About a month ago, my car began acting oddly. VTEC wouldn't engage and it had a 4,000rpm rev limiter. The car wasn't warming up completely. I hooked up my laptop for some datalogging, and noticed that my coolant temps were hanging around 140-145 when driving, and only going up to 155-160 at idle in traffic.

I replaced the t-stat with a 'premium' model from Autozone (180 degree), refilled the system and bled out any air that might have been trapped. Now the car warms up to 155-160 driving, up to 166 at idle on a hot day. My mixture before was ~30% coolant, ~70% water, and a bottle of water wetter since the car had recently spent a good amount of time on the dyno.

So this weekend I drained the system, and refilled it with a good 50/50 mix. Started her up to cycle the fans, circulate the coolant and make sure she was topped off, and I noticed my fans kicked on about 162! Again, I saw only up to 165ish temps before the fans would kick on and knock it down to 155.

Now I've got like 70% of the radiator blocked off to get it to cruise at 190 degrees. This car liked to run 195-200 degrees stock. My closeloop control is set at 170, and fan control is at 180, so wtf's going on? Possibly a bad thermo sensor?

 

Bump for some input.

 

drill a 1/8" hole in your t-stat or 2 1/16" inch holes in it

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dohczccrx &raquo;</TD></TR><TR><TD CLASS="quote">drill a 1/8" hole in your t-stat or 2 1/16" inch holes in it </TD></TR></TABLE>

What does this accomplish?

 

The thermostat does not control the fans; the thermo switch does this.

Did you make sure you put the thermostat in correctly? The bleed hole goes in the upward position if i remember correctly.

Are you POSITIVE you got all the air out of the cooling system?

Back to the fan switch, did you replace it at the same time you replaced the thermostat?

 

"drill a 1/8" hole in your t-stat or 2 1/16" inch holes in it "


Well that suggestion would allow coolant to still flow past even when the thermostat is closed. This would drop your temp even more than it is now.

great advice...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SuzukaBlueAP2 &raquo;</TD></TR><TR><TD CLASS="quote">The thermostat does not control the fans; the thermo switch does this.

Did you make sure you put the thermostat in correctly? The bleed hole goes in the upward position if i remember correctly.

Are you POSITIVE you got all the air out of the cooling system?

Back to the fan switch, did you replace it at the same time you replaced the thermostat?</TD></TR></TABLE>

Yep, long portion of t-stat toward engine. It only fit one way IIRC, cause of the pin in the bleed hole.

I can't be 100% sure that all the air was out. I squeezed the hoses while filling it, getting it to cycle, and did manage to bleed lots of air out. I figure it'd be an OVER heating problem if air was trapped in the system.

Did NOT replace the fan switch with the t-stat. Wasn't aware of the continuing cooling problem at that time. Is that thermo switch directly relayed to the fan, or does it send a control signal through the ECU?

OBD1 P61 ECU.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BLACKLIST138 &raquo;</TD></TR><TR><TD CLASS="quote">"drill a 1/8" hole in your t-stat or 2 1/16" inch holes in it "


Well that suggestion would allow coolant to still flow past even when the thermostat is closed. This would drop your temp even more than it is now.

great advice... </TD></TR></TABLE>

That's what I was thinking...


Modified by AFAccord at 11:13 PM 9/5/2008

 

Playing around tonight...

The cooling fans kicking on at 160 had me worried, since the ECU is set to kick them on at 180. So i pulled the plug off the thermo switch, and voila!! fans don't kick on at 160 now, but 180 where they should.

I pulled the cardboard out from in front of the radiator, so we'll see how she does. I'm still concerned that she won't hold her temp up when cruising down the highway. :fingers crossed: