Ultimate overheating solution.

After 50 miles of tight, hilly, rocky , slow, fast Western Pa. riding, my 2000 E never came close to overheating for the first time ever. The solution? Took the whole cooling system off my 2001 S, including the fan, and put it on the E. Before you tell me about the jetting and the water wetter and all the other fixes,,,, I did them all, and so has my buddy on his E and he had trouble yesterday and I didn't. Suzuki should have done this from the factory, and hopefully they will in the future. Will have 2 E rads for sale soon. The two systems are VERY different.

I did not really think you would go to all that trouble. You should be getting R & D pay from Suzuki. Good job. Thanks man.

The 2002 DRZ400E has a different right side radiator with two outlets at the bottom. It eliminates the expensive and fragile Y hose but probably also flows better. I'll bet that is a Suzuki's way of addressing two of their problems of overheating and that crappy Y hose. No mention of the improvements in their new model checklist unless I just missed it.

If I had a busted right radiator on my DRz400E I would get the 2002 right radiator which for all I know might be the same as the older S radiator. The 2002 hoses appear to be something one could match up at an auto store. I like that.

I have been lucky and have no boil over problems but would go to the newer radiator if I had to buy one anyway.

Thanks again and you will not have a hard time selling those old z rads.

Are the S rads taller, Thicker, Wider, More fins or rows??? Or is it just different hose routing?

Not many people are in a position to perform that kind of test. Good job and thanks for posting. I riding bud just picked up a 2002 400E and the right radiator is a little different and it has the insulated hose.I am a HVAC mech. and I think a 1/2 inch copper tee will be going in my back pack along with some hose. I already carry some extra clamps on the existing hose on the bike.

As far as temporary overheating solutions go think about this. In the summer when I have high head pressure problems on a AC system I get out the the portable weed sprayer filled with water and spray down the condenser (same as radiator) the pressure drops instantly. It just improves the heat transfer rate incredably fast. So maybe I will buy a small spray bottle or swipe the one form the old ladys purse and throw it in my pack also. You could fill it from your water bottle or a mudd puddle if you have to since you are only going to mist the outside of the radiator while it is running so the water inside is circulating. Hopefully by then you are in the open where you can ride and get a little air moving through it. With winter upon us it may be a while before I test this idea.

Well, I'll just run right out and buy a new set of new "S" radiators and cooling fan :) . I think a small cooling fan would help some.

My bike never boils UNLESS I ride very, very, very slowly or let it idle(like while putting up trail arrows).

I tried Engine Ice....... it's about the same as antifreeeze as far a I'm concerned......it jsut costs more ;(

Straight water is the best coolant ever made, but it's got it's drawbacks of course.

The size and fins of the rads appear to be the same, but the big difference is in the outlet pipes. They are almost twice as big on the S, and the hoses are naturally bigger also. The goose neck out of the E goes straight up to the rad and the S comes out the side and goes into the bottom of the rad. And of course the fan had to make a big difference too. Wether it was the biggest factor or not, I can't tell.

The best coolant would probably be liquid mercury. It is a little heavy though. :)

I just pop a couple ice-cubes into the rad every 10 minutes or so when doing slow trails.

Works like a champ. :)

Ultimate heating solution.

Getting colder here anybody got a 400E motor for my 400S rads :)


[ November 26, 2001: Message edited by: dendrz ]

PSJ55 thanks for the feedback on radiator size. Maybe next ride you can disconnest the fan and see if you are back into boiling over.

If the S hoses are so much bigger how do they fit up to the E outlets? Is the S water pump also bigger? Is the S thermostat in place? I heard the S models also overheat and the thermostat was an obstruction. Heard the same for KTM bikes.What do you think about that? Has your stat been removed? Are you using the S radiator cap? Is it the same as the E cap?

I figgure since you have done all the work on this test I may as well ask lots of questions so we may all benefit from your experiment.

Victor, The outlets on the E are the same size as the S, but the hoses step down to a smaller size to fit the E rad outlets. I left the thermostat in the S and did without in the E. Am running the S radiator cap and don't really know if they are different. I would bet that the water pumps are the same since they seem to have the same covers. I did leave the fan off a few times on Sunday and it showed no signs of overheating. I might even take one of the sensors out of the top of one of the S rads, which aren't hooked up on the E, and try to get some kind of temperature gauge set up to see what kinds of temps I get on a typical ride. That will be just for R & D and not a permanent thing. Will keep you posted on further developments. In the meantime I'm cleaning and checking my E rads and will put them up for sale soon. Pete

Jetting has a lot to do with overheating. Early on when folks were removing the airbox lid and not rejetting overheating complaints were pretty common. I have never had a problem with my 2000 DRZ400E overheating even on some real steep slow technical hills hauling my 240lbs plus gear. I suppose it could happen on very long hills or in mud but I have had no problems. Going one bigger on the main and/or raising the needle might solve some overheating problems without having to buy a new radiator. Just my two cents.


Perry, Whatever works for you. I did call this the "Ultimate" solution. Like I said,,, I tried all the other fixes and nothing really worked. Pete

Like Drbillz said, pure water does work best. I have not had trouble on my S, but I have solved trouble on a car by using distilled water with "Water Wetter" added, it increases the thermal whatchmacallit, and keeps corrosion to a minimum. Just a thought someone might want to try. But it will still freeze in winter!

Pete I am glad you found a solution and it might be the best one for you. I think you ride on the limits of what the cooling system was designed for so a bigger radiator from the S might be the easiest thing for you to do. You found a very unique but I bet pricey solution. How much does you radiator swap cost to do if you bought the stuff new.



The new rads and hoses and fan assembly cost in the neighborhood of $750. If I can sell my rads for $300 it will be a $450 deal,,, about the price of a good steering stabilizer. The peace of mind it will give me is worth that easy.


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