changed the heater core now car running hot

First of all are you sure you have a sl1 and not a LS1?The SL1 model never traps air in the cooling system.But the LS1 trap air all the time plus the LS models i have changed tons of heater cores and the SL model barely have ever changed any.

I'm sure it says it on my title I just don't know why it's running hot now

Ok just making sure after my many years of working on saturns i have found a lot of customers are unsure of the model they have.I just dont want to waste time giving info on the wrong model.So does your ac work?If so turn it on does your radiator fan come on with the ac?Also how hot does the temp get?The radiator fan comes on just after the temp gauge goes past the half way mark on the gauge.Also the coolant is full?

Yes the a.c. works but it will come blow cool then it will shut off the fan does come on I don't know the accurate temp I know it goes to red it's full of coolant

Alright now were getting some where so the ac clutch kicks on and the radiator cooling fan doesnt come on?If so thats why its overheating the radiator cooling fan is inop.Do you have multimeter?

The fan does come the a.c. blows cold then starts blowing hot but the fan is working I don't know what a multimeter is

So the radiator fan under hood that attaches to the radiator comes on with the ac?Iam not talking about the inside blower fan that blows air into the car.

Yes that fan comes on I've heard it. I don't think it comes on when a.c. comes on thou

It should always come on with the ac if it doesnt it will cause the ac compressor to turn on and off.Try it now start the car up and turn the ac on make sure the ac compressor kicks on is the radiator fan on?It really sounds like your radiator fan has failed from your symptoms with the ac and the overheating unless your moving.

Ok started car turned on a.c radiator fan didn't come on had to turn it by hand to jump it. Then it came on so I need another radiator fan

So you spun the blade and the motor started spining?If so yes you need a new radiator fan motor.I figured from the symptoms thats what it was.Just a tip incase you need it alot of the aftermarket fan motors have whats called a torque ring on the back of the motor.That torque ring wont fit into the radiator fan shroud.So you slip the ring off install the motor then slip the ring back on.

Ok where is the fan motor located and how much work is involved

The fan is attached to the blade you spun its pretty easy to replace.Do you have a automatic or manual transmission?

Automatic I'm doing this job myself so I qant to be prepared lol

You will need to remove the air box where the air filter is you remove three 10mm bolts.Then you see a transmission cooler line screwed into the top of the radiator.Unscrew the line that takes a 1/2" line wrench to do that.Then keep the line up high to keep fluid from leaking out.Then unplug the O2 sensor screwed into the exhaust manifold.Then unclip all wires that clip to the radiator fan shroud.The remove the 10mm bolt from the top driverside of the radiator.Now the passengers side upper radaitor shroud just clips in.So pull the radiator up then pull it out towards the drivers side.Now unplug the radiator fan motor.Now remove the shroud from the car flip it over to the opening.Hold the fan blade with your hand loosen the 13mm nut clockwise its a left handed thread.Then remove the nut and blade.Real important when you put the blade back on the new motor make sure the pins on the bottom of blade go into the motors slots before tightening the nut.Now there will be three 10mm bolt hold the motor in place remove them now the motor will come out.Just a heads up when you put the fan shroud back in there are some hooks that hook into place on the bottom of the fan shroud.Let me know how it goes.

Ok I changed it.Its not running hot but now thie service engine light on I took it to autozone it said failed egr pressure sensor and intake air temperature signal open or shorted what does this mean thanks

Did you leave the sensor you unplugged from air box you removed unplugged?That would explain that would explain the intake air temp sensor code.Also i need the exact code numbers not code descriptions.Have the actual code numbers makes it alot easier to help then there is no guess work on my end.

It is p0404

Alright most likely for the egr code your egr valve is sticking you will have to remove the valve and turn it upside down.Then you will see a circle with a star in it that is whats called the pintle and what sticks.Get a small pocket screwdriver or similar tool that will fit inside the hole and is able to push the pintle down.Then slowly push the pintle down it should have little resistance when you start pushing it down.If its sticks at first and suddenly breaks free theres the problem and needs to be cleaned.But ethier way continue push it down and bottom out the pintle.Then slowly release the pintle did ut return closed or did ut stick open?Also before taking it off get a can of carb spray and some top engine cleaner the kind in liquid form that you pour out of the can.Etheir way were goiong to clean this valve.Also pick up a small oil drain pan to clean it in unless you have one already auto zone has some small black ones that are cheap and perfect to do this in.You can reuse the egr gasket.

Ok it worked thank you so much I couldn't done it with u thanks

Your welcome thats were here.So was the egr valve sticking and full of carbon?

Thanks! I have had the exact same things happen to my 2000 SL1 after replacing my radiator!

Your welcome that's what were here for.