Radiators

[macgyvr]

Pretty much as long as I've been around NAXJA there has been a 'deal' with 1800radiators on a three core for 100 bucks. Do I just drop NAXJAs name? Do I mention that it was set up by Dirk? i think, does this deal exist? And those that has these radiators, are they making a difference and holding up well?

mac 'wasn't sure whether to oem tech or mod tech this' gyvr

[Eagle]

The deal has been on-going for quite some time. Although it was originally set up by Dirk, more recently I believe the names to drop are Damon and Yogi ... both of whom are (or were) with the radiator company. The price was $99 originally and the most recent post I remember said it was up to $106 IIRC.

It's a GDI 3-core. Although I bought mine locally before this deal was set up, I have had a GDI in the '88 for 3-1/2 years and it's still running cooler than the OEM radiator ever ran.

[rockwerks]

yogi adn naxja special on gdi 3 pass still 99.00 as per Yogi's email last week

[1986xj]

Anyone know if they make one for my 86 V6 and will the thicker radiator still allow room for the A/C condensor? Mine has some age on it and if I end up replacing it I'd like to "upgrade" at that time.
Mike B.

[Backdraft]

CRAP.....I guess not thinking got me again. I just ordered a new GDI 3 row about a two months ago and didnt mention anything about NAXJA or the guys names. Price on mine was $150. Hit my door the next morning after ordering it. Keep this in mind unless you dont mind paying 150 for one.

Brainlapsed Mike:mad:

[Judd W. VA]

Is another case "of you get what you pay for" with the GDI radiators too. The one i got for my '98 (paid $100), to upgrade from a single core OEM aluminum, did seem to cool better at speed. At low speed it did not though...this is something to keep in mind. It always seemed to seep coolant also. Trying to prepare my Jeep to be 'dependible' so i can head away to school i could not trust it with this problem. Spent the few bucks and got an OEM twin core aluminum. The quality is supurb. Fit was perfect. I also found it does cool better than that GDI at all speeds, esp slow where is way better, and i am sure this radiator will be totally dependible.

In other words, if you want a trouble free very good capacity rad, the UC radiator will do the trick- just another angle.

[Eagle]

Originally posted by Judd W. VA
Is another case "of you get what you pay for" with the GDI radiators too. The one i got for my '98 (paid $100), to upgrade from a single core OEM aluminum, did seem to cool better at speed. At low speed it did not though...this is something to keep in mind. It always seemed to seep coolant also. Trying to prepare my Jeep to be 'dependible' so i can head away to school i could not trust it with this problem. Spent the few bucks and got an OEM twin core aluminum. The quality is supurb. Fit was perfect. I also found it does cool better than that GDI at all speeds, esp slow where is way better, and i am sure this radiator will be totally dependible.

In other words, if you want a trouble free very good capacity rad, the UC radiator will do the trick- just another angle.

Judd --

I'm glad your XJ is cooling okay and I don't like to pee in anyone's corn flakes, but there is no such thing as an "Up Country" radiator. The Up Country model gets the same radiator as any other XJ with a/c and/or tow package. It's an aluminum core with plastic tanks, and it does not cool any better than a GDI. If for some reason your GDI wasn't cooling at slower speeds, I would suspect either a fan clutch problem, or sludge clogging the tubes.

[rockwerks]

I'm glad your XJ is cooling okay and I don't like to pee in anyone's corn flakes, but there is no such thing as an "Up Country" radiator. The Up Country model gets the same radiator as any other XJ with a/c and/or tow package. It's an aluminum core with plastic tanks, and it does not cool any better than a GDI. If for some reason your GDI wasn't cooling at slower speeds, I would suspect either a fan clutch problem, or sludge clogging the tubes.

