1st complete grill block tank emptied
 

I'm happy!!
Even in the worst possible wheater conditions my fuel consumption decreased a little bit (1,5%).
I know one fill up is to early to make any conclusions, but this looks good.
Have a look at my gasslog for details.

I would wonder why it takes 30 minutes of driving, even in freezing weather, and especially with a grille block, for the engine temp to reach 85C. My '83 Cad (which has a feature on its computer to get diagnostic info, such as coolant temperature) will reach that in about 5 miles of driving, or maybe 10 minutes of sitting in the driveway.

I haven't used a grille block on the Cad because, living in the desert, the idea of blocking air flow to the radiator just seems wrong.

JoeBob, I think it's because :
- the way I drive. I don't waste much energy
- the very efficient engine (the more efficient an engine, the slower it warms up)
- freezing weather: the cab heater takes the heat from 50?C on (than the fan comes on for the cab).
In warmer conditions (18?C ambient) and some sunshine I reach 85?C much quicker (less than 10 minutes) => no cab heater on.
Without grill block, I didn't even reach 85?C after 30 minutes.

I've blocked my radiator 90-95% with some cardboard between my radiator and AC condenser. I have some slits cut in it so the cooling fan will do something when it kicks on.
For the most part i wouldn't know it was there. The water temp doesn't get out of it's normal range, except when i'm driving up hill for 1.5+ miles or when I drive over 65mph (not often for me). But in these cases all i have to do is blast the heat to bring it back down.

I don't have any scanning equipment yet, and i can't say i've notices any FE improvements. I do like the quicker warm up time, which must save some fuel.

Dr. Jerryrigger, you should put notes in your gaslog so that it's easier to remember when you did things like that, and also so it's easier for other people to see how it affected your fuel economy.

That is true. I should also enter gas logs more often, so i remember those things. I think i'll add that note in to approximately when i did that.

Have you tried toughing it out without the cab heater, at least at the beginning of the trip? Speeding up the warm up time should improve economy. It may even heat up the cabin quicker. That may be a matter of perception, but I prefer waiting for a blast of heat instead of getting a trickle from the start.

I didn't because my car does it 'automaticaly' for me. If I don't set my heating on a safety related position (defrost for windows) AND it is set on automatic, than the system will wait to blow warm air until engine coolant temp is 50?C. And that is according to me hot enough to let the engine run rather economical. The moment the cabfan comes on it's right away pretty warm.
I also checked the heatercircuit: there's no valve in it that stops the coolant from circulating to the cabheater if you don't need heat. So there's a loss anyhow the first minutes, even if you don't need or ask heat.
To be honest: for safety reasons I don't want to drive uncomfortable (cold, with a thick jacket). I like it to be in a sweatshirt maximum. Makes me feel much better behind the wheel.

I agree. Comfort is of the utmost importance to me. I can drive safely when uncomfortable, for a short time, but as I get tired of discomfort my driving can suffer. Efficiency suffers much more quickly; if I'm uncomfortable, I get impatient.

I've never been a fan of automatic climate controls in cars. I'm usually happy, weather permitting, with just ambient airflow through the vents. Most auto systems I've come across don't let me do this without risking heating the air, or turning on the compressor to cool it. It's great that your system waits for warm up.

Systems without a valve to control coolant flow to the heater core instead control air flow over it. Don't call for heat and there is no airflow. There is still loss over a coolant control system, but it isn't drastic.

I agree comfort is important. Perhaps I am more temperature tolerant than most, but I'm usually fine going a mile or two without heat. Past week I have also been taking advantage of the remote start while walking up to the car.