So I'm pretty much convinced that my truck either has a very low temp tstat or no tstat at all, it never gets hot. I added an UltraGauge and it has yet to get above 140F. Since it's still winter here it's pretty annoying to not have much heat, especially in the AM. I've little doubt the cooling system has never been touched (well except for the tstat thing) and it only has 126k on it, time to be preventative and regain some comfort! It occurred to me today too that since the truck always is running at low temp it's probably not running very efficiently and thus my fuel mileage is probably down. May also be a contributor to what seems to be a bad cat...makes sense if it's always running a bit rich.

So that being said, time to do this. My plans are these:

1. Aluminum rad (will look into having the stock rad rodded and redone for sale afterword)
2. ditch stock viscous horrid sounding high engine load water pump shaft loading fan in favor of large efficient electric puller unit - will add a manual switch as well as tstat controlled (not stock tstat, add on type)
3. new 180F tstat
4. new coolant reservoir cap (what the heck)
5. new uppper and lower rad hoses...others, not sure yet, need to check
6. new brass impeller water pump
7. Would like to do new ECU and gauge temp sensors...need to find P/N's to check for cross over parts

Of course I'll change the coolant as well, may flush depending on how the stuff coming out looks. Anything else I should consider?

Cheers.

 

For where you live, get a hotter t-stat, I run a 195, truck never gets hotter than 205, and thats in the summer with the a/c on driving trails for hours on end.
Forget the electric fans, buy the Chevy fan clutch from AutoZone, $50 lifetime warranty.
AtlanticBritish sells a cooling system hose kit, thats what I did, its worth the money, exact fit, high quality.
AtlanticBritish has all the sensors you want, as well as part numbers for those sensors.
For the temp sensors you can just remove the, clean up any corrosion with a emery cloth and put them back, they are just cooper.
As long as both of your a/c fans behind the grill are working you can remove the clutch fan for the winter, thats what I do.
If you are not already get on AtlanticBritsh's snail mail list, as well as Rovers North.

 

Seems like for testing in the garage you could block rad with cardboard and push temps to 200+, just to see if stat will operate. Or pop it in a pan of hot water to test when it you swap it, in case there is something else making all chilly stuff. There is another orifice on the D1 manifold that may be of help, it is the "bolt" fitting below the stat hole, was part of the heater circuit in earlier V-8s.

Gauge stat is sensor to left, OBDII via ECU reads ECT on the right (square plastic 2 wire top). So you can leave ECT for the ECU, and put in what ever you like for the gauge.

Would think if stat is blocked open, and you crank truck cold, water will flow past stat to top of radiator. Messy to check.

 

I'm going to mount a spare set of fans from my Probe GT. 14" and 12" pullers fully shrouded. Exact same width as the rover radiator and only an inch and a half shorter. Should fit really well and since they are just laying around i figured why not. I think the FAL dual 12" fit pretty nice too

 

When do you put your fan clutch back on?

 

Here's some rubs with the D1 and electric only fans. I have a "feet per minute" air flow meter, and my D1 was making like 800 feet a minute air flow at idle, switch on the electric fans (AC condenser) and that bumps up to say 1100 feet per minute. Note that this is air speed, not cubic feet per minute.

So fan(s) would have to be 3 times as "strong" as the elecric condenser fans in the D1 to approximate the air flow at 0.0 miles per hour. Now let us take the D1 up to 10 miles an hour in traffic, or rock climbing, etc. The higher rpm boosts the air flow with a clutch fan. The electric fan remains at a static pace. Of course, when you get to 60 mph, the air flow from forward motion is 5280 feet per minute. Don't even need the rad clutch or electric fan. Might save some gas, but guys in the north who have driven in the winter with no fan don't report wild increase in mpg.

Another thing is amps. I used a clamp on amp meter, and measured my D1. With everything that came on the truck (stock lights, wiper, radio, AC with fan on high) running, it draws 85 amps. From a 100 amp alternator. So don't plan on electric fan and eight new Hellas. And the extra amp load does increase the load on the engine, so you don't get to keep all of the HP "released" by using all electic fans.

Yes, you can find electric fans to do the job. You'll want the biggest flow you can poke in there and live with amps wise. Electric fans do work on vehicles. There may be some from the boneyard that will fit, and may improve the breed. If it was easy to do this and save 10 hp, boost mpg 3 miles per gallon, etc., a lot of people would jump on it.

 

I'm not concerned at all about switching to an electric fan...and I won't shroud it either, not necessary. I doubt a D1 motor, even fully loaded, runs as hot as the engines in the various race cars I've owned. I will be adding a larger puller fan to the back of the rad and it will be controlled by its own tstat (but I will add a manual switch as well). I'm more interested in getting the load off the water pump shaft, losing that horrid jet engine sound every time I hit the throttle, and some mild improvement in efficiency. I certainly don't expect to set the world on fire with fuel mileage improvement - if I get a consistent 1-1.5 I'll be ecstatic - but all the little benefits make it completely worth it. Oh, and the electric fan is essentially lifetime vs the clutch which will need to be replaced...regardless of how cheap/easy they are to find. A decent electric fan is cheap too, don't need anything fancy. This will add a fair bit of room in front of the engine as well.

I do plan to clean out all the years of collected birds nests in front as well.

 

Probably but that's not going to solve anything and since I have not history of maintenance showing this stuff has been serviced I'd rather just deal with it preventively. I will check that bolt in front though.


Cheers.

 

The venturi shroud does improve what the fan can do. I tried running with a slightly larger fan and no shroud, on the stock clutch, and results were not as good as with trimmed fan and shroud. If electric fan is large enough to start with, it may not need a shroud, but the shroud will almost always be a plus.

Being able to switch fan off during wading would be a plus.

Keep in mind that there are aluminum after market D1 radiators now for about $235, several have been posted about. But I had my copper and brass oem roddend out and flushed for $75.

Of course, everyone should take in a Summitt Racing store if they pass by one, wall to wall goodies.

 

True, the shroud would provide improved efficiency in the fan during low speed use (IE stop/go traffic, traffic jams) but a high speed electric fan should provide plenty of flow. During normal highway cruising when the fan isn't needed (and is non-op) wind flow thru the rad will be betterer.

I am picking up one of the ebay alu jobs, I think that will do the trick nicely. I do plan to get my stock rad cleaned/rodded and then I plan to sell it to help cover the costs of the new stuff.

Cheers.