Lets jsut hope your system is in perfect condition because eh alum and plastic rads are very prone to bloww of teh plastic end caps under high pressuer...mine blew apart when teh rad cap failed to open....the entire seam on the drivers side split open...teh coolant emptied in less than 30 seconds....I wil never use one again...give me the metal ones!...my local rad shop pressure tests everything @ 30 psi except for these because the plastic flexes enough to slip out of teh retaining crimps....not a pretty site

[Judd W. VA]

Eagle, oh Eagle..... Thought i'd hear from you on this!! There was not a thing clogging the core. The system is spick and span i assure you. Is once again the aluminum vs brass/copper/lead contruction as well as the denseness of the fin principles involved here. I noticed LESS low speed cooling from the three core GDI after installation than from the SINGLE CORE aluminum previous. I know this for a fact. I saw it with my automotive experienced eyes. Is a very common known delemma that happens when adding layer after layer of cores....you create more restriction to airflow. The fins and core design of this aluminum is more open to airflow than was that fairly nasty core of that cheapo GDI. Is a know fact that some rads cool better than others just due to fin design, and is the case this time in my view...as well as with the use of aluminum.

I also happen to LIKE plastic tank radiators. I do not see them going bad any more often than non. Is just a different kind of failure, and more sudden usually.

There IS a specific UC radiator. This radiator would NOT have come with a 'towing package' because mine is a 5-spd. There was no 'towing package' for use with this trans. This rad has no trans cooler so could only come on Up Country 5-spds, or maybe those with an 'A/C and extra cooling' package, if there was such a thing. In this case you were not really correct.... My '98 has factory A/C and a single core alum radiator.

The bottom line is that all around this OEM two core aluminum does a better job keeping my XJ cool here in mega hot Utah than my GDI would have. Not to hardly ever need the elec fan using A/C and in this stupid stop and go traffic here i think is amazing.

[rockwerks]

My '98 has factory A/C and a single core alum radiator.


Im sorry to here that make sure your cooling system stays in perfect condition and reaplace your cap yearly.....if the system overheats and cant vent this plastic and alum rad of yours will burst before a hose does

[RichP]

Oh man, not ANOTHER bleeding heart Nauga lover, sheesh it's bad enough putting up with the bambi lovers. There is nothing I look forward to more than the fall nauga season, we tie it in with nite racoon hunting season. We also found that spotted owls make excellent nauga bait.... :D

[chadc]

I am running the gdi, and compared to the factory 95 5spd radiator it made a world of difference. The first one I got was all beat to hell, probably ups. I called 1800radiator and they shipped another one to me next day. I like the gdi . as far as aluminum I would prefer it, but not with plastic.

[Eagle]

Judd is correct that radiator design has to be considered. On a direct comparison of like quantities of metal (however they measure these things), copper is a better conductor of both heat and electricity than aluminum. Period. That having been said, there is no question that an aluminum radiator can be designed to cool as well as a copper one -- albeit with the necessity of larger radiating area (more and/or bigger fins, and more tube surface area).

I'm with XJnation on tanks -- don't like plastic tanks, don't trust plastic tanks, don't want 'em in my trucks.

[Judd W. VA]

Hey, i was not easy to convince of the viability of plastic tank radiators but have seen them last for so long and work so well that i am no longer scared of them. I have even been able to repair them successfully. I would never pressurize any radiator to 30 psi, i don't care how good that rad shop is. My Snap-On rad tester redlines at 20 psi. In all my years i have never seen a radiator honestly blow because of the rad cap sticking.....

As i remained convinced as before, is not the conductivity of copper/brass over aluminum but the construction of each. The lead in the copper/brass rad helps to reduce it's efficiency. Aluminum rads are composed of only aluminum.

I come to conclusions of most things in life from personal experiences, not from what other's may say. I have seen this OEM aluminum outperform the three core GDI in both cooling ability, fitability, and certanly durability, so that is where i am coming from on this.

[rockwerks]

In all my years i have never seen a radiator honestly blow because of the rad cap sticking.....


