Help, CR-V over heating

zak410, Mar 17, 10:44pm
my old crv over heating.
Its fine on open road, gauge stays at 50% but when I have to stop like at a traffic light, the temp gauge goes all the way to the top; when I move again, gauge come down to half way until next stop.
What can cause that!
Also the expansion bottle gets full, the radiator low on water doesn??

tmenz, Mar 17, 10:48pm
Fan(s) not working! Radiator gets a draught through it when moving but not when stopped.

zak410, Mar 17, 10:52pm
thanks for your reply but yes, fans are working

morrisman1, Mar 17, 10:54pm
possible candidates include the waterpump, if its knackered it might only pump properly at higher rpm. Radiator is more likely, if the cooling system hasnt been properly maintained then it could have blocked cores and only part of the radiator is being effective.

Without a proper diagnostic its very hard to work out cooling system faults as they are never predictable!

zak410, Mar 17, 10:59pm
thanks morrisman, the cooling system always maintain and always had proper coolant in it, but the car has 200K km and a block radiator has been also suggested by a friend of mine, (he is not a mechanic though)

morrisman1, Mar 17, 11:15pm
take the car for a drive and when you get back check the radiator to see if there are any cold spots on the radiator. Thats probably all the mechanic will do initially.

That doesnt explain the loss of coolant in the radiator, perhaps it is leaking somewhere it will prevent it building up sufficient pressure. Get a pressure test done on the system (should be free unless the mechanic is money hungry) and also keep a lookout for leaks around the front end of the engine.

zak410, Mar 17, 11:25pm
great advice morris, I will do that tomorrow, local mechanic is nice, thanks a lot both of you.

scoobeey, Mar 17, 11:39pm
cost me 110 buk for a pressure test!

zak410, Mar 17, 11:46pm
thanks for that, you may be right but of course this is the most dreaded option, but I can drive 100km the car will only show heating when I stop but is cool on the open road again, could this still happen with a head gasket problem! I don??

intrade, Mar 18, 12:49am
its your fan not working right. poster 2 explaind why also.

intrade, Mar 18, 12:54am
fan working means nothing if it just makes a few rotations wont do squat to cool it down . when the fan kicks in you can watch the temp nedel go backwards or it simply is not spinning fast enough. He confirmed that on open road it is normal . open road wind is forcing loads of airthru the radiator just like a correct working fan should.

zak410, Mar 18, 1:06am
possibly that also, I noticed the fan is coming on and of if i idle the car for half an hour, (after topping the radiator) but the fans are usually not on when the temp gauge goes to the top;
what could cause the fans to work well but not always!
I will see our local mechanic tomorrow and have first a pressure test and go from there, this board is awesome to get info, thanks all very much.

intrade, Mar 18, 1:50am
you need a auto electrition. i got a car where the fan is not spinning fast enoug cant be stuffed wasting my time . i just wire a kit i got from supercheap auto to controll the fan on its own temp sender and releay on it soon. Paid 200$ to have the internal fanfor heater fixed byautomotive electrition for the same car already.

zak410, Mar 18, 2:06am
thanks intrade, iI will have that check tomorrow too, it may be the cause yet as the fans seem to come on at mid-hot but I noticed them not working when i stopped to open my gate, after a long drive and the temp gauge was near the top when I came back to the car! thanks

franc123, Mar 18, 6:04am
Well thats immediately suspicious isn't it.You need to be getting the fan circuit checked, a few older Hondas IIRC did suffer from problems with radiator temp sensors failing, maybe even a relay playing up!And hope like hell you haven't got a head gasket or head about to need attention.

zak410, Mar 18, 6:29am
thanks franc, for your info, i will see an auto electrician tomorrow, your info is very good. any thing in particular I should ask him to look for!

zak410, Mar 18, 11:49pm
I went to an auto-electrician today and yes the fans are working, they come on at 90 degrees not for long but the temp goes down fast.
But as I noticed before, when the car over heat the fans are not always working, the auto-elec think that it *may be* because by then the water level may be too low to activate the sensor. (!)
Anyway, I got the car booked to a radiator place next week to check for blockage in the radiator and for a pressure test.
And yes I do put the heater on when the temp goes to far up.
also, there is no way to put my hands on the radiator to check for cold spots as the fans cover most of it.
Thanks all for your help and hints.

fordcrzy, Mar 19, 3:50am
my bet is water pump. Not sure about the CRV but a lot of hondas run the water pump off the cam belt.the water pump bearing fails and you get water leaking out from around the pulley.then the bearing fails all together and valves meet pistons.

zak410, Aug 23, 8:59am
just an update for all of you kind people that answered to help.
I went to a radiator specialist in Whangarei and yes, the radiator had a blockage in it.and also the radiator cap didn??