overheating

[HotWheels]

If you didn't live in a freeze zone I would bypass the radiator for your tranny cooler. But since you do live in a cold zone make sure you go through the tranny cooler first and then through the radiator. Make sure you have air pulling/pushing through the tranny cooler. If you are not using a 7 blade fan, BC bronco has a really good mechanical fan if it will fit but is noisy as hell. it will pull enough air. I run the factory 7 blade but use a smaller 289 water pump pully but its on a 302 engine. Gearing will help alot and will allow you to kick it in first gear and get the rpms up while going slow thus circulating the coolant much better. with out the proper gearing you dont have enough torque to pull the load so you just build heat in everything. Engine/ exhaust/ coolant /tranny everywhere. The difference is night and day running 4:11 gearing over 3:50 gearing when running 33's everything doesnt have to work so hard so you dont build excess heat in the first place. Especially since you live at altitude you dont get a break like flat landers do. When i fill a coolant system i run with the cap off and the front of the truck up on ramps or a curb so there are no low spots in the engine get, the system hot and full then cap it with a 16 lb cap.

so ur saying 4:11 is better than 3:50 with a c4 and 33s?

 

[Rustytruck]

Big time better. with a 351 the minium would be 3:73 unless your at sea level running on the flat highway. I ran 3:50 gearing with the origional 28 inch tires,30 inch tires, 31 inch tires,32 inch tires, and about a year on 33 inch tires and after getting fed up and having some extra cash I changed the gearing to 4:11's 2 years ago ad dont regret it and the change is like night and day. Of course I have a stock engine and it is typical to be at sea level in the morning and run trails at 8,000 feet during the day in 105 degree heat. My engine turn 3,200 rpm at 70 which for most is a bit high but is about 300 rpm below peak torque so the engine is at its most efficient state.

 

[HotWheels]

so let me make this clear. For a daily driver 351w w/c4 4:11 will make it more streetable? Improve MPG, etc?

 

[Rustytruck]

Yes if it is a stock smog, factory production engine running anything more than flat ground and you have an average moderately heavy Bronco. If you plan to tow anything or climb anything i would highly recomend changing the gearing. Now if you want to build a hot motor and turn 6 grand to get around town then the gearing is too much and you would be happier with 3:73. There is no real clear answer if you havnt settled on what you have and where the whole truck combination is going to end up.

 

[HotWheels]

rusty..let me tell u what I have...I need advice ok? should we do this in another thread or PM? bbl

 

[Rustytruck]

Send me a PM so we can go into details without a bunch of hassel then start another thread and ask for other opinions. There are alot of factors to concider and then exclude what you wish and then go from there.

 

[67EB_in_619]

So with 10% coolant, 90% water, new TSTAT I am running at about 210*.. just under. would prefer 195... but I am running a c4 cooler in front of the rad and that can explain some of the temp difference.

I would suggest lowering your mixture... I dont think you need 50/50 to keep from freezing. Also .. the rad cap pressure is a big deal.... dont overlook it as a possibility. I still want cooler temps.. but I think I will need to relocate the c4 cooler to do that.

 

[HotWheels]

So with 10% coolant, 90% water, new TSTAT I am running at about 210*.. just under. would prefer 195... but I am running a c4 cooler in front of the rad and that can explain some of the temp difference.

I would suggest lowering your mixture... I dont think you need 50/50 to keep from freezing. Also .. the rad cap pressure is a big deal.... dont overlook it as a possibility. I still want cooler temps.. but I think I will need to relocate the c4 cooler to do that.

what do u think of the B&M plate cooler? I was thinking of placing that on the passenger innner fender with spacers since it has its own fan? I am going to run it in the return line of the c4 form the radiator cooler.

 

[77pony]

A couple people have mentioned the rad cap. What would make it overheat, release too early or too late? I can hear mine blow at about 210 by my dash gauge. -al

 

[Lttrbox]

I got one similar to the BC sells. Had one in front of the rad before and got me heat. I also had fan shroud problems - at idle and low speed this thing actually pushed hot air through the rad to the front then sucked the hot air back through (kinda defeated the purposed of the radiator). The moral of the story (in this case) was make sure you dont have a spot created by a body lift, fan, and shroud that tends to hold up air. Since I fixed this Ive had mostly driver error problems.

