1991 Buick Regal will not start on cold mornings. Battery has been replaced. What else could it be?

Take your starting modulator in for testing. Make sure a pat test is performed. Pat test are to see if bouncing down the road is causing problems.

Your battery could be weak, Do you still have the original battery? You can get a new one at basically any auto parts store.

sounds like your alternator could be givin up slowly, have a charging test done and after a full charge on the battery have it tested as well.

egr valve is not opening up when the engine reaches it normal operating temperture

Sounds like a dead cell/shorted battery. 3 years is a little soon but with the fact that you recently replaced the alternator, I would suspect that your battery is done! Even a weak battery will let you jump one, bad cables usually will let you jump one, but a shorted/bad celll in a battery will prevent them from taking a jump. good luck

just had same problem with 2000 Buick regal , the thermostat was stuck open just a little , just enough so coolant didn't get hot ,so heater doesn't get hot .. not good on cold mornings !! temp gauge never went more than a quarter, should have been almost half

starter relay or bad battery

I had they same problem a few years back. Aging electronic circuits may be the issue here. That is what happened to cause the remote door feature to operate intermittently in my 1991 Buick Regal. Over time the heat of summer and the cold in winter stress solder joints on printed circuit boards. That stress can bring about what is known as cold solder joints.

I located the remote door receiver module behind the back seat under the cover that holds the Third Brake Light. Once removed from the car I opened the module up and inspected the printed circuit. Sure enough I saw the problem using a magnifying glass. Many of the solder points had cracks around connectors, resistors, capacitors to name a few. Resoldering each bad point sovled the intermittent operation. I hope this helps...

It probably has an airlock - so needs the air leting out of it.

If you have the bleed screw on the pipe that goes from engine to bulkhead, then, with engine cold, and heater turned to heat, start engine( KEEP CLEAR OF FAN / BELTS ), and undo bleedscrew to let out air. STOP ENGINE. Refill coolant to mark with antifreeze mix.

If this soes not solve problem, it could be more serious - either blocked matrix or if you only find steam regularly - it's a head gasket problem - requiring replacement.

check the batt. connector