Reinstalled Grille Blocks ... Few Questions

[Miller88]

First cold morning yesterday. For some reason my Focus just doesn't make heat quick - the dealer claims everything is working correctly.

My 8 mile drive to work was cold until I got to the last half mile; then the car started making some heat.

I blocked off the lower grilles from the outside with b lack duct tape, then blocked off the INSIDE of the upper grille with the same duct tape.

Good news is - I had the same amount of heat within 3 miles this morning! I was at full heat and engine was at full temp by the time I got to work (according to digital temp gauge).

So I have a few questions.

If I blocked the upper grille from the inside ... does that have any affect on aerodynamics?

If the engine warms up quicker, I'm assuming that will cause a bit lower internal resistance (oil, trans fluid) and help mileage a bit.

Also, since the engine draws in it's air from the engine bay, did i effectively make a WAI? I'm assuming this will also help with mileage.

I can't wait for the first real cold snap to see how good the heat is!

[Daox]

Wow, that is really slow warm up. Even my Prius gets warmed up enough to blow warm air on my 7 mile mostly downhill commute in the morning.

Do you turn your heat on immediately when you get in the car? If so, this will increase warm up times. Turn the heater to cold and turn the fan off and you may see faster warm up times. Do you have a scangauge to monitor coolant temperature?

[ksa8907]

i need to put mine together soon. when it gets in the 20's, my car takes 3-5 miles at 60mph before the atf gets warm enough to allow converter lockup, full temp is at least another 4 miles, 10min total. if it gets near 0 the car will never reach operating temp on my 16 mile commute, 20min.

[christofoo]

Originally Posted by Daox

Wow, that is really slow warm up. Even my Prius gets warmed up enough to blow warm air on my 7 mile mostly downhill commute in the morning.

...

Does the 2nd gen Prius have a coolant thermos? If so I wouldn't compare its warmup time to anything.

Originally Posted by Miller88

...

My older Corolla has a considerably longer warmup than my Civic, ~6 mi vs ~3 mi.

I'm guessing the place to look is the thermostat - the valve that controls coolant flow to the radiator. Now you've got me thinking I should at least see if the Corolla has a thermostat.

It's hard to imagine the dealer wouldn't check the thermostat after you complained about slow warmup.

Regardless of underlying mechanical questions, grill blocking will help warmup times. WAI benefit is debatable since the ECU may retard timing to prevent knocking, but the probability of benefit is greatest in cold weather.

EDIT: I don't think anyone has a definitive test on the efficacy of grill blocking on the inside. I think it probably works reasonably well, as long as it's stiff enough and secure enough so the pressure can't push the edges back and cause air to leak past the block. Blocking on the outside is a somewhat safer bet.

[jtbo]

8 miles sounds bit long.

My diesel car takes that long to warm up to full temp when it is around 20F, but it does not take very long to have some warm coming out, maybe around half mile.

It was not always so, before I replaced thermostat car did not want to warm up to full temp even at summer.

New thermostat made world of difference, here it is common to block most air gaps from front during winter, without doing that air stream cools side of engine so much that car does not reach full temp, even with new thermostat.

With new thermostat and grille blocks I need to put heater to full warmth only below -30F, but of course at those temps it starts to take quite a while to get full operating temperature as diesel motor has lot of mass that takes time to warm up.

Not sure how thermostat is located in your car, but for some cars replacement is really simple job, some kind of repair manual for car would give good idea what kind of job it is, but for my car, I just needed to drain the coolant system, there was valve for that, open three bolts, take old one out, put new one in with new gasket that came with thermostat, refill and bleed the cooling system. Everything was easily accessible, perhaps only thing so in my car, took around 1 hour as I wanted to be very sure of bleeding being successful and I work very slow when temps below freezing.

[Diesel_Dave]

On my way into work this morning (~40 deg F outside), my truck took 16 miles to get up to full operating temp--and that's with the cab heater off, coolant and oil heaters plugged in all night, insulating blankets on the engine & grille completely blocked off.

What you have to remember is that the more efficient the engine is, the less heat that gets put into the coolant. I was thinking about that this morning...the amount of heat that goes into the coolant is a function of 1) the amount of fuel burned, and 2) the fraction of that fuel energy that goes into the coolant. So let's compare my truck engine to say a Geo Metro. If we both got 40 mpg, then we both burned the same quantity of fuel. Even if the engine efficiency was the same that would mean I put the same number of Btu's in my coolant and the Geo Metro did to his--except I have a whole lot more coolant and cast iron to absorb all that heat. So no wonder it takes so long to warm up. If I were getting 10 mpg I'm sure it would warm up faster because I'd be putting 4 times the amount of energy into the system.

I'm going to try to get at least a front belly pan on here shortly and hopefully that should help somewhat too.

[PaleMelanesian]

A couple days ago I reinstalled 3/4 of my lower block. The upper grille is always plexi-blocked. The day before, with no lower block, I parked at work with 182F water temp. With the block, in similar weather, I finished with 193F. How much that affects mpg is hard to say. Judging by my 30% lower winter mpgs, warmer MUST be better.

[Miller88]

From what I can tell the cooling system is working up to par. My experience has been, if the thermostat is not closing, the car will never come up to temperature or will have a hard time keeping it. The car, once up to temperature has no problem keepiing temperature

When I "teset" this, I just turn the heat on for a second, see what I get, then off to let the car continue building heat.

The odd thing is, this is a small aluminum engine with an electric fan that turns on *only* when needed. My Jeep, with a big cast-iron engine and mechanical fan that is ALWAYS spinning full bore ... warms up almost instantly. Never understood that one. Hmmm.

[Diesel_Dave]

Originally Posted by Miller88

The odd thing is, this is a small aluminum engine with an electric fan that turns on *only* when needed. My Jeep, with a big cast-iron engine and mechanical fan that is ALWAYS spinning full bore ... warms up almost instantly. Never understood that one. Hmmm.

The running the fan won't prevent the coolant from warming up because the fan only helps cool the coolant in the radiator--not the coolant in the engine. The coolant in the engine doesn't flow out to the radiator until the thermostat opens. Running the fan helps it warm up faster because it puts a load on the engine and t needs to burn more fuel.

[GRU]

put your hand on the radiator cap (don't open it) and feel if it's warm when the engine temp is roughly 1/4 way up...at that (1/4) temperature the thermostat should be closed and the cap should be cold, if it feels warm then your thermostat is open and allowing fluid to pass through the radiator so that's why it takes so long to warm up