An idea I have pondered about for extra cooling capacity

[schiker]

Has anyone ever heard of this idea or tried something along these lines ....


Taking the cab heater line and sending it to a front auxillary radiator in bumper nostrils then back either to cab exchanger and on to lower radiator hose or bypass the heater totally in summer (not best idea as air will cause corrosion issues.

I have thought of doing some Tee setup with valves to route the flow to the cab first in winter and to the auxillary radiator first in summer.

This might make lower bottom radiator hose a little cooler and allow a little more heat rejection capacity. Might even take out the orifice in quick disconnect to increase flowrate.

Would be similar to running cab heater to reject a little extra heat. Not all that pleasant of idea in 95F + summer heat.

 

[Big T]

I've seen a respected poster here say that the 6.5 cooling is not an issue of radiator capacity, but one of airflow.

 

[bk95td]

I like my idea of removing the transmission heat from the radiator. Why heat the coolant just before it goes back to the engine?
Getting the heat out of the engine compartment better can only help too as hood and fender louvers do.

 

[schiker]

I've seen a respected poster here say that the 6.5 cooling is not an issue of radiator capacity, but one of airflow.

Air flow has a lot to do with it. The more the better. The radiator design is a big ole trade off for "wetting" coolant to air surfaces vs too thick and reduced air flow. You can either increase air flow over a radiator or increase the surface area. Air flow at the expense of wind drag or load on fan is a draw back.

But the whole point is to reduce the temp of the lower radiator hose hence adding a little more capacity with some more surface area and decreasing any recirculated heat (in summer when the heater is not rejecting much heat at all it is just recirculating warm -temp??? coolant to the lower radiator hose).

I have also thought of adding more oil cooling to bumper nostrils in an attempt to remove heat from the "stack". Maybe a big custom frame rail oil cooler built into behind the bumper.

 

[Turbine Doc]

For my truck; bypass filtration for my oil, takes the oil filters out of engine bay so I get some passive cooling there plus 3 extra qts of oil in system, deep trans pan adds 3.75 qts extra trans fluid, and remote trans cooler addds maybe another 1/2 qt to sytem, spotlessly clean rad, and condenser fins, retuned fan clutch and plastic fan, and ZERO overheat issues with mine even hauling 18K on 100+F days

My burb with just a retuned clutch, waterpump, plastic fan also has ZERO overheat issues on 100F+ days with normal in radiator transmission cooling only.

 

[WarWagon]

Call Bill Heath. Call Ron Davis Radiator. They will both tell you this body style is too aerodynamic and has cooling airflow issues. Thicker radiator will not help.

Bigger better fan will. Clean radiator and oil cooler - esp condenser oil cooler interface of the mat build up is a must.

So will better HO water pump help.

Then you get expensive and as I have found unnecessary expense to keep it cool even at extended WOT.

 

[WarWagon]

I like my idea of removing the transmission heat from the radiator. Why heat the coolant just before it goes back to the engine?
Getting the heat out of the engine compartment better can only help too as hood and fender louvers do.

X2 on this idea. :thumbsup:

 

[schiker]

I agree its not a fix for a dirty stack and air flow is key to proper use of the exsisting radiator system. And a clean stack is paramount to the 6.5. I have cleaned mine and used foaming AC coil/fin cleaner to flush out lots of crud and replaced my oil cooler too and seen the back side of it. And I don't have an overheating issue. But have seen the ECT climb towards 195-200F when worked hard and I don't like worring about it.

Just extra capacity might delay or avoid the fan engagement and loss 6-15 HP off front of crankshaft to drive the fan when towing rolling medium long steep hills. No its not going to avoid fan on a mountain climb.

I thought about Bill's preference for single stat which blocks recirculation better and increases flow through the radiator when the stat opens.

I have wondered how much warm maybe hot coolant (summer and high ECT situations) gets returned directly to the lower radiator hose from the heater circuit. IIRC that is where the heater outlet hose returns coolant. And if you helped cool it more how beneficial it may be. And if it might help make the cab a bit cooler in summer if you took some of the heat out from under the dash / vent system to boot. No air shouldn't pass the heat exchanger but it still radiates heat into the duct I think.

I have also read advice to turn on heater if your vehicle starts to overheat.

Just something I have thought about.

 

[Detroit Dan]

I dont mean to hijack, but on a related note, I've had an idea in my head to help cooling for a long time, never got around to trying it. I never use the AC in my truck, I'm just not a fan of AC, I did spend a bunch of money years ago to first replace the seized compressor, the AC relay that failed next, then having it charged. It has since leaked out and I could care less, I just never use it. So what do you think about removing the AC condenser from in front of the radiator? Seems to me it would be beneficial to letting air through a little better, but I don't know enough about the math to know if it would be worthwhile or not.

 

[schiker]

If you don't use AC and don't figure on ever needing it (it does help in defrost mode too) then taking out the stack condensor would be beneficial.

In fact most anything you do to the frontal area to reduce restriction through stack and seal the stack will help some. Move the horn to behind bumper plug any holes in the sheet metal behind the grill that houses the radiator etc etc.

I helped play with different radiator cover protectors on a stationary engine enclosures and the effective open area has a lot to do with air flow.

The grill on these trucks have that big middle crosspiece with the bowtie on it that blocks some air. Its curved but still a fairly large cross sectional blockage. I have never done the math but an after market grill might be better.

 

[WarWagon]

I agree its not a fix for a dirty stack and air flow is key to proper use of the exsisting radiator system. And a clean stack is paramount to the 6.5. I have cleaned mine and used foaming AC coil/fin cleaner to flush out lots of crud and replaced my oil cooler too and seen the back side of it. And I don't have an overheating issue. But have seen the ECT climb towards 195-200F when worked hard and I don't like worring about it.

