Sorry I didn't take many pictures, but the procedure is relatively simple, with few warnings. No one seems to have written one for 1st gen LS400, so here it is (I imagine it is similar for 2nd gen too):

The job takes about two hours at leisurely pace, which may include an occasional sandwich while you wait for it to drain and such. A cold beer helps too.

Supplies and tools: pliers, 10mm, 12mm, 14mm, 17mm sockets and wrench. Can't remember if 14mm needs to be deep socket... probably. You should have a deep socket set anyway. Get one at harborfreight at least.

1 bottle of Toyota AT fluid.
1 gallon or more of Toyota coolant, or you can reuse old one if good. Do NOT use ANY other coolant or AT fluid. You were warned! Read up, research and buy from the dealer. Not expensive anyway.

Order a replacement radiator. Denso is not OEM and not very good quality so stay away. Many people complained about them lasting less than a year, leaking, and even not having all the parts/hardware on them. Ideally you want OEM (maybe from Amayama), but I installed "Spectra Premium" from RockAuto $90.00 plus shipping. Two year warranty, vs 1 yr for Denso. From what I see, it's all aluminum and it arrived banged up a bit:



The guy who delivered it (Fedex) didn't seem like the most careful guy either. If they had styrofam protection all around, or at least on both top and the bottom, it would be MUCH better. This radiator is SUPER sensitive - the moment you take it out of it's packaging, which was just one box, no double boxing or anything like that, I suggest you find a holy spot for it, and don't even look at it sideways or anything. Make sure no one comes even close to it. I don't know how, but I bent few fins myself - nothing terrible, but all radiators are soft, that's obvious.

The radiator comes with most hardware on it: the screws at the top, which hold the plastic fan shroud are in a baggy (and the screw holes lined up perfectly on one end of the radiator, but on the other, they needed a bit of "convincing" to let the screws in - so not really a 10 for manufacturing accuracy, maybe a 7-8 at best). It will also have few black rubber plugs - those need to stay there, but can easily fall off (I lost one so I reused the old one). Try not to loose them - very easy to do that.

All the hose connections were capped with plastic, one of them was very hard to get off for some reason (had to use pliers and even then, it was hard!)

To remove the old radiator, you could figure it out yourself, but in general, here is a writeup:

1. First of all - let the car cool down! You don't want to be burned by hot coolant.

2. Jack up the front end.

3. Remove the overflow tank cap:


(image courtesy of Lexls)


4. drain the radiator coolant: Open the 17mm screw which is smack in the middle of the engine on the front:


(again from Lexls)

If you forget to open this screw, the coolant will not be draining.

5. Open the drain **** on the bottom, passenger side of the radiator. It is a plastic thing, but cannot be done with fingers, you need pliers. OEM is white, you cannot miss it, most aftermarket are black, harder to see. OEM also has a rubber hose coming out of it, so you can direct the coolant wherever you want. You could probably fit a gallon water bottle under it (about a gallon fits in the radiator), or if not- put it sideways, close the lid, and just cut a little hole in the side for the hose to drain into it. If your coolant is fresh, red, new,you can reuse it.

6. Remove all the plastic intake parts that are on the top of the radiator so you can access the radiator.

7. Loosen these two screws. The picture shows the left one, there is the same bracket on the right. On mine, one is 12mm (right one I think) and the other is 10mm. I think they did that just to screw with us, pun intended.



The radiator sits in its cradle at the bottom, and is held in place by these two screws and brackets.

8. After the coolant is drained, disconnect the two BIG hoses on the top. These are obvious, you can't miss them. You can see one in the top middle of the picture above - it connects at the bottom of the radiaor; the other one is on the driver's side, connects at the top of the radiator. If it is hard to disconnect from the radiator, then disconnect them from the car side, and leave them on the radiator. Important observation: I ordered aftermarket hoses years ago, to replace the ones on my car which are obviously OEM. The OEM were in BETTER shape yesterday, more pliable but also firmer, and I could tell they could take abuse no problem, while aftermarket were stiff like hell and they would probably break. They also did not have the extra sleeve around them like the oem. So I left the oem hoses in place. They look and perform as good as new it seems.

9. Disconnect little hoses, if memory serves me there should be two on the top, connected to the top pipe which runs along the edge of the radiator.

10. Disconnect to small hoses on the bottom of the radiator - those are for AT fluid. You will loose some 1/4 of AT fluid though, so be ready to add some later.

