Got serious about cooling issues

[SCW]

It's been near or over 100 degrees here for two weeks now, and I just can't seem to keep my Jeep cool, especially when towing my little trailer which only weighs about 1500# loaded. I usually do OK in town, traffic gets bad and towing over mountain passes is a joke at 100F, so here is what I have done.

At first I tried a 3-row radiator that I picked up used locally for $40, I figured if it solved my problems I was ahead that much money, but it didn't work. Next step was a new 2-row radiator and new water pump. Still won't stay cool very well in traffic if it's over 95F outside-

Here is my latest work. First step was to get the "right" heater core, after searching around quite a bit I decided on one for a mid-90's Ford Explorer, it's 2" thick, 6" wide and 7 1/2" long, and new from NAPA was $25. My first choice was actually the rear core from a mid-90's Tahoe as it is longer and only an inch thick, but the price was double.

First step was to mark the hood for the hole- I wanted to mount the core in the hood with a fan below it that would be temp controlled. I marked the hole with enough room around the edges to allow room for some nice padded weather stripping that would keep the vibrations from wearing on the core. Dimensions of the finished hole would be 6 1/4" x 7 3/4", but more than that I also cut inside of that dimension by 1/2 to leave material to fold back to provide rigidity. It works well, the panel is more rigid than the uncut side.

Marked the hole, then taped it off-

Made sure to protect the underside from sparks, not too much of an issue because the factory insulation was still on, but just to be safe-

I used an angle grinder with a cut-off disk-

After cutting the inside, I drilled hole tight to the corners-

Which allowed me a place to grind to without getting carried away-

Built some mounting brakets out of sheet metal and used plenty of weather stripping to avoid wear on the core-

This is what it looks like mounted from the inside-

Next step is to install a 10" fan (1250cfm) under the core and run it on a thermostat- Fan shipped two days ago, should be here early next week.
http://cgi.ebay.com/ebaymotors/ws/e...m=260010636896&ih=016&sspagename=STRK:MEWN:IT

After that I'll be installing hood scoops on both sides, but with the scoop turned backwards so that the fan will blow the warm air towards the windshield. On the drivers side I'll just cut a small area for venting and place a twin scoop on that side. Here are the scoops I'm using, they will also be on next week, but not painted.
http://cgi.ebay.com/ebaymotors/ws/e...m=290012085475&ih=019&sspagename=STRK:MEWN:IT

As of right now I can't do much else, I'm waiting for the fan and scoops, but I did get some (hopefully) good cement to fasten the scoops to the hood, and for now I'll run the fan on the same adjustable thermostat that runs my electric fan.

After this I shouldn't have trouble cruising over mountain passes with my trailer, but I'm headed to the Utah-AridZona border next weekend with my trailer, so that will be the acid test.

 

[SCW]

Some shots of the outside-

 

[meatplow5150]

Wow. Interesting idea to use a heater core for aux cooling.
You didn't mention if you were using OEM fans, and if so, if you had checked/replaced the fan clutch and aux. electric fan. Also, have you checked/replaced the thermostat? It could be stuck closed. Just a thought...

I was having some overheating issus too once summer hit. I had a wimpy dual electric setup that worked fine in the cooler months but couldn't cut the mustard in the heat. I went back to the oem setup with a new fan clutch and haven't had any problems since.

 

[blue95xj]

Wow. Interesting idea to use a heater core for aux cooling.
You didn't mention if you were using OEM fans, and if so, if you had checked/replaced the fan clutch and aux. electric fan. Also, have you checked/replaced the thermostat? It could be stuck closed. Just a thought...

I was having some overheating issus too once summer hit. I had a wimpy dual electric setup that worked fine in the cooler months but couldn't cut the mustard in the heat. I went back to the oem setup with a new fan clutch and haven't had any problems since.

