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I have an L98 installed in my 58 but want the fans to kick on much sooner than the 228° output from the Coolant Fan Temp Sw. or the C1 output that relies on the Coolant Temperature Sensor. Any suggestions are welcome. Currently I have a manual dash mounted switch to turn on the larger of my two fans but the smaller one (dependent on C1 output) never kicks on. I've got a DeWitt aluminum (stock replacement dimensions) radiator but still have overheating problems due to the high temp design of the L98 fan control.
Hot Rod Roy, I'm trying to use both the Coolant Fan Temperature Switch to control the HD fan and then use the Coolant Temperature Sensor to control the primary fan. Your suggestion for the CFTS is good and I'll buy one but that leaves the CTS and it's input to the ECM.
Last edited by mr-natural; 03-13-2018 at 07:51 PM.
OP - What year L98 and what ECM is used for control?
1226870 '85 OR 1227165 ECM '86 - '89 OR 1227727 '90+
Very important to be discussing the correct engine controls. Fan control varies somewhat ECM to ECM/year to year if you will.
Having 2 fans and the Dewitt then you could and likely have a very different than hinted control. 1st by the ECM and the 2nd by a separate switch or whatever. Is the fan arrangement something that was purchased from DeWitt or yet another vendor into the mix?
I don't have any idea what L98 you have, or what sensors are used in the L98's. My L83 spec is 238* on/ 201* off. The ACDelco sensor works great in my engine. If your sensor turn on temp is too low, your fan will never shut off, because the thermostat will be trying to get the engine up to a higher temp. You want the fan to turn on only after the thermostat is fully open.
OP - What year L98 and what ECM is used for control?
1226870 '85 OR 1227165 ECM '86 - '89 OR 1227727 '90+
Very important to be discussing the correct engine controls. Fan control varies somewhat ECM to ECM/year to year if you will.
Having 2 fans and the Dewitt then you could and likely have a very different than hinted control. 1st by the ECM and the 2nd by a separate switch or whatever. Is the fan arrangement something that was purchased from DeWitt or yet another vendor into the mix?
Sorry for not being more specific. I've got an 87 L98 with the 1227165 ECM.
Sorry for not being more specific. I've got an 87 L98 with the 1227165 ECM.
Do you know for a fact that it's (fan with ECM control) is wired correctly? You say 'never' so I'd think you leave the 'demand fan' OFF and let the temps get to 226° or greater and see if it does. If you want to maintain control of that fan by the ECM then you would have to have the PROM altered to the desired value.
If your 'demand fan' keeps the temps below what the CTS is seeing then it will never turn on.
Have you ever had a scanner on it to actually confirm what the ECM is seeing for coolant temps? Your particular situation I'd think requires that. I'd think that you could actually use only a scanner to determine the actual coolant temps that exist and compare to whatever you have for an IP gauge.
Whose shroud/fan arrangement are you using? Fan diameters?
Changing the 'demand fan' to a CFS as suggested by HRR I believe needs to be avoided until the actual running temps are evaluated in your particular situation (ARIZONA). There should certainly be 'specialty' CFS available but would likely require specialty bushing for cylinder head installation.
WVZR-1 I designed, and had built, the fan shroud which has two fans. The larger one is a 12" Perma-Cool rated at about 2,300 CFM and a 10" Perma-Cool rated just a bit lower. Both fan P/Ns are now discontinued so I'm not exactly certain of the CFM ratings. I just got a scan tool so I'll take your advice and look at the temps using it. I'll get back to you once I figure out how to use it. However, what does CFS stand for? I reread the posts by HRR and couldn't pick up the meaning.
WVZR-1 I designed, and had built, the fan shroud which has two fans. The larger one is a 12" Perma-Cool rated at about 2,300 CFM and a 10" Perma-Cool rated just a bit lower. Both fan P/Ns are now discontinued so I'm not exactly certain of the CFM ratings. I just got a scan tool so I'll take your advice and look at the temps using it. I'll get back to you once I figure out how to use it. However, what does CFS stand for? I reread the posts by HRR and couldn't pick up the meaning.
I used CFS (Coolant Fan Switch) - then it's easily understood we're not talking about device intended for ECM control of 'all' ECM temp related functions. I slip sometimes or just comment using same as what's in a thread but I've tried to correct that. CTS/ECT are more frequently used for ECM/PCM conversations.
