Would a pump mounted fan help avoid overheating?

[YerDugliness]

My 5.0 in my Cobra has no fan on the water pump. It has a puller fan on the radiator (but no shrouding to force the air through the radiator yet). I have no overheating issues as long as I keep the fan on and keep moving, even just a little, but in this sweltering S.E. TX summer heat the traffic gridlock in downtown Houston sometimes causes the temperature gauge to go higher than I prefer.

I doubt if many of us run an engine mounted fan b/c of the parasitic nature, it must take a lot of horsepower to turn that fan, even with a clutch.

Considering that ventilation through the engine compartment is problematic for the Cobra in general, would running a pump-mounted fan help evacuate hot air from the engine compartment and therefore enhance cooling?

I hate to lose the horsepower, but it is certainly better than dealing with an overheated engine while I save enough to afford having Blykins build me a better one.

Cheers!!

Dugly

[ERA Chas]

No it's too far from the rad. Elmariachi has the definitive fan improvement thread so do a search here. He's also in Texas heat.

[bobcowan]

As I understand your question, you're thinking of an engine mounted fan not to pull air through the radiator, but to move air through the engine bay. That's an interesting thought.

As you move the air from the front of the engine to the rear, a little would go out of side vents, and the rest would go out under the car. In slow moving traffic, it might actually help. I'v never heard of anyone trying it, so it just might be worth a try.

Before doing that, I would optimize what you already have:
- Put a shroud around your fan so you're using all of the radiator, and not just some of it.
- maybe install a bigger 2 speed fan.
- Use a surfactant like Water Wetter or Purple Ice
- Make sure your timing and fuel mixture are correct.
- remove any underdrive pulleys

[Seagull81]

All you need is the shroud to fit your radiator and fan. Is the radiator sealed at the top to make the air go thru the radiator instead of over it? What thermostat are you using? I believe 185* is correct for carb. How much timing are you running? Have you pulled a plug or two to look at the ceramic part for it to be a little tan? If they are really white, you are running too lean. I'm sure there are more folks with ideas that will chime in.

[jhv48]

If the radiator is the proper size, the timing and carb are accurate, the thermostat is a 180 degree unit, then a high capacity puller fan (set to automatically turn on around 190 degrees) and a fully shrouded radiator will keep any 5.0 cool.

[Xavier]

My first drive in my Cobra - as a real test to overheating - was driving in So Cal traffic (some of the worse traffic in the nation) 112F temp, 50/50 fluid, no shroud, (1) large single SPAL fan pulling air off the back of the radiator, 180 thermostat with an 1/8" hole, running with the bypass hose - no issues - at all. My wife thought I was crazy to make this my first run, but I knew if it did not over heat then - it would not over heat period. This was typical stop-and-go So Cal traffic, 54 miles one-way to work not driving at 70 mph - more like the average of 45mph and then the sit and stop - sit and stop in traffic.

Shrouds are really nice and they certainly will help with air flow, but before you go thowing money away I would look at your current setup (timing, pulley, carb, air trapped within your system, etc.) before investing a dime.

Since then I have made many upgrades, front mouth shroud, dual pusher fans, changed the fluid, added purple ice etc. - but this was mainly for looks and the "why not" factor - but I know for a fact I never needed to do it to make certain my car would not over heat. When talking to people it seems like trapped air gets overlooked a lot in the manifold - and coincidently had not been mentioned yet.

[elmariachi]

$50 Taurus high output fan like this one from eBay. My side oiler idles at 90C max in traffic on the hottest days in Houston. This guy Dave is just down the road from you in Katy and makes turn-key harnesses for that fan for $75. Mark VIII Fan Install

You need a 100 amp alternator to handle this fan when it kicks on high.

[YerDugliness]

Thanks for the comments, guys! I'm pretty sure the timing and plugs are good (I just changed the plugs 500 miles ago and will look at the old ones as I retained them). I'm under the impression that the engine is a box stock 5.0 from an 1989 Mustang GT, just converted to carb, so I would expect factory pulleys...I'm 105 miles from it right now or I'd check. The radiator is fitted with a catch can for any discharge and there is never any fluid visible in it, so I think the radiator cap is OK (the radiator is a large aluminum Griffin unit, sourced from Keith Craft's shop up in Plano and is represented to be capable of cooling an engine producing up to 600 horsepower). I check the oil and coolant levels regularly and never need to add anything, it's always right where it ought to be. The puller fan works quite well, but if I turn it off the coolant heats up quite quickly even at low speeds (<10 MPH), so I know it's having a positive effect.

