Junk yard. 2000 Blazer. Their clutch also screws onto our water pump. $19 near me. As far as fit, you'll have to look at that. On the D1 it fit, but blades had to be precisely trimmed. Using it without the shroud makes quite a loss of performance.

But first step on a D2 is replace factory stat with either the soft spring on that opens sooner, and is fully open at 180F (vs fully open at 204F stock), or the in-line stat.

I would agree that hood vent might make a difference, but based on my tinkering this morning, I did not see any change at roadway speed (already at low end of thermostat "starts to open" temp), only at idle. And having the whole hood open is a big area, not sure just several 4 inch diameter holes would make enough difference at idle.

I'm thinking maybe try the single big electric fan out of a Taurus as a replacement for the AC fans. I'd have to do more tinkering. But even with my temps, I'm ahead of these guys that have 218-221F. I like hog meat slow roasted over hickory coals, not engines.

I agree with DM on the design for a 4 cylinder. But I believe the heat up at idle is more due to change of air flow speed over the radiator coils from highway 5280 feet per minute to less than 20% of that at idle.

 

OK, Monday AM, decided to re-test, this time by removing the rubber strips on a D1 that connect rad to the AC condenser. Great place for leaves to collect.

With strips out at 8:25Am crank it up, AC turned on

8:34 IAT 129 ECT 180
8:40 IAT 133 ECT 180
8:56 IAT 163 ECT 199

On the road at 60 mph

9:08 IAT 124 ECT 178
9:13 IAT 124 ECT 178
9:18 IAT 118 ECT 178 - 180

At idle with AC on after road test

9:19 IAT 124 ECT 183
9:58 IAT 196 ECT 221 (new Depends)

AC off, idle

10:06 IAT 194 ECT 219

Hood open, AC off, idle

10:20 IAT 151 ECT 194

Hood open, NO ac compressor connected, ac fans forced on

10:26 IAT 142 ECT 183

Hood closed

10:27 IAT 142 ECT 183
10:38 IAT 158 ECT 185-187 (IMHO this proves a little extra airflow would help)

Strips back in, AC compressor on

10:53 IAT 174 ECT 205
11:12 IAT 189 ECT 216

Conclusions:

For all of this, the factory temp gauge did not budge and remained below the 50% mark. Worthless as ***** on a bull.

Running down the road with rubber strips between rad and condenser pulled out might gain 1 - 2 F improvement, and considering I am not making this run inside a controlled environment, that could 1 or less improvement. Certainly not 10 F or anything close.

Idling with rubber strips out is no magic bullet either. Yesterday with them in climbed to 196F in 20 minutes at idle. Today, at 39 minutes of idle climbed to 221F, strips out.

Viscous clutch feels firm (not free wheeling) when hot.

At this point, IMHO, the idle speed air flow is lower than it should be, there is enough airflow at 60 mph that increased engine heat is correctly disposed of by radiator, thermostat keeps temps at low end of range (178 - 180, depending on strips out/in). Even with AC on. Now at idle, will have to work on ideas to increase the air flow. Those might include:

Saudi grille - can repeat test with grille off before building Saudi style grille
Different electric fan(s) (maybe 2 D2 fans)
Bigger radiator (from what?)?
HD clutch


Or forgetaboutit - as how often do I idle for long periods? I could also have start of HG issues for all I know.

 

Why are you guys so concerned about under hood and engine temps?
Do you guys really believe that a few degrees is going to make a difference in the overall life of your truck?
I just find it very hard to believe that you will be doing any actual good.
If you want to do it just because fine, I understand but if you actually think it helps I do not understand.
Can someone help me to understand?
I think that Rover would have done it if it needed to be done.

 

Yes it does not help anything, if you run sub 200 consider yourself cool, any less your just wasting time money energy and risk running too cool

 

I think a hood scoop will indeed look awesome Spike and i wanted to have the option with the flap to be able to dump a little cool air on the motor during ten hour drives. Like i said earlier i am not sure if there will be much benefit from this but it may drop my temps may not but i like the scoop!

 

If y like the look of the scoop cool, I think it'll be mutated.

And your engine should get not hotter in 10 hours than it would in 1 or 2

 

It would have to be a BIG scoop, close to the size of the fan shroud opening, to make significant change at idle. It won't make any difference at high way speed unless you have other problems.

 

You like the looks/idea of the hood scoop thats all good
.
Once the engine warms up it does not get any hotter after 24hours of driving than it does after 1 hour of driving.
Thats what the cooling system does, it cools the engine.

 

Yea I'll be alright if it don't cool any more i have 0 overheating problems so its no concern i just like the look! And wanted to share what i was doing!

 

All this talk made me think of these: Pacet Automotive Cooling Fans - Bonnet Fans