Bumper holes

[Shikaroka]

So, what are the two holes in the front bumper for?
Extra air? They don't seem to lead anywhere. Are they only on the diesels?
I have seen a couple guys mount the heat sink for their PMD there.
Would it do any harm to mount some driving lights in there?

[DennisG01]

Yes, only on the diesels. Yes, for extra cooling - directing it over the radiator. Try the lights and see - if it's causing your temps to go up, just move the lights to below the bumper - there's already holes along the bottom edge of the bumper you can use to mount the lights.

[DA BIG ONE]

There are supposed to be air ducts in them there holes directing air towards rad & coolers.

[a5150nut]

If you mount lights below the bumper watch you raproach angel. They tend to dissapear below the bumper...............

[Shikaroka]

There are some plastic "shields" in there, that assume are there to protect the oil lines and maybe direct air up. I can't imagine they help much.

I was just wondering if anyone had mounted any lights there.

[DmaxMaverick]

They are necessary. If you block them too much, summertime loaded use will cause ECT issues. Small "bullet type" lights may not effect the airflow enough to cause problems, but the 6.5 needs all the cooling help it can get.

If you have doubts, tape them off, hook up and go hit a hill during summer. You won't get that tape off quick enough.

Removable fog lights would be a good idea. When you need them, cooling won't be an issue. Who needs fog lights when it's 105

[DennisG01]

If you mount lights below the bumper watch you raproach angel. They tend to dissapear below the bumper...............

I'll second that one! I learned the hard way. I've been pretty good at remembering over the last year, though.

[Shikaroka]

I keep hearing about these trucks overheating, but I have never even seen mine get up to 200 degrees yet.
I haven't towed much, but I did tow a small car last night and it never even got above 180. It was kind of cold last night, but I towed it about 40 miles on some hilly terrain.

[DennisG01]

If your cooling system is clean (including radiator fins) and you're not towing too much weight, you will probably never have any problems. Mount the lights and see what happens. In your situation, I highly doubt you're going to notice any difference at all. Besides, if it does start to get hot, just relocate the lights.

[DA BIG ONE]

Only time GM installed lights in those holes was on the Tahoe Limited which had a gas HO small block. Cooling load is nothing on a small block when compared to the turbo diesel.

"Don't block them holes".

Check out Hella they have small and powerful lights that can go on top or bottom of bumper..........

[Shikaroka]

Yeh, thanks guys!
I probably won't risk it.

[bluuzman]

just a comment.....Running an engine too hot must be avoided but instead of just cooling, maybe we should think about "temp management" :). These vehicles are operated in quite variable environments.

Many diesel drivers block any bumper holes / grille as well. It's well below the freezing point down to -35F up here, no cooling issues, but slow warming up and not enough heat for passengers ;)

In my opinion it's better to keep the engine close to normal running temperature rather than let it run too cool all the time unless you want to have extremely low mpgs and a shortened engine lifetime. That's why new diesel cars are almost all equipped with extra heaters here cause they do not hold normal operating temp in real winter weather.

Of course, before these cold days are gone, you need to remove the blocking to let air flow freely and allow max cooling.


-a