biglg

My 2007 tahoe takes forever for the engine to heat up. The outside temp has been around 45-50 degrees. The tahoe was parked outside overnight. It took over 12 minutes of driving for the engine to heat up to normal operating temp. In fact the needle never moved for at least 7 minutes of driving?

Is this normal? I cant believe it takes this long. Is something wrong with my sensor?

digdug

My Av warms up pretty quickly. Especially when I remote start it beofre I get out there.

Seriously though ... I'd say it takes 4-5 min. tops for me to warm up at approx. the same temps outside.

~digdug

73shark

Check the thermostat. It has to be completely closed at ambient temp.

biglg

I drove about 5 miles, 7-10 minutes in the city to get gas Saturday morning. I stopped filled up and headed home. I was almost back home and the temp needle had just started to move, truck was maybe 100 degrees after 15 minutes of driving. The next day we were headed on a road trip. I had been driving for at least 10-15 minutes and looked at the tahoe temp and the needle had not moved???

73shark

Have the heater on high and see if it warms up faster than the temp gauge indicates. If it does then it might be the temp sensor or temp gauge. If not, then probably the t-stat. Surprised if it really isn't heating up any faster that you aren't getting a "check engine" lite.

biglg

ZX/Dave,

Do you have an opinion here? NOrmal, abnormal? What to tell the shop?

ZX1100F1

After about 10 minutes does the temp gauge read just under the 210 mark? And does it stay pretty stable once it gets there?

With temps that low it is definitely normal for these 5.3L motors to take a while to get up to normal operating temperature, they are cold blooded.

When the switch was made to the dual electric cooling fan system the rest of the cooling system had to be made so that it would dissipate heat much more efficiently.
Also, in years past we used systems that would get the engine up to operating temperature as quickly as possible to reduce pollution but the new 2007 Tahoe uses a new style of catalytic converter, technically known as the “Close-Coupled Catalytic Converter”, providing quick catalyst warm-up resulting in lower tail pipe emissions earlier in the vehicle operating cycle eliminating the need to artificially get the engine up to operating temperature quickly.

If you feel that your truck is not warming up as quickly as it should; and you have verified that by checking that temp of the air flow with the heater (turned to full hot), then the only thing that could be causing the problem is the engine thermostat, have the dealer check it out.

biglg

Dave,

I would say at 10 minutes of driving the temp gauge hasnt really moved yet, it might show the needle has slightly moved upward. I would estimate more around 15 minutes it finally gets to 210. Once it gets there it is pretty stable. It stays around 185-210. What is the thermostat temp in the 07 tahoes?

Thanks again for the reply.

ZX1100F1

The stock thermostat is a 195 and I have rarely come across a bad one.
15 minutes sounds like a long time though, but are you doing city or highway driving?
It will warm up faster on the highway, there are so many variables.

How long does it take for the heater to start to blow noticeably warm air?

biglg

Dave,

I actually notice it to be about the same whether it is down the highway or in town. I will say that it takes noticably longer than any other vehicle I have had.

As for the temp of the air out the vents I would say that it gets "warm" way before the needle moves. However it obvoiusly isnt hot until the needle is around the 200 setting. The heater gets warmer as the needle moves.