[cary]

Well after doing Raventai's mods, I came to find out that both my fan clutch and radiator were on their way south. I tried the fan clutch first, but could clearly see when flushing the cooling system that there was sludge in the top of my radiator. My symptoms were the truck heating up to 205-210f on an 85 degree day while driving in town, and starting to get up to 210f on the same day as I would push past 80mph on the freeway.

The fan clutch helped some but when climbing hills, you could see that there was a lack of overall cooling capacity. It simply would start to climb and keep climbing until I stopped at 215f. Now the same test hill, 92f (instead of 85f), resulted in a 200f temperature that was stable.

I used the SUMOTOY instructions for changing the radiator but would add a couple of comments, one specific to swapping the earlier radiator into the 1995-97 trucks.

1) When removing the drivers side bracket from radiator near the frame rails, you go from below!!! I spent 15 minutes trying to do it from above like an idiot. A gear wrench is manditory, you will never get a socket in there or be able to do it with a traditional box wrench.

2) The 1993-1994 bracket is different than the later bracket. It comes with the earlier radiator so when you remove the late aluminium one, you will then have to remove the drivers side bracket that stayed in the truck and replace it with the one that came with the new radiator. Takes about 3 minutes.

3) The new 1993-94 radiator brackets use 12mm bolts to attach to the radiator, the original 1995-97 are 13mm.

4) You will need a 1/4" 12mm deep well socket (6pt), 1/4" swivel and 8" extension to remove/replace the passenger side hidden radiator bolt.

5) By following SUMOTOY's intstructions I did not have to move the condensor, remove any grill pieces or the headlights. All the parts you need to swap the earlier radiator for the later come with the radiator. It is a true bolt in.

6) Total time spent for me was about 2 hours.

Credit to VBCrush for posting the SUMOTOY from another thread. Helped me out quite a bit. Quote:

Hey I've done this 5 times in the last 5 weeks on my 94, 3 times in the field at below zero temps. Here's the short for the 94 (stock with plastic end tanks copper core). When you do this, you will end up with the DS radiator frame in the truck, and the PS radiator frame on the radiator (trust me, it's the fastest way)

- Remove battery and tray (12mm bolts x 8, 10mm battery and ground. maybe 13mm for tray if some previous guy got confused).
- Remove fan from thermo (4x12mm) and shroud from radiator (2x12mm).
- Remove top small hose with pliers
- Remove bottom large hose with pliers
- Remove top large hose with pliers
- Remove two trans line hoses, and snake them up high so they don't leak anymore fluid
- Remove lower bolts near frame (13mm gear wrench) on DS ONLY
- Remove top side bolts from DS ONLY radiator frame (2 x 13mm).
- Remove PS center bushing horizontal bolt thru the front of the grill (12mm - 8in extension with wobbly and 12mm socket while vice grip the bolt on the engine side)
- Remove 12mm long vertical bolt from PS only (you are going to leave the DS frame in the truck and pull the PS frame out with the rad). Move the PS frame toward the rear of the truck, and remove/install.

[Romer]

Nice cary, I'll add it to the FAQ

[Romer]

LX_TREME's thread on his Radiator replacement. Lots of good pics.

http://forum.ih8mud.com/80-series-tech/99029-finally-after-9-years.html

[RavenTai]

Originally Posted by Cary
I measured both to help eliminate the error caused by different people measuring in different ways.

Note the aluminum radiator measurement is first, then the brass/copper.

1 Total depth from front to back of both,
1.35" 1.43"

2 tube spacing
.395" center - center .388 center - center

3. width of the tubes,
.069" .068"

4 number of tubes left to right, and

71 tubes x 2 rows 74 tubes x 3 rows.

Total inches left to right of the heat exchanger itself
27.5" 28.5".

5 spacing of fins center to center up and down,

14.5 fins per inch 14 fins per inch.

Total height of heat exchanger top to bottom
17.5" for both of them.

Notes,
Interestingly, the top and bottom caps look the same for both, the aluminum is just a thinner core. The aluminum radiator is about half the weight of the older 1993-94 radiator. I would guess 20 pounds vs. 35, but my damm bike scale battery was dead so it is a guestimate.

I cannot for the life of me figure out what the early radiator core is. The thing is silver like it is coated, zinc, or something. Pretty shiny.

I would put the fins at being copper, 90% sure. ,

Most when looking at a radiator replacement on their FZJ80 went with the copper brass because it was much cheaper, there had been some ideas that it may also cool better bot no one has compared a brand new aluminum to a brand new brass radiator in service

Also Nobody had ever measured the two OEM radiators, we knew the aluminum had 2 wide rows and the copper fin / brass tube radiator had 3 shallower rows, so we did not know witch was larger, when Cary said he was going to replace his stock aluminum with the brass radiator he provided some measurements.