Ive seen it three times in cherokees.....once to me in Seligman AZ two years ago in my 88 XJ, once on terminator last year a 94 I believe and teh other was to stop and help a guy from Calif on I40 about 1/2 mile from my house a month ago....I had several rads @ home so we put one in....a GDI by the way..and if I go to the salvage yard and look I bet 60% of teh composite adn alum rads are leaking @ the ends

[vintagespeed]

I need a new rad. now and was wondering how the Modine 2 row cooled compared to the GDI. I like the idea of 2 larger rows than 3 small ones cause my '89 has lots of crap in the system. The new rad will benefit from a coolant filter, but I still wonder if the Modine is better? It's NOT an aluminum trail-stranding time bomb BTW, they're all metal.

[PNWXJ]

I am too looking for a new radiator. Any one else not pleased with their GDI 3 core? I have never heard anything bad only good. Could it be there was some blockage from manufacturing?

Tim

[Bones]

I am too looking for a new radiator. Any one else not pleased with their GDI 3 core? I have never heard anything bad only good. Could it be there was some blockage from manufacturing?

I have TWO GDI three core's setting in storage and ONE Modine two core cooling my 4.6L stroker.

IMHO GDI is crap. In three GDI's I have had shipped to me two were damaged PRIOR to boxing. One was severe enough to require replacement of which I ended up paying the shipping on :mad: .

GDI: 3x 0.25 cores (.75" total)
Modine: 2x 0.625" cores (1.25" total)

Go Modine or go home Mac :D

Bones :skull1:
NAXJA #6

BTW: If you are still wanting to throw your money away I would be willing to part with a core checked (<5% blockage which is VERY good for a GDI) GDI 3-core rad for $75 + S&H. I also have one with a moderate half moon of bent fins from a motor mount incident that I would take $25 plus S&H on. It didn't leak when pulled and it cooled my stock 4.0 ok I just "upgraded" to a new one with the stroker (then replaced it with the Modine). The cheaper one also was the first of the factory damaged units I received and has some rad cap issues that require a good quality cap.
Both are AT versions for the open systems.

[KarmirXJ]

Originally posted by Bones
I have TWO GDI three core's setting in storage and ONE Modine two core cooling my 4.6L stroker.

IMHO GDI is crap. In three GDI's I have had shipped to me two were damaged PRIOR to boxing. One was severe enough to require replacement of which I ended up paying the shipping on :mad: .

GDI: 3x 0.25 cores (.75" total)
Modine: 2x 0.625" cores (1.25" total)

Go Modine or go home Mac :D



I Agree, GDI is absalute crap! they are the worst mad radiators that i have seen in my entire life. first GDI 3 core i got had a bunch of gunk stuck in it that I couldnt flush out, returned and got another one, 2nd one had totally rusted all the studs for the brackets, all they did was just spray paint the threaded studs which didnt really help at all:rolleyes: crap, i repeat crap.

[KarmirXJ]

BTW: after waisting 2 GDI radiators:rolleyes: I decided to go with VALEO made radiators. their quaility in their radiators beat any made radiator ive seen so far, that includes BECOOL and OEM spec rads, hands down. VALEO gets my vote:D

[RichP]

Just checked out http://www.carradiator.com intersting search engine. Was looking for info on valeo, never heard of them before. Guess as my wife says I'm just too 'whitebread' and have pretty much always stuck with modine :D

[RichP]

Very interesting article http://www.radiator.com/article.cfm?art=alumrads2
Never new that a bad ground could hose a cooling system.

[macgyvr]

well i thought i was going to order a GDI..... now i dont know

where can i get and how much is the 2 core Modine?

mac 'got to keep the bitch cool' gyvr

[Eagle]

Originally posted by Bones
GDI: 3x 0.25 cores (.75" total)
Modine: 2x 0.625" cores (1.25" total)

It's not that simple.

What counts is surface area, both tube surface and fin surface. You want tube surface to transfer heat from the coolant into the metal of the radiator, and you want fin surface to transfer that heat to the air passing throu the radiator.