You want to do several controlled drives using the scanner. Traffic - temp/humidity etc. Not quite the time of year for a 'worst conditions' but you'd have a base that you could compare to in 'heat of mid/late summer'. HRR in this thread used CTS and assumed everyone understood.
You could also use the scanning results to confirm IP Gauge accuracy.
What do you have for a thermostat?
The 'catch' with most current CFS available is the 'variance/tolerance' they're built with. An original GM/ACD hasn't been done for likely very many years. An acceptable after-market is mentioned to be on @ 221° with a +/- of 8°. I don't recall ever seeing an on/off of the ACD HRR mentions, only ON/closed. I always thought that resellers maybe created that
Ideally I'd think you would use a 2 terminal that has makes and breaks specifically assigned and probably more stringent QC.
Here's a temp switch manufacturers reference - in this list an SW505 is the ACD equivalent mentioned.
You need to remember every number mentioned is 'design/engineered' information and no OEM will ever mention tolerances in there comments - NEVER -
Your comment regarding ACD in 2016? I believe ACD likely ceased production years before that. Was it accurate when they did? Yes but with 'tolerances'!!
***Anyone with issues 'today' needs to confirm all!!
You need to remember every number mentioned is 'design/engineered' information and no OEM will ever mention tolerances in there comments - NEVER -
WVZR-1, why are you throwing rocks at me? I'm only presenting info that I believe might be a help to the OP. GreggPenn found the same info in 2012. Are you faulting his information, also? I think we all realize that every specification has a +/- tolerance. Certainly there are tighter tolerance devices, if you're willing to pay for military grade ($$$) parts! I've been using the D1855B since 10/2006.
Can you verify your info that the Wells SW505 is the same as the ACD D1855B?
Last edited by Hot Rod Roy; 03-15-2018 at 02:11 PM.
WVZR-1, why are you throwing rocks at me? I'm only presenting info that I believe might be a help to the OP. GreggPenn found the same info in 2012. Are you faulting his information, also? I think we all realize that every specification has a +/- tolerance. Certainly there are tighter tolerance devices, if you're willing to pay for military grade ($$$) parts!
Can you verify your info that the Wells SW505 is the same as the ACD D1855B?
I ain't tossing rocks
This ain't a C4 where you check for the lower deflector, clean the trash from the condenser/radiator and drive on.
1st of all there's no reason for the OP to even consider a 'recess pin' specific switch. I see absolutely no advantage, another reason I posted the link to temp related control devices. I also asked him to explain the cooling fan arrangement. He answered all with information I understood. I think I 'get it'.
I can tell you that if you take the GM 14043275 or ACD D1855B to nearly any auto parts jobber you'll be presented with a switch of similar specifications.
A NAPA equivalent just mentions on at 213 - 229 A NAPA purchase advantage might be the 36mo warranty. NAPA is FS112.
Regarding the OP - He mentions having a scanner and I imagine pockets 'deep enough' to resolve a cooling issue. I've seen same/similar issue 1st hand with many projects. Cooling is almost always an issue.
http://dccontrol.com/constant_temper...ontrollers.htm I've been using one of these for many years on my 86. It works great. Just set it at the temperature you want and it varies the fan speed (from 0 - 100%) to maintain that temperature.
This ain't a C4 where you check for the lower deflector, clean the trash from the condenser/radiator and drive on.
1st of all there's no reason for the OP to even consider a 'recess pin' specific switch. I see absolutely no advantage, another reason I posted the link to temp related control devices. I also asked him to explain the cooling fan arrangement. He answered all with information I understood. I think I 'get it'.
I can tell you that if you take the GM 14043275 or ACD D1855B to nearly any auto parts jobber you'll be presented with a switch of similar specifications.
A NAPA equivalent just mentions on at 213 - 229 A NAPA purchase advantage might be the 36mo warranty. NAPA is FS112.
Regarding the OP - He mentions having a scanner and I imagine pockets 'deep enough' to resolve a cooling issue. I've seen same/similar issue 1st hand with many projects. Cooling is almost always an issue.
