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View Full Version : Overcooling issue maybe ?

Paulpen
02-23-2008, 10:02 AM
Here goes.

RB25DET in a S13 with a Revotec electric fan sender in the top hose and 306 HDi fans.

If I leave the car to idle then it will warm up nicely, the needle will sit in the middle of the gauge and the fans will cut in - happy days your thinking !

When I drive it though the needle goes right down and I do mean right down - below the bottom mark.

Also the top rad hose always seems to be hotter than the bottom one - is this right ?

Its got a brand new Nissan thermostat in and is not loosing coolant from what I can tell. Have tried bleeding the system when hot and cold via the 10mm bolt on top of the inlet but still the same.

Has anyone else had this problem or have any ideas what it could be ?

Im starting to think there is a blockage or that the gauge sender is faulty but how can I test these along with the temp sender to the ecu ?

Pleaseeeeeeeeeeee :rolleyes:
Grenade180sx
02-23-2008, 10:27 AM
get a aftermarket gauge.. stock clusters can be skecthy

the top hose should always be hotter as it is the hot side for the water coming off the motor.

hope this helps!
BoostedCoupe
02-23-2008, 11:35 AM
the temp sensor is bad. mine did this on a ka. i could let it warm up and as soon as i drove it the temp gauge hit bottom.
blownmotor
02-23-2008, 01:27 PM
there are two sensors usually for nissans one for ecu other for gauge
Anto
02-23-2008, 01:31 PM
Water temp sensor and water temp sender are two different sensors..
The water temp sender is the one going to your gauge, I'd suggest you spend the money on an actual water temperature sensor gauge, especially with a nice RB in there.
drift freaq
02-23-2008, 01:56 PM
Water temp sensor and water temp sender are two different sensors..
The water temp sender is the one going to your gauge, I'd suggest you spend the money on an actual water temperature sensor gauge, especially with a nice RB in there.

I would second this. When I ran my RB I monitored my water temp off my PowerFC because the stock temp sender is pratically an on/off switch.

If you are going to monitor your temp by the stock gauge and a temp sender on the engine, I recommend getting a S13 temp sender and replace the one that came on the RB.
Paulpen
02-24-2008, 03:16 AM
I would second this. When I ran my RB I monitored my water temp off my PowerFC because the stock temp sender is pratically an on/off switch.

If you are going to monitor your temp by the stock gauge and a temp sender on the engine, I recommend getting a S13 temp sender and replace the one that came on the RB.


Many thanks chap - ill swap a CA18 sensor in for the moment as got one in the engine that came out. Gauges is next on the list once I get paid :-/
g6civcx
02-24-2008, 06:27 AM
Don't trust the stock sensor. Get a true mechanic's thermostat that you can stick into the radiator (available at any service station) and get back to us.
Paulpen
02-24-2008, 08:05 AM
Update time then !

Tried covering half the rad with cardboard to see what happens. Same as it was at idle but when driving the needle went about 2mm high on the gauge.

Then took the sensor off my CA18 that just came out and put that in and bingo - all SEEMS to work ok now. Not sure wether to be confused and cautious or just happy and forget about it now !