The XJ radiator has to fit the vehicle, which means a Modine can't be any higher than a GDI. If the Modine tubes are that much larger in diameter, that means it has to have a LOT fewer tubes vertically. So what we don't know is the actual surface area of each radiator. Then factor in that aluminum doesn't conduct (or radiate) as efficiently as copper, and I have to wonder just how much more cooling (if any) the Modine really delivers. To be sure, with big pipes like that it won't plug up as quickly, but copper radiators don't corrode as quickly as aluminum anyway, so I'm not convinced that's all that much of an advantage either.

Modine makes a quality product, and they are (or were in '88) the OEM supplier, but I'm not convinced that a Modine replacement is worth twice the cost of a GDI.

[Judd W. VA]

You are so full of yourself it amazes me. How does your head fit through doors, if you don't mind me saying?! You talk as though you have been in the mechanic/tech world your whole life!! I hate to bring this up in this forum, but i think there needs to be a little 'redirection' and accommodation of other's views and opinions sometimes. You need to listen to other views with a little more reguard. There are some who do know more about automotive things than you do!! As for me, i have been associated with vehicles the bulk of my 46 year life in a professional way and i have formed views and gained experience the whole time. I also have an electical engineering degree and am in the process of complimenting that with Automotive Engineering at present. Perhaps some restraint sometimes??

I have done research in core designs of radiators. Two wide cores provide less resistance than three narrow ones. Is easier to make wide cores in aluminum radiators. Also, if the copper/ brass rads were so great how come the best radiators aren't made of that?! You have gone in this direction again after two years of silence so i will pick it up on this end again too!!

[Eagle]

Judd --

What is it that I seem to have done to pee in your corn flakes all of a sudden? This is a DISCUSSION forum. By definition, that means it is a venue for people to exchange views, ideas, and ... yes ... opinions. You're 46 years old? Congratulations. I've had my driver's license longer than that, and while autmobiles are not my profession, they have been my avocation for longer than you've been on the planet. That may not make me an "expert," but I do think it qualifies me to have an opinion, and to express it. You are free to disagree and to state your opinion.

I don't understand your comment about two years of silence. The GDI radiators have been a subject of recurring discussion on these forums for years. I've had mine in since late 1999 and have often posted how satisfied I am with it. To what silence are you referring?

What's the basis for your statement that the "best" radiators are made of aluminum? The fact that OEM rads are aluminum doesn't mean they're necessarily "better" -- only that they are cheaper and/or lighter and thus more advatageous to the manufacturers. Race cars? Aluminum radiators are lighter, plus the big names can afford a new radiator for every race so longevity isn't an issue for them.

I admit to being old fashioned and conservative. The copper and brass radiators in my Hudsons and AMC vehicles routinely lasted 15 to 20 years. The OEM aluminum and plastic radiator in my '88 XJ lasted 9. I replaced it with a GDI, and with a factory 195 degree thermostat the Jeep runs cooler than it ever did with the OEM heavy-duty radiator. Which would you say is "better"?

[BrettM]

I'm happy with my GDI, and I had one in the XJ I used to have and I know the guy that bought it and it's still doing great.

[rockwerks]

What is it that I seem to have done to pee in your corn flakes all of a sudden? This is a DISCUSSION forum. By definition, that means it is a venue for people to exchange views, ideas, and ... yes ... opinions. You're 46 years old? :rtm:

funny........

as far as flow rates...teh slower teh coolant travels through the radiator the more therms reamoved...that is why they go to a three pass in the same area...to restrict the flow by decreasing the passage size this helps in two ways......more coolant touches the passage sides and the coolant travels slower through the radiator...which in turn cools the coolant more effeciently...

big head......:roflmao:


funny........LOL

[Ed A. Stevens]

Originally posted by xjnation

as far as flow rates...teh slower teh coolant travels through the radiator the more therms reamoved...that is why they go to a three pass in the same area...to restrict the flow by decreasing the passage size this helps in two ways......more coolant touches the passage sides and the coolant travels slower through the radiator...which in turn cools the coolant more effeciently...



