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97 Seville SLS Northstar- smoking


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I have a 97 Cadillac Seville SLS with the NorthStar engine in it. When we bought it it was overheating bad, We gave it a flush cause the ones that had it before use ran pure water in it for about a year. Then we put the correct radiator cap on it along with the correct thermostat along with the dex cool antifreeze. That pretty much stopped the overheating.... then we started smelling fuel and the FPR was messed up so bad it was sending fuel into the vacuum line that connects to the top of it. So we got another FPR and a new vacuum line. Now it only runs hot on a steep grade we are having white smoke come out of the tailpipes that smells like fuel. When you take the radiator cap off you also smell fuel and the antifreeze leaks down but there is no leaks appearing under the vehicle. Can someone please help I love my Cadi but if it keeps on I am going to have to trade it for something else. <_<

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If the exhaust is 'blowing' white smoke and smells sweet (antifreeze burning) it may be a headgasket. Some of the Northstars have also been reputed to have loosening intake manifold bolts that could be allowing some coolant to be burned. These, just a couple of miscellaneous ramblings, but also have been seen in an around the Cadillac forums. Perhaps someone else (with more knowledge of the N*) will chime in soon and corroborate or dispel my eval; good luck.

Chuck

'19 CT6, '04 Bravada........but still lusting for that '69 Z-28

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I appreciate your response thi just really really has me so confused. Cause I was aways taught that blue tint smoke was fuel white smoke was water... well this is white but smells like fuel but et antifreeze is going somewheres. but again thank you I may check the intake bolts to be on the safe side.

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I would go to autozone or similar and use their loan a tool program to get a block test kit and test for combustion by products in the radiator. If it fails that test you can be sure you have a head gasket problem. Do not put in new coolant prior to testing, as you can get a false result. White smoke would likely be water, but if it smells like fuel you may have two problems at once. Coolant test first.

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barczy01 since I can't figure out how to add pictures on here... we gave $450 for this Cadi the only damage done to it is the passenger side headlight lens cover is busted but the light still works. we have most of the over heating fixed I just can't understand why it is showing white smoke and it not be water but smells like it is burning rich. when my Father always taught me blue smoke was fuel white smoke was water black smoke was oil. so this really really has me confused. I believe it is worth fixing if I could figure out how to add some pictures I think you would too.

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Get a Bi products test done asap. Before you waste any time and money on anything else.

these cars use a dry intake so there should be no coolant loss or contamination from the intake.

What you describe sounds like breached headgasket. Just from my experience,

Get that test done asap, that should answer your questions

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th_102_2804_zpsca346b8f.jpg

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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It is a kit that tests for presence of exhaust gases in the cooling system. To do it you must not top off the coolant before the test.

The part shown in my picture gets filled to the line with the blue solution, then vacuum is pulled through the top and pulls the gases into the unit. Fluid stays blue is good. Likely means no gases present.

yellow is bad, Means gases are present

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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Btw, if you or your husband are handy, the kit can be rented for free at many big box auto stores like autozone. You just have to purchase the fluid. Make sure the fluid is fresh as it has a very short shelf life, and when it is old, the reaults get unreliable.

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ok don't know if this make any sense or not but we did that test on it and it showed that #2 & #7 were bad. Well a fried of mine told me to check the intake bolts that they do come lose from time to time so
I did and ran the test again and guess what all were blue. So yip yi horray.:)

I also checked the plugs and some of them weren't firing so we are going to replace the plugs in it and see how it does.

I really do appreciate everyone's inputs they really did help. If we are still having problems with it trust me I will let you guys know.

Thank you

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what test did you do on the cylinders?

I am kind of confused by the last reply to be honest.

The intake is a dry intake so it should not have anything to do with coolant.

The Bi products test is done at the surge tank and nowhere else.

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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jnstreen....I suspect you are getting help from someone that probably knows about cars in general, but these are a different animal. I would highly recommend trying what info you get here to the T, and not mixing, or letting someone lead you down a different path. I truly hope your car is fixed, but it doesn't add up. It sounds like someone did a compression test maybe? If you were having weak compression those bolts wont make a difference. They also wont keep water out, like rockfangd says, there is no water/coolant there!

In any case good luck, these are awesome cars.

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they call it a block test here. but you only you the surge tank. but after you do the original test it tell you how to break it down to pin point which cycliner it is bad on. it has you to remove one plug wire at a time and repeat the test on all 8 cylinders. at first the #2 and #7 cylinder show bad and someone told me to check the intake bolts that sometimes they may come lose and they were. so I tightened them down and doubled check the #2 and #7 and they remaned blue. Does that help rockfangd? I have noticed around the water pump some white color on some of the other objects around it so I plan on changing the water pump hopefully this next week.

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they call it a block test here. but you only you the surge tank. but after you do the original test it tell you how to break it down to pin point which cycliner it is bad on. it has you to remove one plug wire at a time and repeat the test on all 8 cylinders. at first the #2 and #7 cylinder show bad and someone told me to check the intake bolts that sometimes they may come lose and they were. so I tightened them down and doubled check the #2 and #7 and they remaned blue. Does that help rockfangd? I have noticed around the water pump some white color on some of the other objects around it so I plan on changing the water pump hopefully this next week.

