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Coolant Temps
dlrecord - June 1st, 2011 at 04:24 AM

Hi all,

1979 Bay Westy Deluxe with a 2.2LSubaru N/A and belly mounted radiator between the rails.

My question is about auto fan kick on and coolant temps. On our first day trip yesterday up the mountain, my fans were kicking on around 177*F. I hit a top temp of 212*F on a long and sustained pull up hill. I found the following graphic courtesy of ElusiveStranger (I believe) and am wondering if my coolant sensor is way too low for my engine?

http://vwkd.co.uk/vwkdpics/wo%20ac.jpg

My current aftermarket sensor is a 185*F and I was planning to up it to 195* as I believed that was what stock Subaru is. But the graphic above makes me wonder if I should be going up to 205*F? Thoughts? My system is a simple aftermarket dual fan set up with two relays and wiring kit. It is independent of the ECU. I have a manual override switch on the dash but the sensor should do most of the work while the bus is running.

Thoughts and advice appreciated!

ElusiveStranger - June 1st, 2011 at 08:44 AM

Just answered it on your other thread on here. Yes, it's waaaaaaaaaaaaay too low. Your stat's not even fully open when your fan kicks in

Use your ECU to control it or set your independent sensor to 95C and be done with it.

Joel - June 1st, 2011 at 09:46 AM

Quote:
Originally posted by ElusiveStranger
Use your ECU to control it.


This.


Several reasons.
Firstly the computer knows the ideal temps and it also Idles up so theres no voltage or rev fluctuation with the fan running

And secondly the temp coming out of the block is important, not all the way at the radiator.

What year EJ22?
its only the last ones in the mid to late 90s that run staged fans like the diagram above.

The rest just switch the fan on at 96c and off 90c.

dlrecord - June 1st, 2011 at 11:59 AM

Thanks guys. I debated running the radiator fans off the ecu but decided to take the simple route (in my mind at the time). My fan system is set up independent of the ecu, so it will be based on temp totally instead of temp and speed. I'll get the right sensor and run it.

On a potentially related thought, my warm idle seems to be right around 1300 rpms, which is more like cold start idle temps correct? Could the sensor be keeping the system in a cold idle loop and thus keeping the rpms so high? When warm, if I drop it into drive, the rpms will drop to around 800±. Otherwise in park it sits just north of 1300 rpms...

ElusiveStranger - June 2nd, 2011 at 04:59 AM

Just typing out loud here...did you have aircon fitted? The engine will idle up if it thinks the a/c's running (IIRC)

dlrecord - June 2nd, 2011 at 06:22 AM

No A/C fitted yet. It is on the list to do but is not there yet.

I just purchased a 210* thermo switch and will install and see if that has any effect.

ElusiveStranger - June 11th, 2011 at 10:54 AM

What bus are you running this in? T2/T3?
Subaru spent millions in sorting the cooling system.

We (well some of us) feck up their logic as we stick the rad lower than they (Scooby) intended - this causes grief (inherent grief)
Overcome this and all's well.

Stuff your switch - if it is a separate system?

Do it right :)