Having driven my HHR in the winter last year, I got spoiled by the almost instant heat. Actually, my old beater, a 97 Probe, had very quick heat as well. Both engines are aluminum and the temp gauge would be climbing after just a few blocks.

My new beater, a 98 Z24 Cavalier has an iron block Quad 4 that takes muuuuuch longer to come up to heat. It's going to be a long Winter.

 

put a piece of cardboard in front of the grille - beaters only

 

Block Heater. My Jeep has one. I love it!

I agree with you about how quickly the HHR heats up. Very nice!
But I don't drive the SS unless there is no chance of accumulation.
Jim

 

With the onset of the colder weather now I'm reminded now of how slowly my HHR heats up.There's no malfuction,it's the aluminum block.Aluminum engines don't build or retain heat like an iron block.So my car is warm but not hot by the time I arrive at work,5 miles and about 10 minutes from my house.On longer trips it gets nice and toasty.
BTW,I did order a block heater with my car.But the owners manual says it won't even work unless the air temp is well below zero.(Fahrenheit).Maybe I'll try it anyway.

 

Block material has noting to do with heat up time.

Most new cars will heat up fast to improve emissions at start up. The Emission are at their worst at start up. Some company do many different things to get the new cars up to temp fast and the converters up to temp fast.

On the Cavalier the age of the car and the type of emssions system has more to do with the longer warm up. My 04 GTP is still like the older cars and take a longet time to heat up.

 

Aluminum has a thermal conductivity 4 to 6 times that of iron. Moreover, the thermal mass of an iron engine is significantly higher, giving it a double whammy. It absorbs heat like a sponge where aluminum will transfer heat to the coolant much sooner. As a brief test, take an iron and aluminum skillet, put them each on a burner, and see how long you can hold your hand on each one.
The emission systems on the Cavalier are virtually identical to the HHR, except for EGR, which does not engage below full operating temperature. Your GTP is also an iron block. Until the thermostat opens, heating of the block is determined by the energy input, which is dominated by displacement, and the thermal mass and conductivity of the block. Thermostats haven't changed in 75 years. The differences in newer emissions systems are in better techniques to avoid idle enrichment, such as cam phasing, to reduce emissions during warmup, but they can't materally affect how long it takes all that stuff to heat up.
In my GTO, I replaced the aluminum LS1 with an iron LQ9, with other systems such as programming, thermostat, emissions, being identical. Warmup takes noticeably longer with the iron engine.

 

It does not matter the block material as the cooling systems are designed to get engines up to temp and keep them at temp. THese things are designed as a package and take the block material into consideration with the whole package. So just buying a car with a aluminum block will not effect warm up as the system has that covered.

The conductivitiy of the block material is not relevent.

You're material knowledges is accurate but you fail take in the other factors of the entire system such as radiator size, radiator material, coolant capacity, Thermostat temp and size, hose sizes, coolant flow speed due to the pump and many other factors that contribute to the efficiency of the cooling system.

All these things involved in the cooling system contriubute to the speed and contol of the engine temp. Just one of these things fail and the temp can go higher or lower real quick no matter what the block is made of.

The MFG take the block material into consideration when they build and design these system. The system as a whole is what really controls the cooling or in this case warm up.

The bottom line is todays cars are designed to get the engine up to tempo and stay at temp for start up to cut emissions.

You might note the VW air cooled engine is no longer being built due to the uncontroled emission.

Even the air coole Porsche 911 is no longer built. Porshce and Subaru still build a similar engine as the flat VW air cooled but today they are water cooled to control their tem and improve their emissions that will pass federal standards.

The bottom line is a water cooled engine temperature is controled and regulated by the cooling system not anything the engine is made of.

I do agree with you that other computrer factors can influance engine temp too anymore. It is different depending on the engine and style of engine it is.

The ideal thing for a car is to get it to operating temp asap and keep it there to keep it efficent.

If you will note even the computer will send a code for a failed theromstat anymore, Why? Emissions.

 

Denying that thermal conductivity has anything to do with transient heat transfer is like denying that gravity has anything to do with you sticking to the ground.

Before the cooling system can do absolutely anything at all, the heat generated in the combustion chamber must propagate (spread) to the water jackets. What does it have to propagate through to get there? The engine block. As mistermike said, the thermal conductivity and specific heat capacity of the block material are going to play a significant part in the time it takes for the engine to heat up. Again, this occurs before any heat reaches any of the water jackets, cooling lines, radiator, thermostat, whatever.

 

I do not deny thermal conductivity that is what blocks and heads of all materials do.

I just state todays cooling systems and related systems are designed by the MFG to get the engine to temp as soon as possible. No matter if it is Aluminum or Iron they both are controled and regulated for a fast warm up.

The faster a engine is up to temp it is more efficent in MPG and emissions. It also reduces wear. Todays engine are set to warm faster and run hotter than ever due to these reasons.

There is no denying the thermal conductivity but the fact is no matter the material it alone does not control the speed or the temp of engine warm up alone. Neither of us are wrong here as all of this works together.

The aluminum is conductivity is only a side effect alumiunum. The fact remains they use aluminum only for the lighter weight no because it conducts more heat.