Triumphrat

dano · 03-24-2005, 12:40 AM

i have a 99 daytona that is overheating, it seems to only happen when the bike is being ridden, it doesn't happen when at idle. the shop did all the usual stuff....replaced fluid, rad. cap, thermostat, and checked hose for kinks. the shop seems to believe that the head gasket or the head itself might be cracked..what do some of ya think? i can fill in more info if someone cares to reply.
danowakefield@msn.com

parrycm · 03-24-2005, 10:49 AM

If the head gasket is gone, or the head is cracked then there should be some pointers:

1) Coolant loss - is the coolant level going down?
2) If it is going down, where's it leaking to?
a) Is the engine oil emulsifying due to coolant ingress? Does it look whitish, especially round the oil filler? (water vapour condenses where it's cooler). You might consider draining the oil in a clean clear container, and looking for water settling out at the bottom.

b) If it's leaking into the cylinders you might notice that it's spitting more water than usual out of the exhaust? Note: check this with the engine warmed up as engines produce a lot more water when cold due to the rich mixture.

c) Does the coolant itself contain oil? Can you see bubbles appearing in it? Any sign of external leaks?

So, unless you are seeing one of these indicators, I would look for other possibilities.

Fan switch - is the fan coming on when it gets hot?
Temperature sender/sensor - if it's not too expensive just screw in a new one and see if the problem continues.

SWare · 03-24-2005, 02:42 PM

I noticed in another forum that your engine recently underwent major repair at your dealer. Total dissassembly it sounds like. Have they considered an error during reassembly? A blocked water passage, damaged or blocked water pump, etc.?

stan

[ This message was edited by: SWare on 2005-03-24 13:06 ]

SWare · 03-25-2005, 03:03 PM

Got your PM that this was a different engine.
Since this one has not been that far apart you can probably eliminate improper reassembly. If you are not loosing coolant to the oil or combustion chamber it is unlikely a cracked head or head gasket is the problem.
The leak could be very slight so don't rule it out completely yet. One thing I've seen in cars is the combustion chamber leaking into the water jacket. This will cause excess pressure what appears to be a boil over. The loss of coolant then would cause you to actually overheat. How quickly this happens depends on the size of the leak. I had a car that did this like 5 mins after startup. Boiling over luke warm coolant had me scratching my head for a bit.

If coolant level is normal when it overheats then it almost has to be a problem with coolant flow. A plugged radiator, blocked or crimped hose, or a problem with the pump. You said the hoses were checked. What about flow testing the radiator and checking the water pump?
Anything blocking airflow to the radiator like debris or damaged fins?

Chris mentioned the fan and that should be checked, but you indicate the problem is when riding. The fan would be important at idle and maybe stop and go traffic. If it does not come on when required it would lead to overheating in those situations. If it is getting hot on the open road then it is not the fan. There should be enough air flow over the radiator at road speeds.
Does the fan come on before it overheats?

stan