Air flow vs. rad shroud

[Hammerhead]

Ok stupid question time from the village idiot...
Which is better, open to allow the air to fully flow through the radiator allowing it to do its job, or if you watch my Rad Shroud video.
As you can see because of the large size of my rad, and the normal size of the fan, a full 1/3 or more of the rad is blocked by the very "flat" portion of the shroud, therefore not really allowing for good cooling air flow.
Yes, I know that when the fan is engaged it causes a massive suction and will draw the air through it, but man that shroud is such a massive restriction.
The fan will still draw a significant volume of air simply due the size of the fan, and since I am MM2vU'd it doesn't need to engage during regens n stuff, and I'm also APU equiped, so I don't idle much.
I am strongly considering pulling the flat portion of the shroud to see if there are any gains.
I know airflow is very significant in cooling, because back in the cabover days, the guys with them that pulled heavy weights never ran nearly as hot as the conventions due to the cab tunnel allowing the heated air to escape easily.

Has anyone tried this?
Pros?
Cons?
Do it, don't do it?
And most importantly, tell me WHY your opinion is such...

I really feel like I'm giving up almost half my rads capability. This summer has been exceptionally warm, and I'm always trying to increase heat dissipation because of my job.

[Volvo8873]

I literally just tore the one off my beater Volvo because it was busted up. Too early to tell as today was the first day. I do know that I dropped 150 degrees in EGT temps but I also cut away my inner fenders too at the same time which IMO is probably more beneficial than anything on a Volvo.

I do know on certain hills that I pulled today the truck coolant temp would always rise but today it did not and with the load today I easily hit 7 mpg today but with power only its hard to tell.

[Nilao]

I shy away from removing shrouds. At highway speeds it helps but at low speeds is where it shines. Without it the fan will draw hot air from the engine compartment instead of through the radiator causing the engine to overheat. The shroud is there to keep that from happening.

[Chamberpains]

Im with Nilao on that. The purpose of all the shrouds and hanging plastic rubber and all the directional junk that rattles off and get snagged on everything when your opening and closing the hood, is to funnel air across and over the engine. On trucks with very tight engine bays its very important to keep all that stuff maintained so you dont obstruct or redirect air flow from going over the engine and transmission. Now trucks with larger engine bays run in to a little different problem if you mess with to much you can get hot air swirling under the hood and not efficiently flowing thru the engine bay. Leaving an insulating hot air bubble around the engine
You may very well create or compound a small problem.

I personally would just let the fan do its job. If anything, look to see if your truck has an upgraded fan and maybe a different shroud (yours does look awfully constricted for such a big radiator but looks and true functionality are often 2 different things). I found on my truck that the new fan I bought was lighter, smaller and pulls A LOT more air when engaged. And yes its OEM. I replaced it just because after 12 years I figured plastic fatigue was bound to have it come apart and I wasnt chancing a radiator for a $180 fan. It was a nice surprise that International had upgraded the design of the replacement fan.

[snailexpress]

You can remove this shroud but be ready to install it back before you hit first uphill loaded.:big_smile2:

[Volvo8873]

I only tore out the shroud as it was becoming a problem for the fan and I also need to install a new radiator in the next few weeks when I get a little time. Leaking is not the problem for this one but the corrosion from 13 years of rust belt abuse have taken its toll. Surprised it has not leaked yet to be honest... but I am sure it will when I am up in International Falls, MN at 5am in the morning and it is -35 below zero!

I am just trying this out for now. I will post a few pics tomorrow, it is kind of funny as it looks like an old Cummins 855 with the fan exposed. If it does make for a problem then the new radiator will be installed with a new shroud.

[Hammerhead]

Yes, the overheating while pulling at low speed is my obvious concern.

The radiator size was the reason that I ordered this particular model of truck, but when it's over 95ish it just seems to have the opposite effect of what it should. Until 90 it's great, but once it gets much over that it doesn't seem right to me.

My new gig has me running more TX than Midwest as before, so that's why I'm looking for some form of accrued heat relief.
I'm even considering cutting two holes in each side of the hood and installing electric rad fans to help expell the heat. With my frame being full of tire chain hangers, boxes, and the APU, the hot air must travel all the way out past the diff's to escape and I'm truly feeling it this summer. I'm at double the number of >100° days I normally have...
I'm a fat Canadian, I ain't built for this crap!

[Hammerhead]

Alright, FINE!!!
The village idiot has relented from his hair brained scheme of pulling the flat portion of my shroud.:too_sad:

   
This ^^^ may have been a contributing factor:huh:
Jeesh, I can't keep CAC's in this damn truck! I've had this truck since new, 12/09. The first CAC lasted 3 years, and since then it's been every 2 goddam years! Almost like clockwork.

===

I also replaced my thermostat and seal, it was not scraping metal on metal like the last one I changed was, but I had it open to inspect and I had new parts, so in they went.

===

Due to my, IMHO piss poor shroud design, and my belief that the full dimensions of the rad are not being utilized, I also put one of these in...
   
I am thinking/hoping that the 2-speed hub will help draw airflow through the "stagnent flow" portion of the rad...

I know, I know. You never make more than one change at a time or you don't truly know which change caused which or how much of the result.
Crap was apart to change the retardly large CAC in this truck, and that made access to these other items easier. Yes, that means I'm a fat lazy bastard, and I'm ok with that. It leaves more time to drink beer and post my results here, so too bad!

[Rawze]

(08-25-2018 )Hammerhead Wrote:  ...

Jeesh, I can't keep CAC's in this damn truck! I've had this truck since new, 12/09. The first CAC lasted 3 years, and since then it's been every 2 goddam years! Almost like clockwork.
...

make sure all your bushings are good and that things are not over tightened. That whole front structure needs to have a bit of give to it. Also when installing new, don't force any screws into their holes if they do not align up perfectly. Grind out the hole in the frame instead so that no stress is applied to the CAC or radiator.

Lastly, when opening your hood, don't let it slam open. This will kill a CAC in a hurry and I see lots of guys do this at the truck stops while shaking my head every time.

You also haul heavy. There is likely some twist in the frame when pushing things hard so make sure your lower front structure bushings are in good shape/not bound as well.