Adding 1/2 litre coolant after every ride.

madmax80

~SPONSOR~
Oct 10, 2009
14
0
Just bought a 91' KDX 250.
Previous owner spent $2500 on engine, has maybe 10 4 hr rides on it. New crank, piston, rings, bearings, etc. I think he had it bored too. I can ask him exactly what was done if needed.
Never checked rad level after my first couple rides, then checked it last week, was down 750ml. When I pulled the rad cap off there was a rush of air, dont know if it was pressure or vacuum. Topped it off with 750ml 50/50. Rode today for about 4 hrs, took another 500ml after it was completely cold.
I also noticed today while riding there was a constant vapor trail out my exhaust, like when you start your car in cold weather and the choke is on. Temp here today was 4 deg. Celsius.
Engine has never overheated or boiled over since rebuild.
What should I check first? I read here somewhere that the inner pump seal may be in backwards. Should I check that first and if in correct assume either head or base gasket?

Thanks.
 

madmax80

~SPONSOR~
Oct 10, 2009
14
0
Will doing a cooling system pressure test be of any value or do I have to do a leakdown?
 
Last edited:

Tom68

Member
Oct 1, 2007
407
0
My KDX250sr was in a similar situation, radiator pressure test was OK, bore was too worn for a leakdown test. I rebuilt it, went to 72mm bore, had too make my own head gasket and hasn't lost a drop of water since. Recovery bottle is connected.
Obviously I had the most minute head gasket seepage.
 

sr5bidder

Member
Oct 27, 2008
1,463
0
circle back on yourself while riding if it smells sweet check the head for cracks/warpage and heagasket

copper spray a gasket from peratex works really good, I spray both sides and let it dry before installing
 

madmax80

~SPONSOR~
Oct 10, 2009
14
0
I'm running atf and it looks just like the day i put it in. I've been using that strawberry scented synthetic so my exhaust always smells sweet. The last couple of rides the exhaust steams constantly so I must be ingesting coolant into the combustion chamber ? Is it just the headgasket that handles coolant or could it be a basegasket ?
 

sr5bidder

Member
Oct 27, 2008
1,463
0
the coolant doesn't go that far down to the base it has a hose in and a hose out of the water pump like the 200's right? ..probably the head gasket... hopefully not a home brewed porting that got into the water jacket
 

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