why is my gmc suburban temp gauge fluctuating

How fast does it fluctuate? I mean does it slowly go in to red then back down, or suddenly jump up there, then flip back to middle? You seem to have done all the right things, a 4 year old radiator should be in just fine working order...it could possibly be the sending unit, check the connection to make sure it is secure. Or just replace it, it is not expensive

it fluctuates slowly and at times stays in the normal position had a feeling that it my be a sensor or something, will let you know how i make out and thanks

Please do. Let me know that is. And if you click on the image ....the drawing.. it gets bigger so you can see it.....David

put the new sensor in and still having the same problem, i also replaced the radiator cap for the heck of it. this is starting to drive me nuts! any suggestions? thanks

I have same problem with my 99 suburban. U ever figure out?

i think i have. noticed this past summer that everything was normal but when i started turning the heat on this fall the gauge would start to fluctuate if i turn the heat off the gauge goes back down to normal so i believe it's the dash switch. hope this help's you out.

no one ever found out why this is so? my 94 k1500 Blazer does the same exact thing...

Had something similar changed the temperature sensor and noticed that the prongs on the sensor were slightly cocorroded. ..I plugged it back on without cleaning the female plug and it was still hesitating and temp gauge was spiking. . I took some electro clean and a small rat tail file cleaned it up good.. Problem solved. . Hope this helps. ..

I have the same prob on my 97 Yukon. I had a 93 Camaro with similar prob. Must be a 90s chevy defect. Neither car acted different, just the temp gauge and check gauges light.

I have a 05 suburban that does the same thing and I was told it was the fan clutch

I have a 1976 chevy suburban C10 350 5.7ltr 8 silinder with a overheating problem. Replaced the waterpump today and got a New thermostat but still get overheating (in less then 15 minutes)

And my temp gauge allways jumps from cold to Hot, like a maniac. It bounces sometimes looks like a ventilator

Same problem here. 08 yukon, replaced coolant temp sensor, temp gauge still bounces from normal to hot multiple times while driving. Purged any air out of the coolant as best I could. Dont know what could be the problem, this morning I started it and it immediately the temp spikes and goes back down it was cold! Any suggestions?

OMG, I started having the same problem in my 07 Escalade whenever I turn the heat on. I'm taking it to the shop today, I'll update with their findings...(praying for an inexpensive fix)

I bought a 1999 Chevy C3500 couple days ago, drove it from Vegas to Denver while my check gauge light and the temp gauge on the dash said the engine was running super hot, it wasn’t of course or it would’ve blown coolant out or not made it the 11 hours here. I changed the thermostat, the temp sending unit, the temp sensor and still have that problem. Any suggestions?

Hey all, I was having the same problem. 08 yukon temp gauge fluctuating many times during my commute to work. Truck would go into low power mode for a second each time too, and information center would say, idle engine. Yesterday I changed out all 8 spark plugs, which looked pretty bad. Today, no temp fluctuation. Yukon drives perfectly without any error messages. I'm guessing that the problem is electrical and bad sparks can send mixed messages to the ecm. Try for yourself and see what happens. I will update again shortly. Pete

I'm having the same problem I changed out my out my alternator,waterpump,temp sensor and also radiator it's still getting hot and goes back to 210

No on the spark plugs. I have an 05 duramax Diesel and temp gauge does same thing. Motor is not hot, but gauge swings wildly at random times. Replace sender unit, but problem remains. Bear

Drove my 98 suburban 450 miles on I-70 without a problem. Then suddenly my temp guage started reading hot. It took a few mins to cool while still driving. Now it fluctuates quite rapidly while driving anywhere. Iv read it's a symptom of a bad catalytic converter, which is the only code coming from the Check engine light. It runs about 800 bucks with labor included here in s.w. Kansas. I will likely try the serpentine belt and tensioner pulley first which is also needing replaced. Then if that dont help it the temp sensor will be next. I'll update afterwards. Best of luck to you all.

Hmmm. wonder if 6veinte has something, 2004 Suburban,my Check engine light went on and code read was oxygen sensor- for about 2 weeks- then 2 weeks later or so light went out after putting octane booster and premium gas, BUT 2 weeks later going from 210 to 250 temp randomly for no reason..wonder if I should have changed oxygen sensor....because could be effecting catalytic converter ? wow, help I want another 50 K ! Only have 183, lol

I have a 01 chevy tahoe with the same problem but my fan is belt driven not a clutch fan my problem was not the temperature sencor itself but the plug that connects to it was loose i replaced it an the problem has stopped this is twice it has done this in the 9 years ive had the vehicle i hope this helps

1997 k1500 5.7 vortec (spider injection) There are 2 different temp sensors on my truck. One right in front of the thermostat (2 wires) and the other down by the #1 spark plug and exhaust manifold (1 wire). From what I've researched, one of them is for the ECM (2 wire) and the other is for my guage (1 wire)

Mine was doing the same as everyone else found the wire on temp sensor ( single back wire) by number 1 spark plug shorting out against head.. taped up spot on wire and zipped tied away from head and problem was fixed.. check for short before replacing anything!!