First Time Caddy owner

[infamous805187]

I just bought a caddy 93 sts, and it is a jet. I barely touch the pedal and Im going 80. Every time I get on the freeway I am surprised by how i leave every car in the dust without even trying to. However, when I am in the city i dont give it any gas and I get up to 20, i cruise the city without giving it gas, is this normal, It says its only getting 11.5 mpg when i do this. The car has an oil leak as I read is normal for this model, but every time I stop after cruising around, i smell the strong smell of coolant, but im never low?? The car also reads to be at tempuratures over 200 F. Is this normal? any advise would help. I still have to smog it, will the oil leak or the coolant smell prevent it from passing? thanks a lot. this site is awsome. I dont know why I ever bought an eclipes, this caddy blows it away...

[Bruce Nunnally]

Congrats on the new car. The 93 STS is a special car, the best expression of the touring car suspension and concept and before the exhaust got toned down a bit later.

200F is no problem with the cooling system; the high speed fans come on at higher temps than that.

You have to reset average MPG for a stretch or period you want to measure through, otherwise it is cumulative since the last reset.

You should not be smelling coolant; that suggests you have a coolant leak, or that the system is not maintaining pressure.

[BodybyFisher]

I dont know the 93 NS too well to solve your problem but it sounds like your idle is too high because of your statement that you can do 20 without touching the gas. When your car is in gear with the brake on, what is your RPM? It should be about 625 to 650.. Mike

I think the early NS's had ISC (idle speed) motors, if you are idling high that may be the cause... but it may just be that your throttle body needs cleaning...

Check your computer codes and post them here, see this link on how to read your codes:

http://www.caddyinfo.com/readingcodes.html

[Ranger]

210-220 is about normal operating tempurature. If you smell coolant, you have a small leak somewhere. Remember, the '92 used green coolant and needs to be changed every 2 years. Don't forget the sealant tabs (cooling system suppliment).

11.5 is way to low fuel economy unless you have your foot in the TB all the time. Maybe a leaky FPR. For the high idle, your probably due for a good TB cleaning.

[Poobah]

As my mechanic once put it, those early Northstars run like a raped ape!

All kidding aside, your STS should get much better than 11 MPG. My '94 Eldorado got about 19.8 MPG. The STS is geared to let the engine run a bit faster at the expense of some milage but I would expect you should get about 19 MPG more or less. To reset the milage computer, press the INFORMATION button several times until the read-out at the bottom of the instrument cluster reads, "AVERAGE MILAGE XXX MPG" then press and hold the RESET button until it resets to 000. Give the car a week or two for the milage figure to stalilize and it will give you a true milage reading for the type of driving you do.

As for oil consumption, your engine probably does have leaks, most older engines do. In all likelihood, they result in minor seepage that results in a drop or two on the garage floor - nothing to worry about. Northstars tend to consume oil, however. This is due to a rather agressive hatch pattern on the cylinder walls. This was a design decision that Cadillac made. It keeps the upper piston rings well lubricated and allows many Northstars to run 200,000 miles and more without an engine overhaul. It is not at all uncommon for these engines to consume up to a quart of oil every 1000 miles.

Enjoy your Cadillac and welcome to this forum!

[pos2nat]

I also have a 93 STS. I recommend changing your coolant, use a 50/50 mix and add the sealant tabs. The coolant smell may come from a small leak which the tabs will take care of. Your running temp in summer should be between 208 to 225, on hot days in traffic it may go up to 230. Low speed fans come on around 225-226 and high speed fans at 232-235. The digital readout normally goes down to 217 then up again to 225. I also recommend changing the thermostat with an OEM one while you're changing coolant. When next you change oil, don't overfill. The system needs 7.5 qts. Check oil when engine is hot for best reading. If you check it cold, you may feel the need to add oil. Enjoy freeway on ramps, drive it like you stole it.

[growe3]

With "normal" driving, you should get about 19.6 to 21 MPG on the freeway (fairly steady cruising at 75 MPH or so). Around 17 to 18 MPG, for in-town stop and go driving. As you know it is fun to hit the gas, but this will really lower your in-town mileage.

This engine likes to be driven, not puttered about town. The Northstar is designed to routinely operate at much higher RPM’s, and temperatures than most V8 engines.

Occasional WOTs are good to keep the engine from building up carbon deposits in the combustion chambers. When going off the freeway, or decelerating down hills, drop it into third gear. This helps keep the rings free and will keep the oil usage minimized. A quart of oil in 1500 miles is quite normal for the Northstar. They have a very aggressive cylinder hone, to keep the pistons well lubricated. The upside is the cylinders virtually never show any wear, the downside is adding oil every 1500 miles or so.

Change the oil when the oil life monitor indicates it is time. This is an excellent, and well proven monitoring device, trust it.

Important point on oil, this engine takes 7.5 quarts for an oil change (including filter of course). After an oil change, the dipstick will show about 1/2 quart low, this is normal. If you fill until the dipstick indicates full, you will just burn off the first 1/2 quart quickly.

Check the oil weekly, and add (1 qt.) when the oil is just at the bottom of the dipstick.

There is no need to use any synthetic oils in this engine. A good quality 10-30 works just fine. I have been using Pennzoil on both of my 93 STS’s for several years, other name brands should also be fine.

Some small seepage is also “normal” from the oil pan area. Unless you can see oil dripping when the engine is running, there is nothing to worry about.

A primary cause of head gasket failure ($$$$) is not changing the coolant every two years.

If you have not done so, change the coolant!

Drain the coolant as throughly as you can, do not flush the system.

Loosen the clamp at the upper end of the lower radiator hose, and add two tubes of Bars Leak Gold; DO NOT ADD TO THE SURGE TANK. Replace hose and tighten clamp.

Refill with the green type coolant, premix it to 50/50.

[infamous805187]

Ive really been enjoying those freeway on ramps, nothing like being pressed back into your seat

. Does anyone think i would have trouble passing the smog with these issues?

RE:growe3, my car looks just like yours but with different rims. thanks a lot

[BodybyFisher]

That is hard to know without seeing if you have any codes... Most states fail cars if they have PCM codes.

[rollingthunder1994]

Curtis,

Where do you see your oil leak comming from? I had a oil leak a while back when i took my car for inspection. The mechanic told me it was coming from the hlf case draining on the frame to toward the front, They quoted $2000. Turned out it was a bad balancer pulley, that was ccutting into the tming chain cover causing it to leak oil. Got a new timing chain cover, balancer, seals, for $180, and it was put in for $250. No more oil leaks. Where do you see your leak at?

[infamous805187]

its hard to tell where the leak is coming from because it seems to be just one drop each time I stop, literally just one drop. I check the oil constantly and its full and looks brand new. I dont know if I should be too worried, maybe its overfull? or maybe it isn't even oil. I noticed that the car doesn't start too well when cold, I have to floor the gas pedal, isn't this a condition of a flooded engine? maybe its gasoline, its really not enough to even smell. I guess I could taste it...

[BodybyFisher]

One drop? Count your blessings and keep driving it... These engines can be bigtime leakers, you are doing great.

Check your Fuel Pressure Regulator, I am not sure where it is on a 93 or how it operates. Flooring your pedal shuts off the injectors and typically clears a flooding condition.

You need to check for computer codes as we are flying in the dark without them, I posted the procedure on how to do it above...

[Ranger]

The FPR on a '93 is inside the intake manifold. Just remove the top cover. You'll see it atached to the fuel rail. Turn the key on, but DO NOT start the engine with the cover off. If fuel leaks out of the nipple, replace it.