Grill block over heat - Fuel Economy, Hypermiling, EcoModding News and Forum

wildfire8 · 03-12-2009, 04:20 PM

I was testing a grill / bumper block using painters tape. I taped my whole front up covering all the holes. I left a small square hole for some air to still cool the radiator. Was driving on the free way and the temps started jumping up and down. My needle usually sits just under half temp and it was jumping up to almost max temp. On my scan gauge with out the block temps are around 183F+/-. With the block the max temp hit 213F. I want to keep an block on there but I am worried about my engine getting damaged to over heating. What is a safe temp range to look for with a block on and not hurting the engine?

vinny1989 · 03-12-2009, 06:00 PM

Ive always been told - in general don't let the temperature go over 3/4 for too long.

YMMV

aerohead · 03-12-2009, 06:26 PM

I'm not comfortable allowing the engine to run at any temp over normal.I would progressively increase the size of the opening until "normal" temp is restored even if that requires eliminating the block altogether.

cfg83 · 03-12-2009, 06:40 PM

wildfire8 -

I agree with aerohead. I do allow about 10 degrees above normal, but over 10 degrees and I am watching it like a hawk. I installed a manual fan radiator switch, so I can "control" the temps without removing my grill block.

CarloSW2

MetroMPG · 03-12-2009, 09:06 PM

wildfire8: the temps were probably "jumping" up and down because your cooling fan was cycling to keep the engine from overheating.

You want to avoid that heat stress and the added electrical load from the fan.

So you need to size your block so the fan doesn't come on in normal use, or simply size it so the temp never goes over your normal operating temp. The ScanGauge is useful that way, since it records max temp experienced during the current trip.

1337 · 03-12-2009, 09:18 PM

What's "too high" of a temperature? Without a grill block, my mazda hangs out at about 205 degrees on the highway in warm weather (70-80 degrees), but with the block in 20-30 degree weather, it barely hits 180 degrees. I think I'd have to hit 280 degrees for the temp gauge to get close to the "danger zone."

almightybmw · 03-13-2009, 05:09 AM

205 is a good temp. my truck runs at 205-210 on the highway or in town (blasted mechanical fan). My GP is much much lower, around 175 or so. No idea why. I guess the aluminum block doesn't get hot much...? Totally weird since the 'stat is 185, or should be.... I have run the GP at 210 before, and not worried. It's the high end for the heat, but no where near the 250 red zone.

here's a nifty thought: Find an auto Protege at the junkers. Take it's fan. It's a two speed instead of one speed. Seriously. It'll get you a low speed help with the heavy up and down temp cycles. If you can get it to hold steady around 200 you're doing great.

NeilBlanchard · 03-13-2009, 08:15 AM

Hi,

Can you please post some pictures? Where is the one opening? Is it down low under the front bumper? The location of the opening is as important as the size of the opening.

I went from this:

to this, and so far I've had plenty good cooling:

wildfire8 · 03-17-2009, 07:22 PM

Sorry been busy.
I just did a tape mock up of a block on my bumper and grill. I had left an opening in front on the bumper. It was not that big.

I am now making a bumper block out of plexie glass. I got from lows from there scrap pile they where going to throw out. They happen to be the perfect size just needed to shape the edges for my bumper. And cut a hole for the fog light.
I am still working on it.

1st picture is of the stock car.
2nd picture is of the taped version of the block. I never took a picture so I just made a mock up drawing of what I had. The red is where the tape was. The part not taped on the right of the bumper is where my ram air tube is for my Intake. The other side was was covered all the way.
3rd picture everything that is in red on the 2nd is going to be be block with plexie glass but the hole is going to be bigger the red box is going to be the size of the hole.

I am going to just try it out with just the bumper for the first little bit. Then work on the grill.

jamesqf · 03-17-2009, 08:59 PM

If you have a ScanGauge, you probably should ignore the car's temperature gauge, as they're notoriously inaccurate. Mine jumps to its "normal" reading at about 140 F on the ScanGauge, and doesn't budge when temps climb to 210 F.

I would try keeping temps in the 195-205 F range. Note that you should size the grill opening for hot weather, or make it adjustable. The standard opening is probably sized to allow adequate airflow when climbing mountains in hot weather.