Main IndexAuto Repair Home Search Posts SEARCH
Who's Online WHO'S
Log in LOG

99 Chev. Tahoe Temp Gauge???

  Email This Post

New User

Oct 15, 2008, 11:49 AM

Post #1 of 6 (1374 views)
99 Chev. Tahoe Temp Gauge??? Sign In

I have a 99 Tahoe with 180,000 miles with the 5.7 V8. My temp gauge has been acting kind of odd lately. If I drive with no heat on and the temp turned to cool (but still on OFF), the temp gauge goes to normal temp while driving. If I turn the temp dial to HEAT or WARM or do this and actually turn the heat on, the temp gauge starts to go down and cool off. My truck has always showed the temp gauge at the same temp for years while driving, idiling, heat or A/C, now it's been doing this. Do I just need to replace the thermostat or is something else going on? It's running just file, but seeing a different temp than usual it what concerns me as winter is approaching rather fast here in MN!


Oct 19, 2008, 1:33 AM

Post #2 of 6 (1361 views)
Re: 99 Chev. Tahoe Temp Gauge??? [In reply to] Sign In

replace thermostat and do flush. make sure you use flush additives with the heater wide open this should take care of your problem.

Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Oct 19, 2008, 6:53 AM

Post #3 of 6 (1353 views)
Re: 99 Chev. Tahoe Temp Gauge??? [In reply to] Sign In

Agree with T-stat and flush. I think what's happening is that thermostat isn't closing tight and some residual cooling is happening at the radiator unneeded AND with the added heat lost to heating interior the temp actually drops. Heater really is a mini radiator itself.

Good that you take notice of these things. Temp gauge should read the same spot year round with only the wildest ambient temp extremes make it nudge higher or lower within norms,

Long retired now

Anonymous Poster

Oct 19, 2008, 5:23 PM

Post #4 of 6 (1347 views)
Re: 99 Chev. Tahoe Temp Gauge??? [In reply to] Sign In

I think with the temp fluctuating i would also keep a close eye on the oil, at 240F these seem to cook intake gaskets. A bad ground can also drive your gauges wild.You may also want to check or replace the temperature sending sensor.

New User

Oct 20, 2008, 1:36 PM

Post #5 of 6 (1335 views)
Re: 99 Chev. Tahoe Temp Gauge??? [In reply to] Sign In

Thanks for the info. That's what I thought, but just wanted to double check. I have not replaced a t-stat in while. Any idea how much they run for price and installation? It has always read the same temp year round until recently with the colder weather here in MN and I had to turn the temp/heat on to WARM.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Oct 20, 2008, 5:34 PM

Post #6 of 6 (1330 views)
Re: 99 Chev. Tahoe Temp Gauge??? [In reply to] Sign In

I don't know of a life expectancy for T-stats but we tend to toss them when we are in there for things and also needs to be removed for flushing.

This one if fairly straight forward and thermostat + gasket are resonably cheap and on the DIY list if that's you.

However - it's a good opportunity to check hoses and those aren't so cheap but don't short yourself. OE clamps are funky but can do with good plier assortment if your are handy or there's a tool that costs way 2 much for those.

Know that this 5.7 was known for intake gasket leaks and that's a job if not done yet.

Prices for labor: You just have to ask locally what they want for this service. Parts you can just Google your local outlets or call them. If you send it out the shop should get their own unless you have an agreement and shops do charge "list" price for parts but are taking responsibility for them too.

Suggestion: Keep it 50/50 anti-freeze which = -34F protection but it's really ok if it get colder overnite at just that and no more. The mix would only be slushy and not break parts if you do experience colder temps - we do in NH here routinely. Too strong isn't good for the next Summer's cooling needs. Also IMO forget DexCool (Gm's trademarked anti-freeze) and just used guaranteed universal lifetime anti-freeze now boasted by Peak for example and color doesn't matter. I'd still change it once in a blue moon anyway.

Stay warm. Already been in the 20s here west of Beantown,

Long retired now

99 Chev. Tahoe Temp Gauge???

  Email This Post

Latest Forum Post

I start my car in the morning and it immediately dies. I start it again and befo...

Have a 2002 buick lesabre auto tranny with a 3.8 engine that would have heat and...

I have a 1996 Chrysler Sebring that is overheating.. I would hear it bubbling b...

I had my pickup at the chevy garage 6 months ago and got new plugs, wires, and r...

I really need help with this one. I've got a VW Polo 1.2 9N 2003 and recently ...

Hello. We are working on a new OBD II tracker/scanner. Our device is almost fini...

Feed Button

Automotive Forum Categories
AC Auto Repair
Auto Body Repair
Auto Insurance
Automotive Repair
Automotive Wiring
Automotive World
Brake Systems
Car Care Tips
Car Racing
Car Shows and Events
Car Stereo Repair
Car Troubleshooting
Engine and Car Noises
Engine Fault Codes
Engine Troubleshooting
Exhaust System Repair
Gasoline and Motor Oils
General Discussions
Motor Vehicle Inspection
Motorcycle ATV Repairs
Motorcycle Body Repair
Motorcycle Clutch Repair
Motorcycle Engine Repair
Motorcycle Repair
Motorcycle Seat Repair
Remote Control Cars
Steering and Suspension
The Bargin Bin
Traffic Ticket Help
Tricks of the Trade
Truck Repair
Truck Repair Advice
Truck Engine Repair
Truck Suspension Repair
Car Forum - Sitemap

Search for (options) Privacy

web statistics