I like the idea of the Water Wetter or Purple Ice and have been thinking it was time to change the coolant. Will the WW or PI work with the newer antifreezes that are not ethylene glycol based? If so, I'll give it a try.

Originally Posted by bobcowan

As I understand your question, you're thinking of an engine mounted fan not to pull air through the radiator, but to move air through the engine bay. That's an interesting thought.

As you move the air from the front of the engine to the rear, a little would go out of side vents, and the rest would go out under the car. In slow moving traffic, it might actually help. I'v never heard of anyone trying it, so it just might be worth a try.

You are corrrect, Bob. This is my "scheme". Keep in mind the coolant temp has never exceeded 220F, it's just that we all know about the airflow issues with the Cobra's crowded engine compartment (not that those sidepipes help anything, either, with 8 header pipes all radiating heat within the engine compartment). Obviously, the fan could be removed for 3 seasons of the year, it's just that 4th season that cooks us Cobra drivers down here.

@ Elmariachi: I've heard about your Taurus fan fix, it sounds great and if it becomes a problem I'll certainly jump on it. I live about 25 miles from Katy (in Rosenberg, about 20 miles SW of Houston on U.S. 59) so the trip to Dave's would not be a problem....in fact, the Cobra has probably been driven in Katy more than it has in Rosenberg, as I use to work there and have friends there I visit.

@Seagull 81--no, there is no shrouding for the radiator to keep the air moving through it, although I suspect that large puller fan does a fair job.

For now, I think I know what is needed....a combination of a shroud, careful management of engine tune, and additives to the coolant, perhaps even wrap the primary pipes with some sort of heat tape. For now, the idea of just slapping a clutch-type fan on the front of the water pump was the easiest (other than the Water Wetter/Purple Ice). When I start upgrading the power, I suspect the problem will grow into a bigger issue.

Thanks for the suggestions, guys. I'll let you know how it goes when I get to work on it.

'Till then, keep the faith, and if anyone has more suggestions I'd be glad to hear them.

"...onward thru the fog", as they say!

Cheers!

Dugly

[jhv48]

Just a thought, if that 5.0 was an f/i engine originally, then it had a 195 degree thermostat.
Change it to a 180 and you will be fine with a shroud added.

[bobcowan]

Originally Posted by YerDugliness

The radiator is fitted with a catch can for any discharge and there is never any fluid visible in it, so I think the radiator cap is OK (the radiator is a large aluminum Griffin unit, sourced from Keith Craft's shop up in Plano and is represented to be capable of cooling an engine producing up to 600 horsepower).
Dugly

This statement caught my attention. The catch can on a modern engine does more than catch overflow. As the system heats up it expands, and needs a place to go. It ends up in the catch can. As the system cools, it contracts. The fluid should get sucked back into the system.

The catch can is actually part of a closed system. When cold, there should be an inch or two at the bottom of the can. When hot, the can should be about 1/2 - 3/4 full. If that's not happening, you're probably low on fluid, and the cap is probably bad. Caps don't last very long.

Surfactents like WW and PI work with any coolant.

The thermostat sets the minimum temp, and have very little to do with max temps. If it runs a steady 210*, the thermostat has no effect. If you're going from 195* while moving to 210* while sitting then a lower temp thermostat (like 180*) might gain a bigger buffer zone for the swings, but still won't effect max temps very much.

[elmariachi]

Originally Posted by bobcowan

This statement caught my attention. The catch can on a modern engine does more than catch overflow. As the system heats up it expands, and needs a place to go. It ends up in the catch can. As the system cools, it contracts.

Only if you are using the proper radiator cap. There are different caps for open and closed systems. You need to know which you have if you are counting on the system to contract and draw the contents of the catch can back in after it cools. Cap pressure ratings can also affect cooling as well.

[badrich]

Another vote for a big puller fan with a nice custom shroud and 180º thermostat. I don't run the fan until I leave the highway, then I flip the Lucas (?) switch and the coolant gauge stays at 180º. So far. Rich

[madmaxx]

Make sure your temp gauge is accurate.

[Paul F]

I have a puller fan with no shroud on a 351W; thermostat controlled. At first, it overheated very quickly. I added water wetter. No more problems, even in the scorching desert heat.

