Cooling with heater

[GroversXJ]

This may sound crazy to some of you but I had an idea for cooling the engine while wheeling in the summer (115+ deg temps) out in the desert heat with the A/C yet still keeping the wife and kids cool inside.

I was talking with a co-worker about how to keep his ultra-4 xj cool and this came to me the next day. I was always able to drop engine temps when it overheats by kicking on the heater as a last resort, so I thought I could roll with this idea. I figured I could hook up another heater core and an extra electric fan to pull extra heat out of the engine when needed. I have some hood vents so maybe I could mount it up under the hood or even if there was enough space inside the cowl I could mount it inside there rather than my intake (smog won't let me get rid of factory airbox). Does anyone have pics of the space available inside the cowl? Would there be enough room in the cowl for a heater core or even mount the core inside the engine compartment against the firewall and just mount a fan inside the cowl. Then force air from the cowl area thru the heater core into the engine compartment and out.

Sorry I can't access my xj right now to open up the cowl and look for myself. I figure I could add in some valves in the heater hoses to route the coolant thru the extra core only when needed like the valve already under the hood that bypasses the core when your not running the heater.

What do you think? Am I crazy? I'd like to think so...

 

[ehall]

The heater core is essentially a small radiator, transferring heat from the coolant to the air that blows over it. Yes, you can add more radiators, yes they will cool the engine a little more. Or you can add more / better equipment at the main radiator

 

[GroversXJ]

OK, just to satisfy all the typical "upgrade your standard cooling equipment" folks, here is what I have done already. It's a 90 Cherokee so I converted to the newer radiator design and put in a good (CSF 3 row, if I remember correctly) radiator 6 years ago and used the jeep maybe 2000 miles a year since then. I kept cracking the pressurized overflow bottle. I also put is some hood vents and a new thermostat and radiator cap. The engine stays cool at all times except when I'm wheeling slow in the summer (110 degree F or higher) and have the A/C on. So the cooling system is healthy, but just not enough air flow at low speeds. The stock mechanical and electric fans are in place. I wired in a switch to turn on the electric fan when needed but its comes on automatically with the A/C anyways. I don't mean any disrespect, this is just an idea to add extra cooling surface when needed.

 

[Demonoid369]

How's your clutch fan? That is the biggest air puller to help cool.

 

[IslanderOffRoad]

Do the zj clutch fan

 

[GroversXJ]

My clutch is likely the stock one that came with the vehicle as I've never changed it and the previous owner didnt either but that's just the last 15 years. I have heard replacing with anything but oem new the clutch quickly fades to worse than old oem.

 

[md21722]

I bought my 01 XJ in Reno back in the summer of 2004 and drove it home across the NV/CA/AZ desert. I never had any high engine temperature problems, even sitting in construction traffic and I never turned off the A/C on the grades where its advised. Granted my 2001 temperature gauge is a bit more dumbed down for temperatures past 210F, but the Jeep never complained or got "warm".

Window tint & making sure your cooling system is operating at the level it left the factory new is what I'd be focusing on. The fan clutch degrades over time and can pass all those tests where it stops fast, spins, etc but still not blow enough air. Southwestern/desert dust can clog condenser and radiator fins. If after the factory system is running as designed, you'd like more cooling, then I'd look to the Mopar HD radiator which has a thicker core and maybe some fan improvements. Some people add hood vents. You may want to check the tranny temps and look at an auxiliary cooler for the transmission.

 

[Johnnie Walker]

Do the zj clutch fan

This^^ ZJ non-MAX cooling fan clutch. Many have done it, and it just works. Gives you more airflow.

 

[GroversXJ]

What is a non-Max fan clutch?

Apparently it's difficult to think outside the box here. It seems every cooling issue thread has something about hood vents, a different radiator (this brand or that brand depending on the day), or try this electric fan or that fan clutch.

Even when my old radiator was partially plugged I could always turn the heater on to bring down the temps when it was overheating. This is why I was thinking of using the heater core as an aux radiator and I know it can flow enough fluid to not cause issues. Remember this idea was brought about by looking for more cooling capacity in a stock class ultra 4 race car that must keep a radiator in the stock location, but there isn't any rule saying something else can't also be used to cool the engine. So I figure if it may be able to cool a race car it should be able to cool my rig driving slow in the summer with the A/C on.

That's where I'm coming from anyways.

 

[jk_surgeonfish]

I understand what you are trying to do and it probably would work. Where are you intending to mount it?

My issue mostly lies when climbing hills towing w/AC on. I have all new components on my 99 and it consistently will jump to 138 or even to 148 when going up hill. Yes, I am in 3rd gear when towing. The combo of lift, big tires, extra weight, living in Northern AZ makes cooling a challenge. My thoughts were to try a misting system in front of radiator to add some humidity to the air and get some water on the radiator. Just set it up with a small tank, washer pump and a switch to turn on off. I know they make kits for RVs. Wondering how much cooling effect one would get????

As far as mounting the additional cooler for radiator what about underneath the bumper like GoJeep did. See link:http://www.go.jeep-xj.info/HowtoAutoCooler.htm

With the way GoJeep did it you may even find a small fan to pull air through it.

I may do this to my trans cooler to get more air flow over the radiator for cooling.

 

[GroversXJ]

I would mount it up on the firewall where some folks cut a hole into it to gain access to the cowl area for doing cowl induction air intake relocation. I thought I'd mount a fan in the cowl and blow air thru the aux heater core into the engine bay. I have seen an image of someone mounting a cooler to the hood under a vent that could work too.

I have already mounted a power steering cooler behind the bumper on the cross member, so that real estate is already taken for me.

I think spraying/misting water on the radiator would work really well but unless you used distilled water you may get water deposit's building up on the radiator and it would hurt its cooling ability eventually. I thought about this once or twice before too but ruled it out for me eventually.

 

[mtbxj87]

what about a oil cooler?

 

[rockclimber]

sounds like you have all the answers.

go do it and report back.

 

[rockclimber]

I understand what you are trying to do and it probably would work. Where are you intending to mount it?

My issue mostly lies when climbing hills towing w/AC on. I have all new components on my 99 and it consistently will jump to 138 or even to 148 when going up hill. Yes, I am in 3rd gear when towing. The combo of lift, big tires, extra weight, living in Northern AZ makes cooling a challenge. My thoughts were to try a misting system in front of radiator to add some humidity to the air and get some water on the radiator. Just set it up with a small tank, washer pump and a switch to turn on off. I know they make kits for RVs. Wondering how much cooling effect one would get????

As far as mounting the additional cooler for radiator what about underneath the bumper like GoJeep did. See link:http://www.go.jeep-xj.info/HowtoAutoCooler.htm

With the way GoJeep did it you may even find a small fan to pull air through it.

I may do this to my trans cooler to get more air flow over the radiator for cooling.

dry air will cool better. misting the radiator would be worse unless you could somehow keep the water cooler than the air.

 

[rockclimber]

This^^ ZJ non-MAX cooling fan clutch. Many have done it, and it just works. Gives you more airflow.

its a myth.

it may turn the fan a little harder to "give you more air" but it also makes the engine work harder, thus heating the engine up more.

same psuedoscience the triple electric fan is based on

a functioning OEM clutch works fine.