Now i have more questions.

Youtube the dye test for the radiator/surge tank like rockfangd mentioned.

If you can just let us know if someone took off your radiator cap, put a rubber and plastic test kit on it, filled the clear plastic test kit up with blue dye, then ran the car for a few minutes. I am not sure if this was what you were explaining. If the test stays blue, you are ok to change the water pump, but if the test fluid turns green, there is absolutely no bolt that can be tightened, and the engine is shot.

Again, this test will tell if the entire engine is shot, and will never let you know what cylinder is bad.

Possibly your intake was loose, and that was leading to a rich condition for the fuel issue? This is a completely separate issue from the coolant test.

I think you are going down the right path, just explaining it in a typed format is difficult. I agree with you that white powder around the water pump most likely equals a leak. Also make sure you maintain a 50/50 mixture of coolant. The waterpump requires a special tool made specifically for the N* to remove the housing. Also i think it os threaded in there backwards, so make sure someone who is familiar does thi, as doing it improperly will be very bad.

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sorry to correct but the engine is not shot. It is still repairable. the only engines that were shot were the ones wasted by the cash for clunkers BS.

If it runs it should definately be fixable, the question is how much time and or money do you want to spend

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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winterset that is exactly the test I done... but on the sheet of paper that came with either the kit or the blue stuff afer you did one bank at a time it told you how to determine the cylinders. Now I have another question,,, what is the best way to determine if the alternator is going bad. I know on the older cars you could always unhook th positive cable ad if the car stayed running the alternator as good. BUT several people has says you cannot do that on these newer cars? The reason I am asking is we took the Cadi through a car wash yesterday and my husband started to go to the store in it a couple of hours later and it just died on him. so I'm wondering if maybe something might be lose on the alternator ad the water didn't let it put out like it needed too or what? later this morning I am going to take the Alternator off ad take it to Advance or Auto Zone and hav it tested. The battry that was on the car was bad but it still isn't holdig the battery volts on this other battery either. So folks I need your help?

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I have read that Disconnecting the battery on a running car can damage the car electronics. If the alternator is bad, you will get a "battery no charge" message on the screen on addition to a battery icon. I would suspect either the stackable battery terminals on the positive side are dirty, corroded, or loose. Same for the - side being loose. If the battery is older than 4 years based on the battery date code, you should just replace it - especially if you don't know the history.

Removing the alternator is a royal PITA, and should be done in only the most extreme cases.

Was the replacement battery brand new? Was the replacement battery sitting somewhere uncharged?

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The Northstar does not have coolant flowing through the intake manifold - so loose intake bolts cannot be the issue.

Forget about changing the water pump at this point - they either pump or they don't - it is not the cause of overheating.

DO NOT unhook the alternator and run the engine - you will damage the electronics in the alternator. If the alternator needs replacing find a starter and alternator shop that can rebuild your existing unit. It will be cheaper and you will keep the chain store junk off the car. At this point, I'd sort out the headgasket issue before proceeding with any other repairs.

White smoke out of the tailpipes definitely points to a leaking headgasket. The engine can be fixed but it is up to you on how much you want to put into a 1997 car.

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

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I still think we are ok on this one. From the original post, the previous owners were running it with water, and the incorrect cap. Even a healthy engine would overheat in that environment. I also read the fluid stayed blue. The intake being loose might have lead to a rich condition causing smoke.

This is a new car patient, and there are alot of problems with the car, but we need to take them one at a time.

One point mentioned in the original post mentions the car overheats on steep grades. What exactly happens? Dos the temp clime to a higher temperature and fans come on? That is normal. Or does the red hot light come on, and the antifreeze pukes out the radiator cap - which is obviously very bad, and as mentioned needs to be addressed before anything else.

I understand the water pump is being changed because it is leaking, and there is white powder around the housing. If that is the case, to troubleshoot an overheating condition, the cooling system should not have any leaks, so that job is ok to proceed.

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A loose intake can result in a lean condition but it will not make the mixture rich. An overly rich condition will have black smoke out of the exhaust. Blue smoke = burning oil. White smoke indicates coolant is being introduced into the combustion chamber.

The fact the car is overheating on steep grades leads me to think the headgasket is in the beginning stages of failure. A leak at the water pump weep hole should not result in the car overheating - If it were me, I would verify the head gaskets were sound before dumping any more money or work into the car.

One way to positvely identify a headgasket failure is to pressurize each cylinder individually with shop air using a spark plug air adapter. The cylinder that is tested needs to be at top dead center. If you see any bubbles in the surge tank, the head gasket is leaking. This test needs to be repeated for the remaining cylinders.

Another way is to use a radiator pressure tester and pressurize the cold engine to the pressure listed on the radiator cap. Leave the tester on overnight if it appears to hold. In the morning, pull all 8 spark plugs, disable the ignition control module and crank the engine. If you see coolant being forced out of the cylinders, the headgasket(s) are bad.

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

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