Can I add a pusher fan to stock set-up?

[ubtripn]

A while back I got advice on the board about how to keep my engine cool this summer. I went with a standard shroud with a mechanical fan. Tried different thermostats, runs fine except when it gets above 95 degrees. It will be over 100 out next week. Right now this is all I drive (kids have the other cars). Would adding pusher fan to the front of the new four row radiator work for when it get's too hot or would it just block air flow?

I would like to just have it on a switch and turn it on when I want for now, would this work?

[ubtripn]

Disregard, I am just going to do the Jeep Grand Cherokee electric fan since it will mount inside my existing shroud. I will pick up an easy wiring kit. Hope I get this right.

[Andy4639]

It will work but if you have the Chevy truck clutch fan and the shroud it should do fine also. Make sure the air is coming through the shourd and not around it.

[special-K]

Why not just fix what's wrong with your truck? Maybe your radiator is restricted. It got just as hot when these trucks were made as it does now and they did the job and did it right. I've towed and hauled a big camper with stock equipment in all conditions w/o issues.Took my camper truck from here in Maryland to Taos, Chama, Pagosa Springs, over Wolf Creek Pass, Cortez, Mesa Verde, 4-corners, Page,North Rim, Sedona, Crater Nat. Park, Petrified Forest, and straight back I-40, up through TN, KY, WVA, and home. Went over mountains and through desert with no issues. Why complicate things and add another thing to break? If the radiator isn't flowing right in time it will be a bigger issue that the fan won't help

[ubtripn]

Thankless, new 4 row radiator, new fan and clutch, new long nose/high flow water pump don't know what else too look at. Fully sealed for air flow, can't figure it out.

Think I will do the electric fan in the existining shroud with the Grand Cherokee electric fan mod.

[prodjay10]

If your timing is too advanced, it'll cause more heat. That's what a mechanic is telling me about mine.

[ubtripn]

That is definitely a possibility. Thanks. I cannot find the right timing, its kind of a mystery crate engine I bought without the spec sheet for 1000. I have it advanced pretty far but running good.

[ubtripn]

I meant to say thank you - not thank less =)

[ubtripn]

The only issue I can think of is I got the ac shroud which is deeper and as a result the fan is 1/2 from the rad but DEEP into the shroud. (I want ac one day) I could try different spacers.

[ubtripn]

The air is blowing hard out of the shroud hole towards the engine though.

[Andy4639]

I would have the timing checked by a good mechanic and it should be fine if all is as you stated.
These trucks where sold new just like they are today and they never over heated with the right parts and know how!

[RichardJ]

I do understand what you guys are saying about not needing a pusher fan if everything is right with the engine to start with.

My poor old 292 came from the factory with a fixed 4-blade fan and no shroud. I wanted to keep it simple when I added the AC, so a '94 Cad pusher fan runs all the time with the AC. It has extra finger protection so it works perfectly behind the hood release.
The other fan came off an '89 Cad and is connected to 208* thermo switch on the thermostat housing and to my knowledge has never turned on.

I didn't want to give up the reliability of the fixed fan and this turned out to be fairly easy to install. Still no shrouds. When you have to start getting anal about the shrouds, you've got other problems.

Triple-digits in So Cal. AC is cold, engine at the top of the Cold range on the factory gauge.

[ubtripn]

Yeah, I know these trucks worked stock, part of why I have it. There is a variable somewhere causing it. Its only when it breaks 90. I guess it's time to check the timing again but I did that not long ago. Still considering the 2000 Grand Cherokee 19 inch electric fan install on my shroud in place of the mechanical fan.

[68is4me]

Some pics of your setup would help.

Do you have an IR gun? If not I would recommend getting one. Take actual temps of the radiator and t-stat housing when it is running hot. maybe you have a bad sender, bad t-state, poor circulation, or the set up is just wrong.

If you are running a stock v8 it should have no problem of keeping it cool.

[ubtripn]

I do and thank you - was going to ask where I should aim the ir dot and from what distance. What spot should match my gauge? I was thinking thermostat housing.

[68Gold/white]

I've seen many cars that have a pusher fan in front of the AC condenser. It runs constant w/ AC on. Not a bad idea.

ub, I'd install the pusher to run full time, w/ key on, see what happens. Could give you peace of mind, especially during hot weather season.

You may have a water pump issue, pumping too much too fast...What brand pump?

[67ChevyRedneck]

Originally Posted by ubtripn

The only issue I can think of is I got the ac shroud which is deeper and as a result the fan is 1/2 from the rad but DEEP into the shroud. (I want ac one day) I could try different spacers.

A fan deep into a shroud isn't pulling the air out of the shroud, it's now just spinning it inside of the shroud. The fan blades should be about 2/3 in shroud, 1/3 out.

Correct factory placement (this is a heavy duty 4 row, 7 blade clutch fan set up):

[biketopia]

Originally Posted by 67ChevyRedneck

A fan deep into a shroud isn't pulling the air out of the shroud, it's now just spinning it inside of the shroud. The fan blades should be about 2/3 in shroud, 1/3 out.

