an axe to grind

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 only replied as I did due to you arrogant reply to what I thought may be important information to someone asking such a question as JR29 did. Do you think that your reply of “This is old news, we have a thread on the issue, no big deal” shows respect for others input? Many of us have not lived on this board for years thus knowing all the old news as you do. I thought JimD’s barn comment was funny and thought it may be important to realize that not all dealers go by the book and I have personal experience that shows it. JimD, my apologies if you took offense!! Sorry to disrupt your “world” BodybyFisher.

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Well we have some history as you know and its not good, you like to be arrogant yourself

You made a statement regarding DEXCOOL that was disturbing, that started my so called arrogance. Your statement that it is a nice barn, followed by what I consider improper service procedures DID NOT come out as funny in response to JimD's so called 'funny' statement.

Again, provide your dealers name and location so that I can report them for improper procedures, what they are doing is dead wrong no ifs ands or buts.

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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