So from this data we can make some rough estimations of the theoretical effectiveness of the two radiators


these numbers are not perfect, there are radiuses & curves involved that are not taken into account but these are similar on both, also the tube surface area is calculated as if it were a single deep tube not 2 or 3 separate tubes, but we are interested in a relative value between the two not the actual area so this should work,

General Size
Total volume enclosed by the outside dimensions of the two

Aluminum 1.35”x17.5”x27.5”=
650 cubic inches

Copper/brass 1.43”x17.5x28.5=
713 cubic inches

The 93/94 radiator has a larger heat exchanger



Fin surface Area

Aluminum fin
1.35”x.326”=
.4401 square inches
X2 (top and bottom of fin)

.8802 square inches of surface area per fin

Copper fin
1.43”x.32”=
.4576 square inches
X2

.9152 square inches of surface area per fin

Each fin on the 93/94 radiator is larger,




Number of fins

Aluminum
14.5 fins per inch x 17.5 inches =
253.75 fins per column x 71 columns=
18,016. fins

14 fins per inch x 17.5 inches
245 fins per column x 74 columns=
18,130 fins


Total fins surface area

Aluminum
18,016 fins x .8801” per fin=
15,855 square inches of fin surface area

Coper brass
18,130 fins x .9152” per fin =
16,593 square inches of fin surface area


Tube surface area
Aluminum
(1.35”x17.5”x2) + (.069”x17.5x2)=
49.665 square inches per tube x 71 tubes
3,526 square inches of tube surface area

Copper/brass
(1.43x17.5x2) + (.068x17.5x2)=
52.43 square inches per tube x 74 tubes
3,880 square inches of tube surface area


Adding it all up
Aluminum
19,119” or 132 square feet

Copper brass
20,473” 142 square feet

Not a huge difference but enough to make the copper brass unit desirable when you need a new radiator,

Added to this is the cost difference, the brass being cheaper.

Another is that copper conducts almost twice as much heat as aluminum

Thermal Properties of Materials - Conductivity, W/cm-K
Silver 4.173
Copper 3.937
Gold 2.913
Aluminum 2.165
Tungsten 1.969
Beryllium 1.772
Magnesium 1.575
Molybdenum 1.299
Brass 1.220
Beryllium-
copper 1.063
Zinc 1.024
Nickel .906
Platinum .734
Iron .669
Steel .669
Tin .630
Lead .343
CRSS -410 .240
Monel .197
Titanium .157
CRSS -321 .146

The only down sides to the copper/brass radiator is that you need to have a coolant that provides protection for brass, both Toyota red and older style American coolants provice thir protection, soem of the newer coolants do not.

also the brass radiator is heavier and that is why race cars and production cars have gone to aluminum, pound for pound you can make a much larger radiator out of aluminum but here where they are the same size (the brass actually being slightly larger) copper brass is the way to go. these few pounds will not effect any thing in the real world on an 80 series

[turbocruiser]

Wow RT, what a great post, I wont quote it cause its so long, but what a great post. Thanks for taking the time and trouble to think that through.

[Rich]

During past web research I have on several occasions come across information stating that the heat transfer capability of aluminum is superior to that of solder coated copper.

I think that determining which of two specific Toyota radiators has the better heat transfer capability goes beyond calculating volume and square inches of tube & fin area.

http://www.eng-tips.com/viewthread.cfm?qid=61247&page=9 is one link I saved quite a while back. Interesting discussion that covers some of the factors involved comparing aluminum to copper radiators.

[RavenTai]

I see a lot of talk in that thread about watts per pound and watts per dollar, recyclign problems of solder and how the new brazed radiators compare in those aspects but not much about watts per size witch is what we are looking at with these two as the size is fixed. what was there says copper is better.

I would agree that there is much more to it than just surface area but that is one of the major measurements of a heat exchanger,

I do not have the thermal conductance of solder though it will be less than any of the other materials in question, and it will be different depending on alloy used nor do I have the dimensions of the solder joint but by eye I do not think the solder is a hindrance, the way the fin is soldered to the tube there is a much wider contact patch than the cross section of the fin, I think the fin would then be the bottle neck making its conductance important, not the solder, but would need to do the math to say with any certainty

[IdahoDoug]

The surface area of the copper rad that has solder on it would be quite limited, and even if it were very liberal the nearly double thermal transfer rate of copper would have the older radiator overwhelmingly superior ceteris parubis (sp - means "all else equal").

RT - very nice post! Happy I replaced my 97's with a brand new brass one from the Dan Man...

DougM

[Rich]

The solder on the copper tubes is where it matters the most, between the tubes and the fins. It is the fins that account for the majority of the cooling capability, and the interface between the tubes and fins appears to be very significant.

I'm not able to say which of the Toyota land cruiser radiators works best, but am pointing out that the factors go beyond the thermal conductivity of pure copper and the thermal conductivity of pure aluminum.

[IdahoDoug]

I'm with you. I see that you're saying the flow of heat is interrupted at junctions where solder is used and the heat transfer between the joined parts is at the mercy of the amount of physical connection. If fit is poor the heat transfer would depend upon only the solder to transfer heat from one to the other. Agree. Would expect this to again be a minor factor but worth pointing out, ya detail freak!! Heh.......