Correct factory placement (this is a heavy duty 4 row, 7 blade clutch fan set up):

Exactly this, I saw where the OP mentioned his fan was way deep into the shroud, it needs to be out of the shroud some or it's not going to do you any good, as you've found out. I bet if you pick up the right shroud and have the correct fan and clutch for what you're doing your issues will be solved. Also get that timing checked and make sure you're not running a little lean on the carb settings, that will cause it to run hotter as well.

[ubtripn]

Thank you both. I can try spacers to back my fan up. I am however pulling more air with the shroud, it is coming out of the center of the shroud very strong. I can make it better with your advice.

I also wanted to know if anybody ran a pusher in sequence with a mechanical fan so thank you.

[67ChevyRedneck]

I was just on the hot rod power tour, I saw A LOT of cars with stock type fans and shrouds being used combined with pushers in the front.

My truck has never run hot, even with the A/C on high in SC in August. I can watch the gauge go up to 205-210-ish in the summer when it's hot, then the thermostat opens, and it drops down to 195, stays there for a while, then repeats. If it's stupid hot out it will run a constant 200-205*

[midniteblues]

Originally Posted by 67ChevyRedneck

A fan deep into a shroud isn't pulling the air out of the shroud, it's now just spinning it inside of the shroud. The fan blades should be about 2/3 in shroud, 1/3 out.

Correct factory placement (this is a heavy duty 4 row, 7 blade clutch fan set up):

I agree.

A fan too close to the rad will just bounce the air off the rad and blow it back towards the engine. The air from the fan needs too go through the rad.

You did state that you feel a good amount blowing towards the engine.
Too close and it acts like it's blowing against a solid wall.

A clutch fan doesn't use spacers they have one built into the clutch.

I had this same problem after my BBC swap into my 67 with a long water pump and a new 4 core. The clutch of the fan was 1/2" from the rad and the blades were a lil' more than half way into the BBC shroud.

That's why I converted it too a short water pump setup.
After the swp conversion there was a drastic drop in running temps.

I do believe some fan clutches have different "depths". But I really don't think the difference in them will help you much cause your pretty deep in there.

And yes the timing can make a big difference in temps learned this the hard way after building the cammed 355 in my camaro.

Drive and tune,repeat,repeat,repeat till ya get it perfect.

[67ChevyRedneck]

You haven't said when it's overheating. Cruising down the interstate, at red lights, etc.

A trick for red lights (this is easier if truck is manual, but dropping in P works too for autos) is if it's getting warm at a redlight, rev the motor to 1500+ RPM's and hold it there. The factory clutch fans can pull some serious air at those rpms and should pull enough through the shroud to cool it down until the next light. That should help keep it driveable while you get this figured out.

You also didn't mention if you have A/C? If it's overheating without A/C and you have a 4 row and all the right fans/shroud... something is VERY wrong. Those radiators cooled big blocks with auto and A/C.

Total timing (with vacuum plugged off) should be 34-36* at around 3000 RPM (this is going off memory). With the vacuum plugged in it should add about 10* to that.

Also, what carb? Most carbs work well with the air/fuel adjusted to somewhere around 1.5-2 "turns" out from closed. Be very gently when "closing" them to see how far in they are, you can damage the seats. My edelbrock is set around 1.75 turns out. A vacuum gauge will help dial this in (and can also help dial in timing).

[ubtripn]

No ac, is heating up at lights. I have used the rev trick to some success. I have a Edlebrock 650 with fuel pressure regulator set to 5.5. When I set the carb I think I was pretty gentle.

[Stocker]

Originally Posted by 67ChevyRedneck

A fan deep into a shroud isn't pulling the air out of the shroud, it's now just spinning it inside of the shroud. The fan blades should be about 2/3 in shroud, 1/3 out.

Originally Posted by biketopia

Exactly this, I saw where the OP mentioned his fan was way deep into the shroud, it needs to be out of the shroud some or it's not going to do you any good, as you've found out.

Originally Posted by midniteblues

A fan too close to the rad will just bounce the air off the rad and blow it back towards the engine. The air from the fan needs too go through the rad.

You did state that you feel a good amount blowing towards the engine.
Too close and it acts like it's blowing against a solid wall.

A clutch fan doesn't use spacers they have one built into the clutch.

Agree with all of the above, these guys beat me to it but the fan really needs to be within the end of the shroud to be as effective as possible. As it is, there's air blowing out of the shroud but some of it is entering the same way it's getting out. Properly placed, the fan will pull maximum air through the radiator.

[biketopia]

Just read your other thread on removing the t-stat. You need to get your fan in the correct spot in the shroud. My brothers leman's wagon with a built 496 big block stays right 180 at cruise and no higher than 200 in stop and go traffic with a stock style BBC fan, shroud, and radiator.