I was thinking the same thing new fan clutch fixed my problems a year ago and still goin' cool

 

[SCW]

I'm running a Pro-comp 16" electric fan with thermostat control. I love the set-up, I get quite a bit more power, several miles per gallon and it's quiet as a field mouse. The fan is rated at 2750cfm, but I'm not buying it, there is no way this fan puts out near that much air. I'm shopping for a better fan, but they pretty much all look like the same fan renamed.

In short, I think the fan is SOME of the problem, but I'm getting warm at 75mph on the freeway too, and there is plenty of air going through the radiator at that speed, so there is a lot more than just an e-fan issue here. Also, at idle this fan does but out a lot more air than the mechanical fan would at idle, so that should be an improvement.

Mostly, I want the entire system beefed up to handle the mountains with a trailer, and I don't want to have to take it easy. Last time I went over one of the large passes here without my trailer I flew past a chevy that was blowing steam all over, I don't want to be that guy, lol.


EDIT- I just checked, my fan is quite a bit thinner than most of the 16" fans on the market, maybe I'll try one of them and see if it's any better. At $60-$100 each it's an expensive experiment though-

 

[meatplow5150]

If you're still getting hot at highway speeds, it's probably not the fan. And if it is thin and has plenty of clearance between it and the fan belt/pulleys, stick with it. I had one that barely cleared and the engine went into it dropping off of a small rock ledge causing it to self-destruct. Sounds to me like you have other issues here. Try flushing the system and replacing your thermostat, if you haven't done that recently. Deposits can build up in the block as well as the radiator, which would make everything less efficient. I have read here that someone filled their system with a vinegar and water solution (give the 'ole girl a douche! :roflmao: ) and run it that way for a few days, then flush and refill with normal coolant. The vinegar will dissolve any deposits in the system.

 

[mrbill3]

It's been near or over 100 degrees here for two weeks now, and I just can't seem to keep my Jeep cool, especially when towing my little trailer which only weighs about 1500# loaded...

What kind of trailer are you towing that only weighs 1500# loaded?

 

[SCW]

I have read here that someone filled their system with a vinegar and water solution (give the 'ole girl a douche! :roflmao: ) and run it that way for a few days, then flush and refill with normal coolant. The vinegar will dissolve any deposits in the system.

That was me The block is about as clean as a whistle, when I had the water pump off last night I looked inside as close as I could, not a touch of deposit to be found. Thermostat is new, hoses are new, now the radiator is new, etc. When I hold my hand in the air stream of the electric fan I'm a little underwhelmed though, not what I was after.

I also run a fairly large trans cooler to support the stock cooler in the radiator, and whenever I get around to building my front bumper it will have a small grill in it for the engine oil cooler, but that won't be functional until I also have steel lines for it.

So far my cooling issues have only been when the temps have been over 100 outside. I anticipate this mod when finished will absorb any deficiency I have, but I'll know for sure in a week from tomorrow.

What kind of trailer are you towing that only weighs 1500# loaded?

A small utility trailer with just enough crap on it to get my family into the woods overnight. Pretty small amount of stuff, but bigger than I have space for in the Jeep with all of us.

 

[hadfield4wd]

A small utility trailer with just enough crap on it to get my family into the woods overnight. Pretty small amount of stuff, but bigger than I have space for in the Jeep with all of us.

Wow that's overnight. Looks like enough for a week. I can get all my stuff in side with three kids and a wife for a weekend. (The spare is on the roof). That includes spares and tools. Can't see out the back window and the sleeping bags are at the kid's feet.

Matt

 

[Bouncy]

Cooling info and ideas.

I converted my 90 XJ to the open system.
3 core radiator
Stock 195 t-stat
New stock water pump
Added aluminum tranny cooler with the stock steel cooler
10 blade stock electric fan in place of the old 5 blade
New heater core (that job was a pita)
used the open cooling system valves for heater lines.

Future
Cut vents in the hood
Flexolite 110 electric fan to replace stock mech fan.
Spal controller for the aux fan
Hesco water pump
Plumb the power steering fluid through the tranny cooler in the 3 core radiator.
Maybe a lower t-stat when the stroker goes in like a 180 degree
All should run cold...

