Emission control light on

SOURCE: 1999 Cadillac coolant leak,can not find

ok...here is my experience with our 1999 Deville. We had the same problem with ours almost 8 months until we had the coolant flushed and filled. That is when our problem reared its ugly head. As you probably already know, this Northstar engine does have well known issues with head gasket failure as well as head bolt issues and last but not least, thermostat problems. If you haven't had an "official" overheat ( not just the coolant low light, but a true blue overheat where car has safety to shut down or run on half the cylinders) you should be fine and your engine healthy enough to repair.

I would dare say it is your head gasket. The first thing you should do is pressure test your sytem, this will diagnose whether or not it is infact your head gasket. It could also be a head bolt(s) that pull from the block when car gets too hot. If either of these things are the problem, be prepared for the investment and be sure that whoever does the work on your engine knows how to diagnose whether your engine is good enough to repair. Cadillac service bulletins instruct dealerships to replace the engine in this case, but you can repair an engine that is healthy enough. It is costly and you must love your car, but if the love is TRUE, you will love it more when it is repaired.

You did mention that the oil is fine...I know you wereprobably looking for coolant.....when these head gaskets go, the coolant doesnt necessarily mix with the oil, in fact, we didnt have that problem at all. Our coolant was shooting out the tailpipe and evaporating. You could probably check your spark plugs for coolant residue, but you would have to be sure to check them all, because you will probably have the problem in only 1 cylinder. The best way to get a yes or no is the pressure test. Good Luck!

SOURCE: 1979 cad fleetwood brougham knocking sound from,engine

Sometimes collapsed lifters or loose rocker arms can cause knocking sounds in an engine. However, the fact that there was a possible loss of oil pressure and that the knocking gets louder as the rpm's increase, would indicate that there is damage to a connecting rod bearing and possibly the crankshaft. If the latter is the case you are looking at a fairly substantial repair bill.

SOURCE: 98 Catera goes into "Limp Mode" after warm up.

have you check you ignition coil packs.

SOURCE: have 96 seville service emission system is displaying,

Turn your key to the On position ( don't start it ) now, on your heat/air panel, press and hold the OFF and the WARMER (red) buttons at the same time for about 8sec. You will see your dash light up with every segment lit, you can let go when it starts. Then you computer will run its diagnostic check for error codes. Have a pen and paper ready to copy them down. As a guess, I bet it's going to throw a O2 sensor code. Let me know the codes. After that just turn your key off and your done with that portion.

SOURCE: 1997 cadillac deville- misfires on cylinder #1

It sure is. If a plug is truly wet, the energy for the spark will travel through the moisture, rather than across the gap. The fuel air mixture flowing into and out of the cylinder serves to ventilate the cylinder, drying the plug.

Plus, that air is preheated, so that would accelerate the drying once warming up got underway.

You really need to have that head gasket replaced. If this questionable repair gives way (and it almost certainly will), you can get enough water in the cylinder to start breaking things on startup without any warning.

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