20 Most Recent 1998 Cadillac Seville - Page 9 Questions & Answers

The test light really won't isolate the problem. You will always have some draw because of the radio memory and the security is alway on when the key is out.. What you need to do is use an amp guage to see how many amps are being drawn. Normal with key out of the ignition after a minute or two ( the BCM ) computer needs time to shut off, there should be no more than a 1/4 amp draw, or .030 give or take.. If you have a couple amp draw then its possble you have BCM issue or because your staing the heater blower motor is the circuit you messing with I would suspect the blower shorted internally. Its pretty common for this to happen. If you unplug the blower motor and the amp draw goes down , then you found the system with the problem. The problem could be the blower motor or the climate control unit.

Also its possible you just have a bad battery. Hook up a 12v meter and while cranking look at the voltage. It should not drop more than 1/2 volt.

Even a perfectly good TESTED battery can still not hold a charge over a short period of time. Cold is usually when batteries fail.

if its in anti theft mode unfortunatly you will have to go to gm dealer to get it reset

its near the center or passengers side center inside the duct work boxes actuator is on the top outside box wayyyyyyyyyyyyyyyyyyyyyyy under the dash

Fuse has blown in the heater control unit, I had this on my audi last year most likely cause, get youe user manual and loacte the fuse box.

use gas treatment, i like stp concenstrate. in a black bottle. run a couple of bottles thru. one at a time of course. bottle recomends gas tank to be full. but i have used gas treatment with 1/4-1/2 tank of gas. it works

HI There
Yes you are right. Your going the right direction. You just need to take it off and replace it. Make sure you clean it real good before you put on the new seal. Just a reminder. So let me know how it went and i know you will do a good job. Thank you for writing to fix ya.
Best Regards Richard

if you replaced the starter with a remand unit it could still be a bad starter(personal experience),but if your battery show 12v only when being jumped your battery is having issues,take the battery and have it checked if it was replaced before the starter it could have problems due to the starter drawing to much at once and not recovering,and also have the alternator checked out this will kill a brand new battery very quickly even with nothing on.

11.3 volts is a good indication that the battery needs replacing. a boost should start the car with a good connection at both ends

If it smokes out the exhaust it is a head gasket.If it is smoking in the engine area then look to see where it is leaking coolant on the engine.

TO CHANGE A HEAD GASKET IS SKILL LEVEL B MEANING YOU MUST HAVE BASIC KNOWLEDGE OF COMPLEX SYSTEMS.ITS A HARD JOB IF ITS YOUR FIRST TIME.THIS IS A DEALERSHIP JOB BECAUSE MANUFACTURER RECOMMENDS THAT THE ENTIRE POWERTRAIN BE REMOVED FROM THE VECHICLE.BEFORE REMOVING THE CYLINDER HEADS.

Did you burp the cooling system after changing those parts? If not, you have to. Jack up the car so that the thermostat is pointing upward, and start the car. Let it run until it's 3/4 of the way to overheating. Then shut it off and let it cool. When it's cooled down and safe to open the radiator cap, do so - this will burp the trapped air bubbles out of the system. The coolant level will go down, now that the bubbles are gone, so top off the coolant. You may want to do it a second time to be sure, and then you should be set. If not, you have more serious issues (potentially bad head gaskets, for example).

When this happens and the key is in the Ignition position, do the dash lights, etc come on? Could be the ignition switch is bad, and this is and easy way to tell. If the ignition is on and when we go to START, nothing happens, I would replace the starter/solenoid next.

have you replaced the battery.

The most common overheating problem with the Northstar engine is a blocked purge line. It's job is to purge air out of the cooling system.
If the purge line is blocked you may have an air lock preventing coolant flow.
There is a small diameter hose coming from near the top of the coolant tank,this is the purge line.
With the engine idling,pull the purge line from the tank,if there is no coolant flow from this small hose,it is blocked and this will cause overheating.If the hose is clear, check for blockage at the nipple on the tank.

Air locks in the Northstar engine shouldn't be a problem as the system is self purging, providing all the hoses are clear.

Check the coolant level in the tank,it should be half way when cold.
There is no cap on the radiator as it is a fully pressurized system.

The expansion tank is the only means by which to add coolant to the Northstar engine.

Check to see if your fans are working by switching on the air con,they should run all the time.

With the air con off,the fans won't come on until the temp hits around 225 degrees.

Also, if it's boiling over, the cap on the expansion tank may not be holding pressure and therefore needs replacing.....a new cap only costs a few dollars so it is worth replacing to see if this solves your problem.

go to autozone.com and register for full free online repair manual with everything you need.

u need the owners manual. it tells how to change the theft deterrent system.

Check for coolant flow at the Purge line,this is a common problem on the Northstar.
There is a small diameter hose coming from near the top of the coolant tank,this is the purge line.
With the engine idling,pull the purge line from the tank,if there is no coolant flow from this small hose,it is blocked and this will cause overheating.If the hose is clear, check for blockage at the nipple on the tank.

have the battery tested, a shorted cell in the battery can cause an overchargre (anything over 15 volts) condition, also verify at the battery that the system charging voltage is 16 volts.

Why do you suspect overheating? Give us a lot more,past problems,repairs and what symptoms you have.

Have the battery checked out at Sears auto are a large auto parts store. They do it for free.