Gentlemen all, here's the latest. Using a scan tool proved easier than it should be and it did reveal that my primary fan (the one controlled by the ECM) did not come on at 228°. I didn't want to go higher than that as because I'm gun shy - don't want to warp the newly installed heads. I manually switched on the aux fan and it lowered the temp to about 212°. This was done in my garage on a cool AZ day but the temps sort of tracked with the 58 dash gauge. So from what you folks have mentioned and the link to posts by GreggPen it appears I can purchase a CTS that may take care on 1/2 of my problem but that leaves getting the primary to turn on at say 200°. I'm running a 160° thermostat which behaves exactly like the 180° one I replaced. I know this all makes sense since I'm obviously limited in my cooling by not getting both fans to come on.
Gentlemen all, here's the latest. Using a scan tool proved easier than it should be and it did reveal that my primary fan (the one controlled by the ECM) did not come on at 228°.
Do you know for a fact that your fan is wired correctly? You can do anything you like regarding switches etc but if the fan you wish to control isn't wired correctly you'll accomplish nothing! Do you have the '87 FSM (or any year) to use as a guide for cooling fan wiring?
*****You're relying on a dash gauge of the '58? Is this a restoration piece, an original or perhaps a quality retro gauge? You're using what for a sending unit to that gauge? Brand & part#? Is it correct for the gauge?
*****I see maybe 5 different threads regarding your TEMP GAUGE
You can't do the cooling evaluations in a garage or sitting still!
Your TEMP GAUGE sender is between 1 & 3 (left) or 6 & 8 (right)?
Back in '13 you had a conversation with 'MrWillys' regarding PROM tuning, that conversation was regarding cooling. What did you do then?
This has nothing to do with 'cooling' but has your 'cold start' been eliminated or defeated? If it has that gives you another coolant port available for switch, sender for evaluations.
Going back to your original post -I don't understand why you've got the 'smaller' fan looking for ECM control. Typically the ECM would control a primary fan and usually the larger of the 2. Are these fans 'side by side' or just how are they arranged in your fabricated shroud?
WVZR-1 thanks for all the feedback here's a few facts:
1. I do not recall how I resolved the temp gauge issue I had years ago where the gauge would peg in 10 seconds or so.
2. The gauge is original and unaltered but I did do a characterization long ago and have every reason to believe it's a "good" indicator of temp.
3. I have not had any reprogramming done. Once I get all major issues resolved and VSS installed I'll look into that.
4. My cold start issue was resolved once I learned just how radical my cam was and I increased my idle speed to about 950 RPM.
5. I do have an 87 FSM and that is how I wired the car. When shorting pins 1 & 2 at the ALDL the primary fan comes on as it should
6. While I do not have the original specs for the model fans I purchased from Perma-Cool the current specs for a 10" fan show 50 CFM (2,350 CFM) greater flow than the flow of the 12" fan. Therefore I don't think it's an issue that I'm using the 10" as primary. Below is a photo of my custom designed shourd & fans.
WVZR-1 thanks for all the feedback here's a few facts:
1. I do not recall how I resolved the temp gauge issue I had years ago where the gauge would peg in 10 seconds or so.
2. The gauge is original and unaltered but I did do a characterization long ago and have every reason to believe it's a "good" indicator of temp.
3. I have not had any reprogramming done. Once I get all major issues resolved and VSS installed I'll look into that.
4. My cold start issue was resolved once I learned just how radical my cam was and I increased my idle speed to about 950 RPM.
5. I do have an 87 FSM and that is how I wired the car. When shorting pins 1 & 2 at the ALDL the primary fan comes on as it should
6. While I do not have the original specs for the model fans I purchased from Perma-Cool the current specs for a 10" fan show 50 CFM (2,350 CFM) greater flow than the flow of the 12" fan. Therefore I don't think it's an issue that I'm using the 10" as primary. Below is a photo of my custom designed shourd & fans.
Interesting shroud/fan arrangement.
I understand your comments!
Look and see if both of these sensor/sender are actually present and wired in your car. Sender/sensor to the left is 'cold start' - if it ain't wired/in use/functional I have an idea. Dumb idea? I know not!!!!
03-13-2018, 05:56 PM
Heavy Duty Coolant Fan Control (overheat issues)