Mounting a cooler on the inner fender huh? Doesnt the C-4 have that littler vent in the center top of the trans body. If you put that cooler up on the inner fender and then get the trans filled, wont it start leaking out that vent when you you shut it off. I put a vent extension on there and ran it up the fire wall (lots others doing this too).

 

[HotWheels]

I got one similar to the BC sells. Had one in front of the rad before and got me heat. I also had fan shroud problems - at idle and low speed this thing actually pushed hot air through the rad to the front then sucked the hot air back through (kinda defeated the purposed of the radiator). The moral of the story (in this case) was make sure you dont have a spot created by a body lift, fan, and shroud that tends to hold up air. Since I fixed this Ive had mostly driver error problems.



Mounting a cooler on the inner fender huh? Doesnt the C-4 have that littler vent in the center top of the trans body. If you put that cooler up on the inner fender and then get the trans filled, wont it start leaking out that vent when you you shut it off. I put a vent extension on there and ran it up the fire wall (lots others doing this too).

Already extended the vent to firewall. good catch though. how did u figure the hotspot thing out?

 

[chuck]

I think adding a ele. fan is a good idea but replacing the man. fan with an ele fan is not. Either way the ele fan will not fix your problem. My .02. Before you start spending money be sure you check and correct all of the following.
1. Water pump pulley smaller than the crank pulley
2. Hi flow water pump
3. No vacuum leaks
4. air/fuel mix correct
5. timing correct
6. T-stat good 180
7. Good mechanical fan the right distance into the shroud
8. Good shroud
9. Belt adjusted correctly
10 a 16-18 lbs. cap in good shape
11. a recovery system in good shape
12. Check the gauge for accuracy. I don't care who made it or how long you have used it
Do not assume any of the above. check. If all are O.K. then change your radiator. When looking for a radiator do not look at the price first.
If you decide to go with the ele. fan only I would like to know how it turns out. Without changing anything else.

 

[Lttrbox]

how did u figure the hotspot thing out?

My cooling issues ran a long time because I was continually modifying things and never really had the same rig. Believe it or not it was really a fluke. Last summer I was out toying with my rig after getting back from Moab (with a vapor lock issue) attempting to trace the vapor lock. I was crawling under the rig to trace the fuel lines and happen to sick my hand on the bumper near the rad outlet. Huh, something felt weird there with the air. I went and got a shop towel and ran a corner of it up and down the radiator (all locations).

Holy crap, airs going the wrong way. Toward the front though the rad near the outlet and then back through the rad higher up. Geeze, WTF, Humm. Well, when I first got the rig, the PO had put a 2 in body on it. He had built some little weenie brackets to lower the schroud. On the old worn motor that worked, but I had since rebuilt and beefed it up some. So, I built a couple of brackets to lower the schroud and block off some huge holes left by lowering the bracket. Well, that created a big pocket formed from the radiator, schroud, and my bracket.

As it turns out, the flex fan I got in there would create just enough pressure at the rad outlet (at crawling speeds) to push the air the wrong way. I could rev the motor up and no help (in fact made it a little worse). If I drove the rig up to say 5 to 10 mph, the pressure would reverse and the temp would drop to normal in just a couple of minutes or less. Dam thing stumped me for a long time.

Believe it or not the GF said take that 1/8 steel over there and make another one. I thought okay. Half a day later, I had one built up, adjusted for the body lift, took out the pocket and got the fan to do what its supposed to do. Havent done the hot weather routine yet, but the hammer trails late last year gave me a warm fuzzy. Its nice to wheel with no motor worries.

 

[Rustytruck]

Also add minium 16 lb cap and an over flow bottle so you can fill the radiator to the top.

 

[chuck]

Also add minium 16 lb cap and an over flow bottle so you can fill the radiator to the top.

