AFAccord

I've already wasted my breath on this topic in the Tech forum, so I'm bringing it here.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AFAccord &raquo;</TD></TR><TR><TD CLASS="quote">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 172, and fan control is at 180, so wtf's going on? Possibly a bad thermo sensor?</TD></TR></TABLE>

<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>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AFAccord &raquo;</TD></TR><TR><TD CLASS="quote">Yep, long portion of t-stat toward engine. It only fit one way IIRC, cause of the pin in the weep 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?
</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AFAccord &raquo;</TD></TR><TR><TD CLASS="quote">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:

</TD></TR></TABLE>


So I've eliminated the thermo switch that was cutting the fans on at 160. I flushed the cooling system out completely with a water hose, and refilled with 70% coolant 30% water, bleeding it thoroughly. The car still warms up to 170max when sitting in traffic on a hot day (94-98 degrees), but back down to 160-165 when I get moving down the highway. The cardboard is back in...




Modified by AFAccord at 9:14 AM 9/11/2008

AFAccord

25 Views and 0 replies...

AFAccord

42 Views and 0 replies...

sxm5369

have you tried bleeding it using the bleeder valve? oh yeah dude is that your accord on avatar, looks just like mine

sxm5369

oh yeah and what setup are you running i didnt see it in the post

AFAccord

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sxm5369 &raquo;</TD></TR><TR><TD CLASS="quote">have you tried bleeding it using the bleeder valve? oh yeah dude is that your accord on avatar, looks just like mine </TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AFAccord &raquo;</TD></TR><TR><TD CLASS="quote">I flushed the cooling system out completely with a water hose, and refilled with 70% coolant 30% water, bleeding it thoroughly.</TD></TR></TABLE>

Did that. I figure if there was air in the system, i'd be experiencing an OVER heating issue though.

F23A1, fully ported/polished/built head, ARP head studs, I/H, OBD1 converted P61 ECU, tuned with eCtune.

Head studs were installed long before this issue came up. Just installed the current head with a new gasket a couple weeks ago, and the problem still exists. Even swapped ECT sensors out, so I know I'm not getting false readings.


Modified by AFAccord at 9:23 AM 9/12/2008

GhostAccord

How far did they port your head? Maybe the thinner walls dissipate the coolant temps faster. The faster moving cooler air coming into the intake side may have something to do with it. What are your IAT temps like, do you have any EGT probes/readings. Do you have access to any sort of thermal imaging device/ laser temp gun that you can get readings from different spots on your head?

This is just a suggestion of coarse. I'm sure the amount of porting done to a head will change the characteristics of the water jackets cooling properties somewhat....But by how much? I'm not sure if it would be enough to cause this much of a coolant temp change??
Just seems to reason that if your IAT's and EGT's are low then your Coolant temps would also be lower.

AFAccord

I can monitor the ECT and IAT through datalogging. I've got an EGT gauge and probe, but they're not hooked up. I'm going to try to get ahold of an IR temp gun this afternoon, and try to hit different parts of the engine to make sure I'm not seeing cool at the sensor, and much hotter in other places. Besides the upper and lower hoses, and both sides of the head, are there any specific locations I should look check the temp?

AFAccord

I got the motor checked out with an IR pyrometer. With my cardboard blocking the radiator, heater on, and car at idle, the ECT held steady at 177 degrees.

Shot the upper hose where it enters the head with a reading of 204.

Shot the lower hose, inches before the thermostat housing with a reading of 156.

Shot the thermostat housing itself with a reading of 190.

So I'm thinking my ECT Sensor readings might be 10-15 degrees low. Even if this is the case, I'd still like to run a bit hotter when rolling down the highway. I'm going to do more checks with an IR gun at different temps, and might end up skewing my ECT's readings so the ECU doesn't act so inconsistent when driving.

Just for an example, yesterday I started the car up to run to the store. The car was already about 100 degrees, and was up to full op temp by the time I reached the highway, at least according to the temp gauge. I pulled on to the highway, getting into 1st gear a little, and VTEC engaged, so I had to have been above 142. Into second, and VTEC engaged again, but by the time I hit 3rd, the temp gauge had dropped nearly 1/4" inch, at which point VTEC was disabled because the motor was too cool. All this before 50mph.

I can't imagine the cooling system should have THAT MUCH effect from such little air flow. This occurred with the radiator nearly 70% covered, and the thermostat should have been fully closed at those low temps.

What gives?

AFAccord

Update:

Problem still not resolved. I still have most of the radiator blocked off with cardboard. Thermo switch is still unplugged. The motor warms up to 180 while idling until the fans kick on and drop it to ~177.

Now with the weather cooling considerably, I'm having more and more problems keeping the car warmed up. Driving down the highway the other night when it was ~55 degrees out, my temps dropped down to ~145 with the heater on. I turned the heater off, and they came up to ~158. This is still well below my threshold for closed loop operation. So my fans aren't even kicking on going down the highway, and my radiator is almost completely blocked off, and I'm STILL not running hot enough??

How would the car be cooling this well? The only other thing I can think to do is to swap to a less efficient half-radiator, but that costs money and still doesn't explain why the stock cooling setup is doing this!

P_Adams

First thing I'd do would be to determine which of the sensors (Fan sensor/ ECM engine Temp) and the thermostat were lying.

With household items (pan of water / stove (heat sourse) and a themometer) and a volt/ohm meter, you can visually verify the t'stat opening point, and the fan switch trigger points.
The ECM Engine temp Sensor will be a little more problamatic, unless you've a scanner (and it sounds like you do.)

The point is; Manually verifying the electronic operations - somethings not right.
With a known heat sourse (heating water and the thermometer readings) you can compare what you're seeing with what you're getting.

P