You two can keep the battle between yourselves, although the "facts" need to be tempered with the reality of an XJ radiator. The radiator space constraints force a radiator size that compromises the performance (and impacts what improvement work).


The XJ AMC six radiator tubes are long (due to the wide aspect ratio that the space allows). They are too long for efficient cooling, in that the temperature difference of coolant to air at the end of the tubes does not provide much motive to transfer heat. The last few inches of radiator tube length provide very little coolant to radiator conduction heat transfer.

How can the radiator performance be improved?

Cut it to be a more narrow profile (remove the inefficient tube length)? No, that hurts the air side heat transfer (radiator to air conduction).

Slow the coolant down (the effect of small tubes mentioned, or slow speed power pulleys)? No, the coolant is already sub-cooled due to tube length, slowing coolant flow down more increases the unneeded sub-cooling effect (it makes the radiator less efficient).

Speed up the coolant flow (the effect of larger radiator tubes, or high flow pumps)? Yes (maybe), because the coolant dwell time in the overlong radiator tube is less, resulting in a higher coolant to radiator tube metal temperature difference at the tube outlet. The "maybe" comes in with not knowing if the coolant in the tube is turbulant enough to mix hot fluid out to the tube wall? It may help, but interior tube surface finish may restrict an effective solution.

Make the radiator core thicker (more coolant to tube, and tube to air, conduction heat transfer)? Yes (maybe), if the air side heat transfer method can be matched to reject the heat. The airflow limitation is the static pressure capability of the fan system, to draw the air through a more restrictve radiator core. The small diameter XJ fan limits this air pressure performance factor, and limits the effectiveness of the radiator's air conduction heat transfer performance. A deeper fan blade pitch may overcome the airflow problem (something the factory may have rejected due to noise concerns, but we could live with as enthusiasts). Anyone find a deeper pitch mechanical fan blade?

I hope this line of rational helps motivate the greater NAXJA membership to seek a valid solution (lord knows XJ cooling systems can use improvement).



BTW, anyone have an over the shoulder view smiley ;) with a dotted line going to a bowl of corn flakes?

[Judd W. VA]

To all in NAXJA-

I want to apologize to all who were exposed to my ranting and raving without reguard to Eagle's feelings in this thread last evening. I was out of place and will bite my tongue (and key fingers) if i again feel the urge. Dang i was acting more like a Jeeps Unlimited contributor!!

I do tend to have very strong views based in real-world personal experiences and obviously think strongly of them. Perhaps more resraint should be in order with these views of mine in the future.

So sorry,

Judd Wymer

[yellowxj]

I was worried for a while. It was like mom and dad fighting in the kitchen. Glad you guys can disagree(with passion) and communicate/debate effectively and not resort to the kind of lowbrow retorts and comebacks I've seen else where. This is why this is the best forum I've seen for xj tech. (Modine, full switch on the elec, new fan clutch, and a new waterpump solved my problems) :)

[Judd W. VA]

I am damn glad you got your Jeep straightened out.... and for acknowledging my 'testimonial'. I do continue to feel and think badly for what i did Is all i will say on that-

[macgyvr]

geez, and all i asked was about the GDIs lol, all this time all i have ever read is good stuff about them.... didnt know there was so much other info out there, i'm still reading and learning...


mac 'eagle and ed are my heros' gyvr

[vintagespeed]

Now I've been told by reliable sources that the Modine was all metal which is why I'm planning on getting one. Can anyone that has one define it? IS it aluminum, IS it all metal?

[XJEEPER]

Bones, give me the Modine part number now!! Moab Jeff is crying about cooling and needs a hook up.

[Eagle]

Originally posted by macgyvr
mac 'eagle and ed are my heros' gyvr

Hee hee --

Ed and MaXJohnson are my heroes. :D

[Bones]

XJEEPER: Bones, give me the Modine part number now!! Moab Jeff is crying about cooling and needs a hook up.