 

[RichP]

Your problem with overheating at hiways speeds is the raised rear hood, that area near the windshiield is a very high pressure area and is forcing air into your engine compartment, this may be nulifying the airflow thru the radiator at hiway speeds by building up too much pressure.. The raised rear hood works great for crawling thoug, wonder if anyone could come up with a elpitical lever setup to raise and lower the rear hood with a lever on each side....
The reason I know this, I added 4 washers to mine, noticed my temp gauge went well above the 210 it normally runs at, both to work and from work, I drive the NE extension of the PA turnpike, downhill in, all uphill back and generally at 80mph in the morning and 70+ 0n the way home.

 

[muduck18]

Your problem with overheating at hiways speeds is the raised rear hood, that area near the windshiield is a very high pressure area and is forcing air into your engine compartment, this may be nulifying the airflow thru the radiator at hiway speeds by building up too much pressure..

X 2
combined with the electric fan your engine is cooking..
but you already knew that part

 

[SCW]

Wow that's overnight. Looks like enough for a week. I can get all my stuff in side with three kids and a wife for a weekend. (The spare is on the roof). That includes spares and tools. Can't see out the back window and the sleeping bags are at the kid's feet.

Matt

That's two adults (one a woman, sheesh), 4 kids and a dog. I could get by with a trailer about 1/2 the size, but that's the only one I've got.

Your problem with overheating at hiways speeds is the raised rear hood, that area near the windshiield is a very high pressure area and is forcing air into your engine compartment, this may be nulifying the airflow thru the radiator at hiway speeds by building up too much pressure..

Interesting, I'll try putting it back down and see what happens. I noticed today that both on the freeway and in traffic shutting down the AC solved the problem withhin a minute or so. I'm not sure why that is, but the AC (in my experiments today) played a huge part of getting hot.

I'm still waiting for the 10" fan that will be going under the new core in the hood, but I'm now second guessing the scoops both on a functional and aesthetic basis. I think flat black expanded metal done correctly will look better on the hood, and work 10x better.

 

[Clint]

I noticed today that both on the freeway and in traffic shutting down the AC solved the problem withhin a minute or so. I'm not sure why that is, but the AC (in my experiments today) played a huge part of getting hot.

Is the clutch allowing it to cycle on and off? We have a ZJ with a toasted clutch that won't shut it off. It gets pretty warm unless you manually cycle it.

 

[5-90]

The AC tends to put extra load on the engine, and the condenser up front leaches heat into the airstream - being in front of the radiator, it will decrease the efficiency of the thing.

I find this idea interesting - and I'd like to hear more trails on it. A couple potential improvements - take this with a grain of salt...

Hood scoops - facing forward. They should allow "ram air" to go over the heater cores, and help with airflow down through the engine bay (you'll end up venting hot air over driveline this way...)
Auxiliary fans - perhaps a couple smallish 12VDC fans set up - probably as "pullers" (mounted under the cores, and drawing air down through them - again, venting underneath...)
Auxiliary fans - mounted as "pushers?" Probably be less efficient than pullers (since they'd be drawing engine bay air upwards through the cores,) but it would probably help with engine bay ventilation overall, so the idea is not without merit...

5-90

 

[SCW]

Is the clutch allowing it to cycle on and off? We have a ZJ with a toasted clutch that won't shut it off. It gets pretty warm unless you manually cycle it.

Not sure- it cycles some when at idle, but I've never seen a car that didn't. Should I test it by reving the engine to about 1500rpm and see if it cycles? How frequently should it cycle?

Hood scoops - facing forward. They should allow "ram air" to go over the heater cores, and help with airflow down through the engine bay (you'll end up venting hot air over driveline this way...)

I thought about that, but it would also let a lot more debris/water/snow into the engine compartment and onto the core. I'm thinking of building a grill/cover out of expanded metal and welding it to the hood. This would be somewhat domed and be for improved flow with good protection. I can't decided if it will look OK or not, the wife has decided not, lol. Her opinion doesn't really mean much when it comes to the Jeep though, lol.

