Raidiator water problem?????

My 02 wr426 has been losing water every time I go ride. There are no leaks anywhere that I can find. I have used coolant as well as water and after I ride 1-2 hours I have to put about 1/2 to 3/4 of a quart back in. Occasionaly it will fill the over flow bottle but even when it does not over heat at all there is still fluid missing, any suggestions that I could easily check?????/ :)

I just posted a similiar issue with my 03 WR450. I noticed a few drops of anit-freeze when I cold start the bike if it hasn't been started in a while. Check and see if did you notice the leak coming out of the bottom of the water pump housing. There is a predrilled hole there for some reason. :)

Sounds to me like the bike is getting hot and just evaporating the coolant /water mixture off. Have you checked to make sure you have the right mixture of water and coolant? other than that it may be jetting causing the bike to heat up more than normal. just my opinion.

How much water can evaporate in a couple hour ride?????

I am having some jetting issues right now so maybe thats a small part.

The bike sits in my clean garage so I know its not leaking anywhere that I can find. I thought that maybe there is some debris in there that is clgging it somehow?? Just not sure

If you havn't any leak from the bottom of the water pump housing and any hose or pipe or O-R or radiator of the coolant system there are another two possibilities:

1 A damage in the radiator cap: it's possible a failure in a one of the two seals, so the cap can't mantain the correct pressure in the coolant system and water get out. You can check this adding a water tank at the end of the tube from the right radiator and to control if there are some leaks.

2 It's possible the failure of the head gasket; if there is this problem there is a lot of smoke exaust too, a white smoke. But this kind of problems in the up-to-date bikes is very difficult.

3 It's still possible, but very difficult, a porous, very little hole in the the head or in the cylinder. In this case it's possible adgjust the problem with a specific product without change the head or cylinder

After talking with my neighbor who is a very competent mechanic, he said my problem was very likely that the bike is running to lean. He also said that typical radiator fluid is not thin enough to run properly through the bike.

I will go back to stock jetting and proper anti-freeze and see if this solves the problem, if not I will start checking other things as mentioned in these threads.

Thanks all for help :)

May be a long shot but check all your carb hoses, crankcase breather etc. for mud or other obstructions. Trailriderjoe, on a WR400 had a major coolant leak this fall due to really nasty mud on Saturday and the bike overheated and leaked on Sunday.

I try and figure it out this weekend. Merry Christmas to all! :)

There is a predrilled hole there for some reason.

-It's a weep hole. If the seal goes bad you will start to "weep" fluid out of it.

He also said that typical radiator fluid is not thin enough to run properly through the bike.

Yes usually it's like this, but it's possible the contrary; it's very, very, very, very, very difficult, but it's possible :)

my 03-wr450 also leaks while kiking on a cold start out of the weep hole but quits after it starts the dealer said it was nothing to worry about?

my 03-wr450 also leaks while kiking on a cold start out of the weep hole but quits after it starts the dealer said it was nothing to worry about?

I don't know... It's possible that when engine became hot after the first minutes after start the house pump dilatations quits leaks.

You have to control water level in the radiator: these kind of seals fail quickly, so you can check the problem before that it becames dangerous for you engine

Make sure you are using a 50/50 mix of antifreeze and water(distilled is best).

You may need to do a cooling system pressure test the special tool needed is sold at sears(cooling system pressure tester).

I have looked at them in sears but did't remember if they came with the "small" radiator cap adapter for japanese vehicles.

Take your rad. cap with you to make sure this tool will work.

The only thing I didn't like about the sears tool was it was made out of plastic---Snap-on or Mac tools makes metal ones that I know come with the "small" rad. cap adapter.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now