Would if I could but this mod was one of those low tech ones. The Rad shop ordered out of the book. No fancy rework just what Modine listed.

vintagespeed: Now I've been told by reliable sources that the Modine was all metal which is why I'm planning on getting one. Can anyone that has one define it? IS it aluminum, IS it all metal?

Don't know about all of them but mine is not Alum. It is brass/copper.

As for the 2 vs. 3 row debate both points are valid and I really don't know which is best on paper, but I do know GDI workmanship leaves a lot to be desired. Get a good build and you should be ok, but more of them seem to be crappy welds/solders causing several clogged tubes.
The Modine was far better quality and not that much more $.
Just my $0.02

Bones :skull1:
NAXJA #6

[themud]

I just have to chime in on this one as I am looking at cooling options as well not that I have a lot of problems with it but when its 117* outside and the heep already runs at 210-220* you start looking around...Judd I have to agree with you on the low speed cooling of OEM radiators they just work better I noticed an increase in around town temps when going from stock one core to modine 2 core...

The modine is actually a good rad(I got the two row one) and I have no dislikes about it, after doing some research asking around(race car builders and jeep mechanics)... I like Ed have come to the conclusion that its not the rad but the airflow that is killing us and have been looking at options...In summits catlog they have flex fans for serp belt vehicles but the smallest they have is 16" and our shrouds are only 15" maybe I gonna grab a spare and start hacking to see if I can get a 16" to fit...My only concern is will it hit the hood underside?

I have tried all over to find the factory cfm #s for the mech fan but no one out there has any idea and everyone Ive tried says sure it has to be out there but doesnt know where I even tried the dc help line for stealerships!!!!(They werent any help)....If anyone happens to have the specs for fan to hood clearence just let me know that way if theres no room to start with I wont waste any money!!!

The only other concern I have is will the flex fan pull any more air and at what cost to the power side(not that Im too worried about that 200 hp dont do crap on a rock wall at 3mph, but on the freeway turning 75 how much power will I lose and can people deal with that...My goal is to see if I can redesign the cooling system so that the jeep can keep itself cool at idle without using the aux fan....

Likes, dislikes, ideas all are welcome!!
themud

[Eagle]

On the highway you won't lose any power with a flex fan. The flex fan was an OEM alternative (not on the XJ, but on many cars) rather than using a viscous clutch. All my Javelins and AMXs came with an aluminum spacer (1.5" to 2" thick) and a flex fan. The whole point of a flex fan is that at low speeds it has a deep "bite" to move lots of air, but at high speed the air resistance flattens the blades. I ran the stock fan setup even in the race machines -- it was good to over 6000 RPM and I never felt I was giving up any power.

I've been advised, however, that flex fans are not good for fording water. One version was that the fan blades get bent when the hit the water. That's bad enough, but the other report was that the fan blades screw themselves forward in water until they take out the radiator. I'd guess a flex fan would be fine for Moab, but not the recommended setup for terrain involving water crossing.

[xj92]

Back to radiators. I followed this thread before but didn't think twice about it. I bought a 2-core radiator 3 years ago that's been great but I didn't have a clue what kind it was. I was in a wreck a few days ago and ruined the radiator, so I called the place I bought it and it turns out it was a Modine. So, I want to get another one. The last one cost me $220. Anybody know where to get a good deal on one or if that's a decent price?

[Static-XJ]

Originally posted by Judd W. VA
In all my years i have never seen a radiator honestly blow because of the rad cap sticking.....
Know this was a few pages ago, but I was behind the wheel when a plastic tank split down the side due to overheating. Rad cap never let go. All the coolant went up in a puff of steam. Roughly 8" melted gash in the plastic. Happened in a Mazda Protege.

[Judd W. VA]

This still does not mean the cap stuck!! To me it indicates the probablility that the tank just couldn't take the normal working pressure any longer. To be sure, you would have had to test the cap. Not a big deal with a system tester-

Is not out of the ordinary for me not to go with the general consensus on things, and my preference of alum/plastic rads still stands. Overall in my experience they outperform others...all except the mega-buck all aluminum Be Kools and the such.