Grill Blocking

[GasSavers_dan]

Repeated drives have since confirmed that outside air temperature has more of an affect on my fuel efficiency, than my grill blocking. I can only attain 25 mpg in the morning, never even close in the evening when the temperature is in the high 80's low 90's.

[GasSavers_SD26]

Originally Posted by dan

Repeated drives have since confirmed that outside air temperature has more of an affect on my fuel efficiency, than my grill blocking. I can only attain 25 mpg in the morning, never even close in the evening when the temperature is in the high 80's low 90's.

Is that more of a beginning of the engine coolant temperature issue? As in the engine is working more in the AM to warm up the block and coolant in 50 or 60 degree weather vs 80 to 90 degree temperatures later in the day?

Maybe try heating the coolant in the AM before leaving?

[ShadowWorks]

Let me understand this clearly, 202 is around 92 degrees Celsius, the temperature that most fan switches power up on, is this the optimum engine temperature?

What is the crystal scale that builds up in the water jack is not showing the true engine temperature and its actually hotter than the water would indicate?

[AltaGas]

Radiator Shutters

A bit of trivia - years ago my father tried to get truckers to adopt "shutters" for their semis. (Had a bit of a look like something between those new Ford shutter/venetian blind like grills and something you'd see on the side of an industrial building. )

They were very heavy aluminum and opened and closed via a automatic hydraulic heat control. Kept the engines at the ideal temperature in the Canadian winters - seems applicable today in light of the value of blocking the rad too.

I'm back - here's what I'm talking about... (I believe I even have a small one laying about - somewhere.)

http://www.borgwarner.com/products/t...ator-shutters/

I also see that Rolls Royce etc. once used them with vertical slats. I wonder if that would be very effective in terms of improved aerodynamics.

[GasSavers_dan]

I have since gone to 97% +/- grill blocking with intake air temperature usually in the 140's F (60- 65 C). That radiator shutter is great. Does anyone make them for cars or trucks yet? I don't have the skill to modify one of those commercial ones for my Dodge Ram.

[MarvHein]

I taped over about 2/3 of my GMC Yukon XL grille with transparent shipping tape yesterday and saw no ill effects on the dash coolant temp gauge. Outside temp was about 85. I'm sure I might have to back off when we hit 110 here in Vegas.

On closer inspection, I noticed a smaller cooler off to one side of the radiator. Oil cooler? Presumably some or all of this should remain exposed? I had also heard somewhere that the tranny cooler was integrated inside the radiator on these trucks... what effect might grille blocking have on the tranny?

Finally, what about A/C operation with a blocked grille? That's part of the radiator sandwich. As much as I'd like to avoid A/C use, I live in Vegas, where it's gonna run a lot of the year. (I do inhibit compressor drag as much as possible with my own thermostat in the cabin to combat A/C all the time tempered by hot water from the heater...) In my short test, I didn't notice any adverse A/C operation.

While I also didn't notice an immediate improvement in mileage due to the blocked grille, I didn't do any formal test runs and have faith that a gain will appear over time. Just don't want any unexpected pain while getting the gain.

Any thoughts appreciated.

[theholycow]

The smaller cooler is almost certainly the transmission cooler. The base model cooler might be integrated in the radiator such that you can't see it, but if you have the towing package it's almost definitely a separate unit. The easy way to be sure is to follow the lines from it and see where they go.

You can add the OEM transmission temperature gauge by buying a Denali gauge cluster and then just plug it in. It's totally plug and play.

I don't have faith that a grill block will help on the GM full size truck, but I will eventually try it. I think it will just cause the fan to run more. Your 2004 might have electric fans, which would be easy to make a DIY monitor light for.

[ShadowWorks]

This grille block business is new to me, I tried it by covering 80% of mt radiator and it increased my MPG from 16 to 20mph, what I didn't realise was my thermostat was jammed in the open position! never letting my car get warm so I was running on a cold engine condition all this time!, pig shiet!

I replaced it with a 82 degree thermostat but I am thinking maybe a 80 degree thermostat would be better?

How hot is the coolant in your cars?

[holypaulie]

Mine coolant goes up tp 216*F without any ill effects(80% grill block). I have noticed on my scangauge, that at this temp my ECU advanced timing a little bit wich is a good think. I can set on what temp to run my radiator fans with my aftermarket adjustable fan switch.

[GasSavers_ALS]

Here is some testing that MetroMPG did on grill blocking and it did improve the MPGs about 3% on the test car.

Part 1
metrompg grille-blocking-part-1.htm

Part 2
metrompg grille-blocking-part-2.htm