Two extremely cold mornings (-3F and -6F) here in Park City, Utah have made my 06 taco make a strange noise. Immediately after she turns over for the first time of the day (only) I hear a strange noise for about 1 second. It sounds kind of like an impact wrench, but not really, and not that loud...

Anyone else have an extra noise coming from thier 4.0 on really, really cold mornings?

Maybe it is the ABS pump? That thing was noisy in my 4runner. Although, I have only heard the Taco make this sound on two cold start ups, and the 4runner would make the pump sound quite often. Cold and high elevation seemed to make 4runner sound louder and occur more often. My house is at 7,000 ft and I am pretty sure this made the pump work harder and more often.

Anyone hear nothing from thier 05/06 4.0 on super cold mornings at high elevation? That would suggest I have a problem.

I have heard that noise too, and here is how I can reproduce it easily. Leave the truck sitting for several hours. Start the motor and let it run for about 5 seconds, then turn it off. Wait overnight and the next morning start the truck. Presto I get that noise. It lasts a few seconds then goes away and the truck runs a little rough whlie it's making the noise. From what I can tell it's a valve sticking open a little. It would be great if someone else could try this same thing and see if they get the same results.

Damn -6? Geeze I didn't know anything would start in that cold!? Do you use 0w-30 oil? I'm in S. FL so anything under 70F is cold here..

This may be a dumb question, but if it's that cold are you sure it's not just your rockers tapping until the cold/thick oil get distributed? <img src="/forums/images/graemlins/confused.gif" alt="" />

...Anyone hear nothing from thier 05/06 4.0 on super cold mornings at high elevation? That would suggest I have a problem...

Did it occur to you that maybe no one has a new truck? <img src="/forums/images/graemlins/shame.gif" alt="" />

You might need to switch over to 5w30 or synth for the winter. Heat pad on the oil pan is also helpful. Engine starves the first few seconds if the oil is cold enough. Heat pad or proper weight keeps it viscous.

Check your owner's manual for recommendation.

I would only expect that with hydrolic lifters. The 3.4L does not have hydrolic lifters; I forgot what motor the original poster had, but does it have hydrolic lifters?

Maybe it is just too damn cold! I just started our Honda Civic, which is loaded with Mobil1 0W20 full syn, and it sounded like there was cement in the oil pan! It started but then made bad noises for nearly 10 seconds! We are having near record low temps, so hopefully these issues will pass. Weather.com said it was 0 degrees F this morning - felt colder than that. Might need to get some heat on these engines.

Damn, it was 75-80F today. I had to run the A/C on my way home from work to keep from sweating, and the sun isn't even out. 0F is insane, I don't know how you guys do it.

You guys make me laugh; I'll be out in my driveway working on my truck this next week with a parachute and a space heater.

I was stationed at Eglin AFB before coming up here; zero will kill off a few bugs at least! <img src="/forums/images/graemlins/lol.gif" alt="" />

If you can't find heat pads for the oil pans, you might look for some of the magnetic ones you can remove. Just don't put them on a leaky mill, or you'll be wishing for a class B fire extinguisher. <img src="/forums/images/graemlins/zombie.gif" alt="" />