11. Unscrew the plastic fan shroud that is screwed to the top of the radiator. It has plastic tabs, you can't miss it - I think two of them. Mine are broken, I just ordered a new shroud.

12. Now the radiator should be loose and easy to remove. Just pull it up out of its place. NOTE: there are two little protrusions at the bottom of the radiator which sit in their rubber bushings. You should take them off your radiator and transfer them on the new one. In my case, one stayed with the car, one stayed with the radiator, so I was looking where did it go... but you need both, they are rubber and that's what the radiator rests on.

13. Once the radiator is out, transfer some of the parts from it onto the new radiator:
- The new radiator has the plastic drain ****, but no rubber hose like the oem so I took it off the old one and put it on the new one. Perfect fit. Not really unnecessary, but doesn't hurt.
- There is a thermostat at the bottom of the radiator, driver's side. It is white, and may not be easy to access due to suspension parts covering it. So I disconnected it only after I loosened the old radiator. Obviously, you cannot remove the radiator before you disconnect that thermostat. Then, once out, unscrew it (17mm if I remember correctly, it was screwed in with lots of torque) and screw it back into the new one. Fits right in.
- There is a long 1/2 in pipe along the top, number 6 in the picture below (although it also has two brackets not shown in the picture):


- you need to unscrew it from the old one and screw it back into the new one. Uses same screws as the shroud and has a 17mm banjo screw at the very end. I marked with a marker where the holes in the screw are so that when I tightened it, the hole pointed toward the opening. Don't know if that was necessary, but I did it anyway.

14. Now, your new radiator should be ready to install.

15. Put the new radiator in the cradle at the bottom, make sure it sits well (before you do that, it may be a good idea to inspect your drive belt btw - I actually noticed a little longitudinal tear in mine while I was under the car! And also see if there are any screws laying around there, I found one)

16. Put back all the hoses, and screw in the two brackets at the top. one is 10mm the other 12mm screw. You can probably lower the car at this point.

17. Fill up as much as you can through that 17mm plug in the middle - mine fit only a little bit. Pour the rest into the reservoir/overfill tank.

18. Add as much AT fluid as it leaked. Check the level carefully!

19. Start the car, and keep adding the coolant for as long it keeps falling too low. There is no "Burping" this car, you just add coolant, and it runs out if it was not enough.

Hope this helps.

 

Thanks for the detailed writeup, peterls. The rad in my '98 is original so I'll probably have to replace it sooner, than later.

 

burping or bleeding the coolant is very important, so don't just think filling it up is enough.
remember to turn on the heater to add coolant to the core, hold the revs up for a few minutes to kick out the excess air, and add coolant as needed.

more:
http://www.lexls.com/tutorials/cooling/coolant.html

 

Nice writeup.

Since you're removing the ATF hoses going to the ATF cooler at the bottom of the radiator, now is a good time to replace them with new ones. I use by-the-foot generic stuff for applications like this.

Also, to consider, depending on how new your coolant is, if you collect it in a clean container and it is pretty new and uncontaminated, it can be re-used.

Finally, LOLZ, looking through your photos, I'm reminded that I still have my RockAuto box my radiator came in. It is stronger than most boxes and is the right size and shape as a giant tray I use for example to put all the big plastic intake pieces and engine covers in when taking stuff off an engine. Maybe don't recycle that just yet.

 

Thanks for taking the time to create this tutorial, nice job! I'm surprised half the stuff that gets shipped to home actually makes it here in one piece. Amazon rarely uses enough packing. Oldskewel has a great idea about saving the box. I always keep several big pieces of cardboard in the garage so I can throw a piece down on the floor, driveway, or the grass on the side of the drive and reach under the car to do certain things. That way I don't have to jack the car up, put it on stands, and use a creeper. Worked great for waxing the lower panels and bumpers this spring.

 

I use a piece of cardboard folded 4 times when kneeling on the ground. Worked on too many cars over the years on cement and gravel driveways. Knee pads don't work. Can't even kneel on carpet anymore cuz they're so bad.

 

For kneeling ground cover, my solution is those 2'x2' interlocking foam squares, about 1/2" thick, that you can snap together to make padded flooring. But I use as many of them as I need, thrown about under the front, sides, stacked a few deep when kneeling on them, etc. Works great for me. Waterproof, light, cheap.

 

As for burping - there is no traditional burpiing the LS cooling system as far as I know. You just keep adding the coolant as long as it needs it, right?