Auxiliary fans - perhaps a couple smallish 12VDC fans set up - probably as "pullers" (mounted under the cores, and drawing air down through them - again, venting underneath...)

I actually looked at computer fans quite a bit, they are 12v and small, but for $30 I got a 10" fan that can be configured push or pull and produce over 1K cfm.

Auxiliary fans - mounted as "pushers?" Probably be less efficient than pullers (since they'd be drawing engine bay air upwards through the cores,) but it would probably help with engine bay ventilation overall, so the idea is not without merit...

You mean in front of the radiator? I don't think there is room (thicknes room, it's pretty thin up there) and I'd prefer not to block what there is, so that would really be a last resort I think. But I've thought of it. My new 10" fan should fit there should I decide to go that route.

Thanks all, it's actually cooled off here a little, I'm actually a little dissapointed because I wanted to see how this worked trailering over 100F, but I'm not complaining!

 

[5-90]

Not sure- it cycles some when at idle, but I've never seen a car that didn't. Should I test it by reving the engine to about 1500rpm and see if it cycles? How frequently should it cycle?

I thought about that, but it would also let a lot more debris/water/snow into the engine compartment and onto the core. I'm thinking of building a grill/cover out of expanded metal and welding it to the hood. This would be somewhat domed and be for improved flow with good protection. I can't decided if it will look OK or not, the wife has decided not, lol. Her opinion doesn't really mean much when it comes to the Jeep though, lol.

I actually looked at computer fans quite a bit, they are 12v and small, but for $30 I got a 10" fan that can be configured push or pull and produce over 1K cfm.

You mean in front of the radiator? I don't think there is room (thicknes room, it's pretty thin up there) and I'd prefer not to block what there is, so that would really be a last resort I think. But I've thought of it. My new 10" fan should fit there should I decide to go that route.

Thanks all, it's actually cooled off here a little, I'm actually a little dissapointed because I wanted to see how this worked trailering over 100F, but I'm not complaining!

OK...
"Pusher" or "puller" fans usually refers to the fan either "pulling" air through the related cooling element, or "pushing" it. Either way, I was thinking about having the fans underneath the hood, under the heater cores.

As I said, the idea does have merit - and I'm mildly surprised I didn't think of it first. Do you have an infrared "non-contact" thermometer? Check the temperatures with the heater cores disconnected from the system, and again with - I'd suggest checking the temperature at the thermostat housing, at the passenger side radiator tank (hot side,) and the driver's side radiator tank (cold side.)

The thermostat housing is probably going to be the best indicator of internal engine temperaure - it's thin aluminum, and it's where the coolant is just exiting the head...

I'd be interested in seeing the results, if you get them.

5-90

 

[Fairmonco]

Exactly how hot does it run at?


BTW,check alllll over your hoses real good.

 

[Lodi Jim]

You have a good configuration set up with the heater core.
xxxpedition did a similar set up with a puller fan, I believe.
His website does not have a write-up, but it has pictures.

 

[SCW]

OK...
"Pusher" or "puller" fans usually refers to the fan either "pulling" air through the related cooling element, or "pushing" it. Either way, I was thinking about having the fans underneath the hood, under the heater cores.

As I said, the idea does have merit - and I'm mildly surprised I didn't think of it first. Do you have an infrared "non-contact" thermometer? Check the temperatures with the heater cores disconnected from the system, and again with - I'd suggest checking the temperature at the thermostat housing, at the passenger side radiator tank (hot side,) and the driver's side radiator tank (cold side.)

We are on the same page regarding the fan, it's going under the core and polarity/blade direction can be changed to run it as either a pusher or puller. I will set it up as a pusher first, then maybe try it as a puller and see which I like better. With the air pressure under the hood at speed pushing the air up and out of the compartment might be best, rather than trying to force it all the way down and out past the block.

I don't have an infrared thermometer, the gauge in the dash will have to be the datum.

Hopefully the fan will get here today so that I can get it finished before I have to head out of town on Friday.