DougM

[Romer]

Man, thats great stuff Raventai. My criteria for the brass radiator was Cdan and Slee both said it would work just as well and it saved me $300 from the local delare (with TLCA discount) A Radiator was not something I could wait to have shipped from my good friend Cdan as the existing one was busted.

For those who don't recall : When climbing in the engine compartment to replace Spark Plug #6, do not put your hand or apply any weight near the top part of the radiator. The little plastic fitting will SNAP with just a little weight added making the Radiator useless.

[crosswire]

Originally Posted by Romer

For those who don't recall : When climbing in the engine compartment to replace Spark Plug #6, do not put your hand or apply any weight near the top part of the radiator. The little plastic fitting will SNAP with just a little weight added making the Radiator useless.

I did that - what a pain that was! Just ended up using JB weld - has worked a ok for about 3 months now.

[medtro]

Originally Posted by RavenTai

Most when looking at a radiator replacement on their FZJ80 went with the copper brass because it was much cheaper, there had been some ideas that it may also cool better bot no one has compared a brand new aluminum to a brand new brass radiator in service

Also Nobody had ever measured the two OEM radiators, we knew the aluminum had 2 wide rows and the copper fin / brass tube radiator had 3 shallower rows, so we did not know witch was larger, when Cary said he was going to replace his stock aluminum with the brass radiator he provided some measurements.

I was just reading the Cooling System information for the 1FZ-FE engine. In the radiator section. it says "The aluminum radiator core is used for weight reduction."

[jsmith8918]

I finished my radiator replacement tonight. This job took a bit longer than I expected, even after reading all the posts I could find. My main problem came when I tried to removed the fan clutch from the four studs and pulley. I ended up using two pry bars and a hammer and cold chisel to break the bond that had been created over the last 150K miles. I replaced the original fan clutch with a new blue hub one from cdan (many thanks) and did the blue hub fan clutch mod first. And then getting that thing back on was fun, too, as the nuts had to be pretty well on before they would bite on the stud threads. Strange nut design? (Only after I was completely done did I realize I had bought four brand new nuts from CDAN along with all the other stuff.) I did remove the grill (piece of cake), but left the headlights in place which made it a bit tricky getting those two nuts off by the headlights. I also saw no reason to remove the condenser so I left that in place, too. (Mine is a '97 LX450.) I hope this job is worth another 150K miles because it will take me that long before I'm ready to tackle it again.

[Mr. Toad]

Originally Posted by cary

. . .
3) The new 1993-94 radiator brackets use 12mm bolts to attach to the radiator, the original 1995-97 are 13mm.

. . .

Toyota used a 13mm hex-head?!?

[cary]

Originally Posted by Mr. Toad

Toyota used a 13mm hex-head?!?

Yep.

[sparkplug]

First I wanted to say thanks to Cary and SUMOTOY the information was VERY helpful. What I found was that if you have a 95-97 FZJ-80 and are going to go with the 3 core offered from 93-94 you can do it a slightly different way with less tools. (I don't have many)

After removing the battery box, clutch fan, fan shroud, and hoses you can just unbolt the radiator from the mounting brackets. Just remove the top side bolts, middle side nuts and bottom bolts and you can slide the radiator right out. This allows you to access the bolts in the middle of the radiator with the rubber bushings and hidden nuts. Now you can use a simple wrench and vice grips to easily remove them. After you have removed the new 3 core brackets from the radiator install them by just the center bolt with the rubber bushings. These are the only ones you cannot access when you install the radiator. Next put one nut on each middle bracket stud to keep the brackets vertical. then it is a good idea to have another set of hands. Have one person slightly bend one of the brackets away from the center of the engine bay(it will move pretty easy because it will flex with the rubber bushings on the sides and the ones on the bottom that you never touched). You need to get the radiator down in the truck and insert one side at a time. I was able to do it without forcing or damaging the radiator.

[jmvar]

I just did a flush of the cooling system 3 months ago, now I have a leaky radiator so I have a new one waiting to go in.

Should I plan on replacing all of the coolant or will some of it stay in the block? I guess my question really is should I bend over and spend the $50 in coolant at my local dealer?

[Beowulf]

You need to replace all of the old coolant with fresh coolant.
-B-

[tblume]

do a search for "brass block drain" or similar, it's DS just aft of shock mount, middle of the engine; you should get ~90% of your coolant out of the block this way, and blowing air thru the system from the top heater hose will push out most of the rest.

[zx9r]

Originally Posted by cary

I used the SUMOTOY instructions for changing the radiator but would add a couple of comments, one specific to swapping the earlier radiator into the 1995-97 trucks.

OK, I give up. Searched for 30 minutes last night and another hour today...can't find this famous SUMOTOY tutorial on radiator replacement. Although I don't expect it to be too complicated, I don't want to miss any hints that might save time/aggravation before I get started...Can someone direct me to the thread or better search terms?

Cheers