When head lights are on, gauge drops near red zone goes up a little when rpm rises

do you haveck engine light onn

ford chevy what...

If temp gauge is going into the red on a 3.4 engine it must be shut down or head damage can happen within minutes. I have a Monte Carlo that was overheating. I changed everything, thermostat, water pump, belt tensioner, radiator, all with no result. It would start out okay on a cold start but then I would come to a red light and the temp would creep up. Higher and higher until it neared the red zone. The heat would run cold. Most of the time, as soon as it was about to touch the red it would start to drop, the heat would blow hot again and all seemed okay but not for long. This would get worse and worse until the red hot light came on and I found myself on the side of the thruway. This problem is a blown head gasket. I had no other obvious signs, no white smoke from the exhaust, no oil in the antifreeze. I even changed the intake gaskets. Head gasket issues are common on the 3.4 liter engines.

• One is the radiator and the other is an overflow tank. Sometimes anti freeze will back pressure a bit and need somewhere to go and other times the antifreeze gets low in the radiator. That is the purpose of the radiator.
• Put the antifreeze in the radiator fist and then add to the reservoir. Pay attention to the cold/hot level fill on the overfill tank.
• You need to find out where all that antifreeze went to if the radiator was empth. Pull the dipstick and look for a chocolate milk look on the oil. This would be a head gasket or a cracked head.
• Otherwise keep an eye out for a leak and repair it soon.
• Hope this helps and thank you for using FixYa.

Regards, Tony

This is a blown head gasket. get it fixed before it gets worst and destroys the engine. sorry

the drop- electric fan is coming on to cool the overheat- the heat- sounds like thermostat is bad-replace

The thermostat may be wearing out. A thermostat controls the engine temperature to keep it at a consistent temperature, The other fan will probably turn on if you turn on your Air Conditioner.

have the alternator and the battery tested at a local parts store, advance, auto zone or Oriellies the will do this free of charge.

Before getting too upset about this, try changing the temperature sender. Can't tell you where it is but it is usually on or near the thermostat housing but some engines have it on the intake manifold or rear of cyl head.

It has a leak. Fill up the radiator and the coolant tank. Then restart it and check for leaks.