Inaccurate temp gauge(searched)

I've read 3 or 4 other threads on an inaccurate gauge but still have a question...96 4.0 AW4

Thought it was overheating in traffic at idle because the temp would go up from right under 210 to in the red, Radiator new, replaced thermostat, same deal

My mech. hooked it up to a machine since its OBDII and said the temp never got over 217, question....

Is it possible for the gauge to only be reading inaccuratly at idle or in traffic?

Why would it read right under 210, which is correct, until Im in stop and go traffic etc?

http://www.toolsource.com/ost//prod...6668&mscssid=P0SQN2TUV8R98G91VQXW4UKW5WGU0P26

Nice and easy with a digital heat gun. A mechanical gauge can also do the trick. Place the probe in a hose connection that's easy to get at. Usually the connection at the thermostat housing is good. You can also check to see if the thermostat is sticking at the same time. Good Luck

Woody

Ok thanks, It might be hard to get a reading in traffic haha. I know thats how I can check, and I will this weekend.
I trust my mech. with the reading he gave me,he spent over an hour with the jeep.

I just don't get how the gauge could only be inaccurate in traffic/at idle, can anyone explain that??

The guage reads temp at the back of the head. ODBII sensor reads temp at the thermostat housing.
Wayne

EBXJBOB said:

Ok thanks, It might be hard to get a reading in traffic haha. I know thats how I can check, and I will this weekend.
I trust my mech. with the reading he gave me,he spent over an hour with the jeep.

I just don't get how the gauge could only be inaccurate in traffic/at idle, can anyone explain that??

Click to expand...

Possibly a bad collant temp sensor (the one at the bad of the head).

Here's a test procedure from AutoZone:

http://www.autozone.com/servlet/UiB..._us/0900823d/80/15/23/1a/0900823d8015231a.jsp

When you were driving the hood was closed,... I bet your mechanic tested it with the hood open. That could make a difference.

yardape said:

When you were driving the hood was closed,... I bet your mechanic tested it with the hood open. That could make a difference.

Click to expand...

The OBD II can in many cases store information so you don't even have to have the vehicle running to check it out.

drewkeen said:

The OBD II can in many cases store information so you don't even have to have the vehicle running to check it out.

Click to expand...

Fair enough, but just mentioned this because if the mechanic did try and replicate the overheating condition, the hood situation may have been overlooked. It happened to me. As soon as the hood was closed the temp went through the roof.