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E Model Cooling Problems

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I bought a used 2000 DRZ400E in December 05 and set it up street leagal for Arizona, but ride mostly off-road two track with some single track. It runs strong but I've had problems with it boiling over into the overflow tank with some coolent ending up on the rear wheel when going slow on single track 1st gear trails or running up hill on two track roads that are washed out to the point that I have to run in 1st or 2nd gear. above about 15 MPH it runs fine with no boiling over problems. The cooling system has no leaks, however the left side radiator has been dented in the side in the middle of the core about 1/2 inch and the three outside columns pushed togehter. I've tried Red Line Water Wetter, but it made no difference.

When I searched the DRZ400 forum on TT I saw fixes that included: changing to a KX500 cap, installing a fan and Thermostat like the S model, and Jetting. Have any of you on the forum experienced cooling problems after minimal radiator damage similar to what I have? What order would you suggest trying the above mentioned fixes? What would you recommend for jetting for an E model operating at 5000 to 7500 feet elevation (I'm in Prescott, AZ).

Any thoughts or suggestions on what I try next would be appreciated.

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I've experienced overheating. You cannot put around on tight trails in first going really slow with the stock cap without it boiling over atleast mine you couldn't. It does it if your hardly moving or idling for a while sitting still otherwise it seems fine. I still have the stock cap I never did change it. Really I haven't had it overheat much but I have on a few tight trails. I also had problems after my BB but not from going to slow as it did it when going wide open but a resivor was put back on and the headgasket changed as it seemed to be the culprit and it seems ok so far. At first the mechanic said it was still pushing coolant out but now it doesn't so it seems to be ok.

Is it the 1.6 cap thats reccomended or what cap is it? I'd change that in fact I probably should change mine.

My radiator now is dented up from falling on the trailer but it doesn't leak so I think it's still good and it isn't too bad just the outer two fins. You could put a new radiator on or send yours to Mylers and in theory it might help a tiny bit but I'm guessing its not that it's bent as when I've had it do it was before a bent radiator.

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Your altitude contributes to the boiling over. A 1.6 cap will help. After that, you just need air flow.

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As I commute on my "E" as we all know it's not hard to sit and wait from time to time due to traffic, lights etc. I did notice especially on hot days that my overflow tank would fill up a little, my solution was I replaced the stock coolant with Engine Ice and it's made a big improvement, my legs don't feel like there about to catch fire anymore! Although I never did any temp readings before or after, the old put your hand close and see trick proved it worked.

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What's the "1.6 cap" and where do you get it? And how does it help?

It is a cap that opens at 1.6 ATA verses the 1.1 ATA of the stock one. I think it was 1.1 at least. The cap is used on the kx500. I'm running one and have for quite a while now.

ATA is atmospheres absolute which is approx 14.7 psi.

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I'm going to try wiring computer fans to both radiators in a month or two. Already have the S wiring. Hope cutting the wire to the red light on the speedo didn't affect anything. I assume that bridging the wires to the thermostat/switch will let me test it.

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It is a cap that opens at 1.6 ATA verses the 1.1 ATA of the stock one.
So this is a cap between the cooling system and the overflow reservoir?

If so, the coolant runs hotter, right?

Anyone else have positive experiences with Engine Ice? I only hear that it's bogus.

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So this is a cap between the cooling system and the overflow reservoir?

If so, the coolant runs hotter, right?

Anyone else have positive experiences with Engine Ice? I only hear that it's bogus.

I have engine ice and boiled mine over on Friday. So whats the theory on the 1.6 cap? I dont get it.

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It holds the coolent back from going out the overflow and into the bottle.

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I went to the local Dealer and he said the cap off of an RM would work it's 1.6 ATA would this fit the DRZ and app. how much would/should a cap cost? the parts guy told me $26 for the cap :thumbsup: when I balked he said it's cheaper than a new motor! needless to say I didn't buy one. I'll shop around first

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It holds the coolent back from going out the overflow and into the bottle.
Which means the coolant can't expand, is under higher pressure, and runs hotter. Is that a good thing?

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Which means the coolant can't expand, is under higher pressure, and runs hotter. Is that a good thing?

It is if you are having problems, all it means is that the coolant boils at a higher temp, but it will still boil before damaging the cooling system.

But I would still have the damaged radiator checked for sufficient flow.

Neil.

:thumbsup::thumbsup::bonk:

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Yes, the 1.6 cap suppresses boiling so the engine runs hotter before it boils. A 50/50 mix of standard antifreeze with a 1 atm cap boils at 265 deg F. A 1.6 cap will raise it to about 273 deg. It is not particularly desirable to run hotter but it is better than boiling. I paid $14 for a Kawasaki 1.6 cap off the Kawasaki support truck at the Colorado 500 10 years ago. It was worth every penny of the $14.

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Noble pointed out that I had incorrectly stated the value of ATA. It is 14.7 psi when taken at sea level, less as you go up in elevation of course.

That is why I don't plan dives at the end of long days :thumbsup:

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