running hot

JBT · Postby **JBT** » Mon Nov 27, 2006 6:15 am

sabretooth wrote:If the car is overheating while moving in stop start then it's not going to be your fan.

That's precisely what caused Red5 to overheat the other day.

davamb · Postby **davamb** » Mon Nov 27, 2006 9:54 am

Thanks guys,

same conclusion I've come to overnight, the heat exchange efficiency is low, it must be the radiator. Fair cop I s'pose for 16 years old. I don't know if there's any value in trying to get these things cleaned, I think once they're that blocked up, replacement is the only option.

Boags · Postby **Boags** » Mon Nov 27, 2006 10:44 am

JBT wrote:
sabretooth wrote:If the car is overheating while moving in stop start then it's not going to be your fan.

That's precisely what caused Red5 to overheat the other day.

Surely when you are at speed and overheating it isn't the fan, it is flow. When it is stop start, the fan is the only thing moving the air though... :?:

JBT · Postby **JBT** » Mon Nov 27, 2006 12:11 pm

davamb wrote:............it must be the radiator. Fair cop I s'pose for 16 years old. I don't know if there's any value in trying to get these things cleaned, I think once they're that blocked up, replacement is the only option.

It's easy enought to get it out and take it to a radiator place. They can give it a core clean and test, especially if it needs a new top tank at the same time. New radiators from Mazda are fairly expensive. Many people fit aftermarket ones if a replacement is needed.

kitkat · Postby **kitkat** » Mon Nov 27, 2006 2:00 pm

Boags'MX5 wrote:
JBT wrote:
sabretooth wrote:If the car is overheating while moving in stop start then it's not going to be your fan.

That's precisely what caused Red5 to overheat the other day.

Surely when you are at speed and overheating it isn't the fan, it is flow. When it is stop start, the fan is the only thing moving the air though...

bout a month ago i was mucking around, forgot to connect the fan plugs back up.... anyway, went for a drive throught surfers, had the aircon on. The car didnt start to overheat untill about 2mins after we stopped in the traffic, even then it only crept up very slowly.

davamb · Postby **davamb** » Wed Nov 29, 2006 10:46 pm

Stopped by my mechanic's place tonight and he had a good look over the car. Did all the obvious stuff, tested the thermostat and reverse flushed the cooling system. Then we ran the car up for a while and observed the coolant flow into the radiator and the temps across the radiator. All seemed to be working fine and heating up nicely. Finally the fan cut in. The half of the radiator in front of the fan promptly cooled down, but the rest stayed stink hot. In fact the fan never cut off! So the radiator's got to be partially blocked up even though it all looks pristine inside. So it looks like it's off to the professionals to be dismantled and cleaned out or a new radiator. Tomorrow I'll have quotes for both.

jules · Postby **jules** » Thu Nov 30, 2006 10:00 am

Sounds like a plan!

Jules

davamb · Postby **davamb** » Thu Nov 30, 2006 11:27 am

$90 for a dismantle, clean and test, $440 for a new one from Mazda, $395 for a new (genuine) one from Mania (+ shipping).

Theeenk I just might try the clean.

davamb · Postby **davamb** » Sun Dec 03, 2006 8:45 am

Done now and all sorted. Ended up being $170 as a new top tank had to be fitted - the plastic was crazed and getting pretty brittle. The left hand (passenger) side of the radiator was pretty well blocked solid. A bit unusual apparently, normally they block up below the inlet pipe rather than the other side.

So, some advice for others with dodgy cooling - the rad can be fixed, at less than half the price of a new one.