Oops, I forgot 10 and 11. thanks

 

[supermottl]

Let me put in my experiences:
I decided to start playing with electric fans when my temp would slowly rise up to and over 200* while waiting in traffic in balls hot summer. I had 302, mech fan no shroud, manual tranny. On hiway and just cruising it was always rock solid 180*.

The first toying I did was remove the mech fan, and put on a brand X 16" puller off ebay for 45 bucks. Got a fan controller and set it to turn on at 190 (Autometer mech temp gauge = pretty accurate). It would creep up around 200* before stabilizing and coming back down to 190* but never cooler even w/ a run on hiway. Around town, the fan was always on.

Next, decided to take someone's advice and get the Flex-a-lite Scirroco dual fan with integrated shroud. It covers 80% of the radiator and is a nice thin unit. Plenty of room between water pump and fans. 1st real run was last weekend, and ambient temp was 60-70. My temp on hiway wasn't very good. 20 mile trip and the temp would slowly climb up to the 200* mark and sustain - fans on constantly.

So, for my two attempts at electric, I'm not impressed. This week, I plan on getting a shroud (no Body lift) and putting my mech fan back on. It has not been an expensive experiment, but still... I don't see how WH JUST runs the 16" spal.. dunno if I beleive it...? Good luck to them. If anyone has Q's lemme know.
steve-

 

[md_lucky_13]

My step dad is running a 16" Spal electric fan on his rig. It is running a hot 406w (bored/stroked), with all kinds of goodies. He went so far as the seal the vents in the hood.
Well, it gave him headaches. The thing kept over-heating out on the trail. I finnally convinced him that he needed to open up his engine compartment and create some air-flow.

After doing so, he has not had any problems over-heating. The ambient temperature has been cold, and it has mostly been snow driving, but his rig has stayed 180* every time.


I am running 2 12" Proform electric fans. They pull about the same CFM as the spal (2400). When the temp was below 70*, It was impossible to stay above 180* with the fans running. I was constantly turning the fans on and off, on and off, just trying to stay up to temp. I have an adjustable fan controller hanging on the wall, and it should take care of that problem.


I think the biggest problem people have with electric fans is that they do not get fans that pull enough CFM. Not to bag on Chuck by any means, but the fans he offers on his site, in 12" (which are comparable to what I am running) only pull 880cfm. If you run double 12" fans using those, you only have 1760cfm of air movement. The absolute lowest number I found for a "small block v8" while doing research was 2000cfm, no AC. Most of the places recommend at least 2200+ cfm for a V8 setup. (off of Derale's site, they have a bolt in 5.0 mustang fan that pulls 2200cfm air).

The fan that Wild Horses offers pulls about 23XXX cfm. It should be enough to cool a stock 5.0 mustang motor, no problem. Not to mention if you step it up and open up your engine compartment..

James duff offers a 16" fan that only pulls 1450 cfm of air. That is WAY too little CFM, and I would bet dollars to doughnuts that if you run that fan, you will over-heat every time.

I did a ton of research before I finished up my cooling system. When I broke my motor mounts, that mechanical fan ate my radiator for lunch. A VERY expensive "oops." I did not want to ever worry about putting holes through my radiator again, so I went electric. I do get very verticle very often, and I know it would probably be a continous problem. That is one of the major reasons I decided to go with electric fans. A good electric fan is not cheap, but if you are interested, make sure you get the highest CFM you can possibly find... good luck!

 

[74bronc]

I tried a 16" Autozone special electric when I built my 351W and it never overheated, but it constantly ran hotter than I would've liked. After a tip posted here, I researched out a Zirgo 16" puller that is supposed to pull 3300cfm. I think I might give that one a try only because I like to experiment. An online store has them on Ebay, NIB, for 90 bucks. If there is an electric fan that will work, it might be this one.

 

[77pony]

This site is so incredibly helpful.

It goes in for 4.11's Monday, and I'll put a new 16lb cap on and then see where I am. -al

 

[67EB_in_619]

what is a good distance from rad to fan?

It is hard to see in this pic.. but here is my set up.... the fan is outlined in yellow