[YerDugliness]

Originally Posted by Paul F

I have a puller fan with no shroud on a 351W; thermostat controlled. At first, it overheated very quickly. I added water wetter. No more problems, even in the scorching desert heat.

That's a huge endorsement! In my case, my fan is switch controlled, so I am the thermostat....no problem, I keep a good eye on my gauges.

Other than the thermostat issue, your setup is exactly like mine. However, my engine doesn't overheat unless it's stop-n-go traffic on a hot day, and even then it's never gone over 220 degrees. I'll definitely give the WW a try!!

On another issue, although I doubt that I have any air pockets trapped in the manifold I would like to check that issue. For those of you who have installed bleed systems on their intake manifolds, would you mind posting a photo of it? Trapped air is a big issue on most of the automotive forums I frequent so I want to address that possibility.

I don't have a heater (yet), so no air entrapment issues there.

@MadMaxx...I'd like to check the coolant temp sending unit.....but how? It's not like a thermostat, where I could take it off and immerse it in a pot of boiling water. Any advice would be appreciated.

Thanks, folks....thermostat check (actually, replacement, they're CHEAP!) and Water Wetter will be my first step....we'll see how that works, if it is still an issue I'll get busy measuring and bending some aluminum for a shroud.

Cheers!

Dugly

[Jerry Clayton]

You haven't said(or I missed it), but your comments about horse power and converted from efi to carb--did you by any chance use an underdrive pulley set ?????

[YerDugliness]

Originally Posted by Jerry Clayton

You haven't said(or I missed it), but your comments about horse power and converted from efi to carb--did you by any chance use an underdrive pulley set ?????

I don't think so, Jerry. I'm over 100 miles from it right now, and I'll check when I get home, but I believe the only thing they did when they swapped over to carb was change out the intake manifold for an Edelbrock and slapped a Holley on it (which made it run TERRIBLE, it was a 780 CFM). The most recent owner switched the Holley for an Edelbrock Thunder and it really screams now.

Of course, they eliminated the A/C compressor and the PS pump. All it has now is the alternator.

There are a lot of characteristics regarding the build that lead me to believe that it started life as a drag racer....aluminum fuel cell with the foam blocks built in, Mallory equipment (billet fuel filter, Mallory fuel pump, Unilite distributor and Hi-Fire coil), 9" Ford live-axle rear end, Brembo disc brakes on all 4 corners, and the most perplexing thing is the way the front and rear bumpers are mounted--there is only one bolt mounting the bumpers to the frame on each side of both bumpers, not two like every other car I've ever seen. I think it was an easy way to mount push bars for the trip back to the pits. The frame was built by Ron Godell Race Cars in Tulsa, OK (I suspect he completed the build, too). When Ron Godell died his heirs sold the replica to a used car dealer, and it was bought from the used car dealer by the owner two owners back. I have spoken to him, that's how I know where he got it and how.

It's quite likely it might have had a big-block in the past, but at some point it was swapped for the current 5.0/T-5 combo.

Cheers!

Dugly

[YerDugliness]

Originally Posted by elmariachi

$50 Taurus high output fan like this one from eBay. My side oiler idles at 90C max in traffic on the hottest days in Houston. This guy Dave is just down the road from you in Katy and makes turn-key harnesses for that fan for $75. Mark VIII Fan Install

You need a 100 amp alternator to handle this fan when it kicks on high.

Question here....if I were to go with the Taurus fan system, are all Taurus/Sable fans 2-speed?

Houston has "Pick-a-Part" self-service salvage yards all over the place...might be able to find one at a better price.

Never hurts to try to save some $$

Cheers!

Dugly

[elmariachi]

Originally Posted by YerDugliness

Question here....if I were to go with the Taurus fan system, are all Taurus/Sable fans 2-speed?

No. You need to find one with three large wires coming from the motor, and the preferred one is either the one I show in this thread or the sister Mark VIII fan like this one.

The Mark VIII is deeper and has a chopper-style blade. It supposedly moves even more air than the Taurus fan, don't know for sure. Either way, get the harness-side connector too if you can.

[elmariachi]

I wouldn't discount some of the other comments here, especially Jerry and the pulley sizes. I had a new engine fresh from the builder so I was relatively sure I didn't have an engine issue, but purely a heat dissipation issue. Sounds like you know less about this engine than I did mine, so I am just sayin'....cover all your bases.