cooling system

[Jon Burke]

I am having some trouble pinpointing the problem with my temperature gauge. Tt shoots from about ¼ to almost all the way to hot. The actual temperature in diagnostic mode went from 42° to 110° mirroring what the gauge was indicating. I removed the thermostat and the results remained the same. I was told by the previous owner that the engine temp switch was replaced. I cannot locate this switch. The engine does not appear to be operating significantly hot. Any input is appreciated. Thanks.

Jon

[Ronnie]

Welcome to the forum Jon!  Actually 110c, (230f), is within the operating range for the 3800 engine. You can sometimes see that when sitting in traffic on a really hot day. Can you tell if both cooling fans on the radiator are turning on high to cool it back down?  You shouldn't see that spike in temperature when driving down the road with plenty of air flowing through the radiator. If you do something is wrong.

[2seater]

Engine temperature sending unit is on the driver’s side end of intake manifold below the throttle body. The information from that single sender is used by the ECM to operate the cooling fans as well as the IPC display.

[Jon Burke]

Thanks Ronnie. That spike is an all the time occurance, warming up in the driveway or driving down the road at any speed, and appears to be prior to the thermostat even opening (no running river apparent with the radiator cap off). The cooling fans come on at the same time as the spike. Like I said, temp goes from  42° to 110° displayed from ED04 diagnostic with nothing in between, even with no thermostat installed. Something is not right. I will try another sending unit now that I know where to look (thanks 2seater).

[Ronnie]

I think replacing the sending unit would be a good idea. Be sure to get the correct one for your Reatta. The one in there now might not be the right one for your car.