Step the entire engine cooling system colder with a 180 t-stat and Kennedy fan clutch. HP loss and MPG are possible downsides.

Just extra capacity might delay or avoid the fan engagement and loss 6-15 HP off front of crankshaft to drive the fan when towing rolling medium long steep hills. No its not going to avoid fan on a mountain climb.

These fans delay like crazy to turn on in the first place. Hot water return may help prevent shock cooling to the block. (Some designs like the gas LS7 use this.)

I thought about Bill's preference for single stat which blocks recirculation better and increases flow through the radiator when the stat opens.

I have wondered how much warm maybe hot coolant (summer and high ECT situations) gets returned directly to the lower radiator hose from the heater circuit. IIRC that is where the heater outlet hose returns coolant. And if you helped cool it more how beneficial it may be. And if it might help make the cab a bit cooler in summer if you took some of the heat out from under the dash / vent system to boot. No air shouldn't pass the heat exchanger but it still radiates heat into the duct I think.

I have also read advice to turn on heater if your vehicle starts to overheat.

Just something I have thought about.

Always good to think about things and improvements to the 6.5.

A good direction is to eliminate the delay of the fan clutch. It has to warm up the spring and then can take up to 2 min to come on after that. Hummer fan clutches that are on/off are one possibility. So is an electric controlled viscus fan clutch. Both are complicated. But they can steady the high and low temp swings you get loaded and hitting a hill.

Recall GM goes for MPG. A Dodge gets the same bad MPG loaded or not. This is because GM runs the fan 'when needed' with less ram air through the engine compartment vs. the referenced Dodge.

 

[SmithvilleD]

A relatively inexpensive way to see how some additional radiator/fan capacity might impact things would be to get a cheap/small import car's radiator & electric fan from a salvage yard. Parts cost would be very little & they're typically quite efficient little units.

It could be test mounted a number of locations: where folks mount the hanging ATA (would have to fab a little road debris protection if it worked well enough you wanted to retain it). I've seen a water to air IC setup with a couple heat shedding radiators angled up under the truck bed.

A less drastic step to try would be relocating the engine & trans oil coolers elsewhere so they get adequate airflow, but don't add to the cooling stack's airflow resistance & thermal load. This could potentially need short term fan cooling if you to heavy into areas where city traffic forces low speeds.

As relates a bit to TD's oil filter setups, I've got a 48 plate engine oil cooler (stock was 36 plt) & a remote dual oil filter setup, which makes for oil capacity of just shy of 12 qts. The 12 qts volume provides some buffer on how quickly hard running can drive oil temps up. An added benefit of keeping oil temps under control is retaining better oil pressure via less viscosity lost to higher oil temps. I would recommend an oil temp gauge w/ this type of setup as very cold winter temps (below 0) require some buttoning up of airflow thru the stack to ensure oil is warm enough to be an effective lubricant. I've considered adding thermostatic oil to cooler flow control but the only winter weather I saw be a too cool oil issue showed blocking/limited airflow thru the grille also helped the engine more easily maintain higher (more efficient) coolant temps.

These benefits & concerns would be even more relevant in the later engines with oil squirters/piston cooling.

 

[bobbiemartin]

This is/was a popular mod on Minis, especially before higher capacity radiators became available. Its not unusual for modified Minis to overheat, even at idle! The heater takeoff is at the back of the head and this is where the auxiliary radiator takeoff is located, a similar location to the blanking cover in the rear of the 6.5 heads. The water is plumbed through an auxiliary radiator, what is usually used is a heater core, although an aftermarket cooler would probably be better. A lot of people then run it to the lower radiator hose, but that is not a good idea. It needs to be plumbed back into the hot tank of the radiator (where the upper hose goes). This is because the water from the aux radiator may be hotter than the water coming from the main radiator and if it is, it will actually increase the engine temp, not exactly what you are trying to accomplish. If you discharge it into the upper tank, then you know it will be the correct temp. What you are trying to achieve is to lower the temperature of the water going into the radiator. By taking some of the water from the head and then cooling it before it gets to the radiator, you will lower the overall temperature of the engine.

This type of setup does work well on Minis and I would think it would work on a 6.5 as well. As others have said, you do need to place it in the airflow in a location where it will not add heat to the main radiator. One more thing, you are bypassing the thermostat, so in the winter you might want to disconnect or maybe plumb in a valve of some sort.

Now, I should point out that this mod has kind of gone out of fashion on the Minis as better radiators and electric fans have become commonplace. It really does add a lot of extra plumbing to accomplish what could probably be done with only a main radiator and proper oil/trans coolers, HO water pump, uprated fan & clutch, etc. I would only add the auxiliary radiator on a Mini or a 6.5 as a last resort after I tried everything else. Just FYI, when I say Minis, I'm talking real Minis, not those huge cars BMW makes these days.

 

[bobbiemartin]

I have also read advice to turn on heater if your vehicle starts to overheat.

Another old Mini trick. I have done this as well. In traffic, with 95-100 degree Florida heat, and no AC. However, its rather hard to explain to your wife why you are running the heater in the summertime.:smile5:

 

[treegump]

would removing the fan shroud help any? Or does the fan shroud help direct air flow? I was just thinking that if the fan shroud were to be removed that the air flow would not just hit the motor, but the cooler air may also spread through-out the engine compartment (and when it rains or water from the road would also spray through-out the engine).

 

[schiker]

The shroud keep the fan from swirling/recirculating and slipping too much when it pulls. It is also to help uniformly pull air through the radiator. They design the fan and shroud protrusion.

Have heard it helps to seal between the ac condensor and radiator if the factory foam gets deteroites and/or disappears. This helps seal the stack - fan pull.