I want good mileage and I think my car choice proves that. Apparently raising the engine compartment temperature while not overheating, of course, raises MPGs as well. What about long term engine reliablity? What brings this question up is a thread over at cleanmpg.

Grill Block on a Honda Fit - CleanMPG Forums

I plan on driving my Fit for a long time. I doubt I'd do such a mod but the thread raises interesting questions. When I raise the hood on my recently turned off Honda I was always dismayed at how hot it was. I'm looking for MPGs but not JUST MPGs! any thoughts? by the way there are lots of interesting posts regarding the fit over there.

 

You'll go through oil quicker. Maybe try a hot air intake first? Increasing the under hood temps puts a lot of unneeded stress on hoses, belts, wire insulation, header welds, etc.

 

as hinted at in that link.... sensors on the engine are designed to compensate for all variations. so, in "normal" ambient driving 60-90degF, there will be ZERO change in fuel consumption. you may reduce drag slightly, but i bet not much.

however.... grill blocks are EXTREMELY effective in the winter months when ambient temps are freezing/sub-freezing. most of the time during those months, the engine doesn't even get to full temp and the heater core is acting as the radiator.

 

The car will get at full temperature even if it's -40°c outside but it's gonna take a lot more time and even more time with the heater on... that's why thermostats are there pal!!

Personally, in winter months, i give my car about 1 to 2 minutes warmups and i'm gentle on the gaz pedal!!

Marko!!

 

Yea, you can blow a head gasket if you get right on the gas with not warming up the engine for a lil in those cold months.

 

what? that's the dumbest post i have ever read. you're not going to blow the headgasket. as long as you're not trying to be an f1 driver while it's warming there's no issue whatsoever. that 1-2mins idle is a complete waste of gas. only benefit is for driver comfort. i've driven hondas thru dozens of winters, never warmed them up and i've never had a headgasket blow.