mr-natural

KingtalOn I already have the two ports in the block filled, one with the aux fan switch and the other with the stock 58 sending unit, turned down and threaded to 3/8 NPT in order to fit the 87 block. So that leaves me with three options, the ECM to do the controlling, running both fans off the aux switch (which I don't like as an alternative), or using a thermostat (which I tried a long time ago and didn't like the results). So it seems I've got to get the ECM to do the work, unless I'm missing something of course.

Kingtal0n

Thermostat isn't going to bring temps down. thats a fan. Why not remove one of those switches and replace it with a proper switch that does what you want for all fans. I mean why not run "aux fan" to all the fans instead of just one. It doesnt need to feed power to the fan, it just flips a relay on and off. So install as many relays as you have fans and run them all to 1 single signal switch to turn on or off.

there are also 100 other ways to get a 3/8" into the coolant. they sell adapters for radiator hose. You cut the hose in half and install the sensor in the hose directly. Its ugly but it works and its cheap. If you had a turbo with coolant plumbing you could tap into that. think of somethat that receives coolant that you can tap into: there are all kinds of places. How about the head? The head usually has plugged or unused temperature sensor ports. I know on my 862 castings there are 2 temp sensors, one in each head, and the computer only needs 1 so I have 1 hole left "open" which is simply plugged. maybe find one of those.

Plus remember the throttle body gets coolant in OEM applications. there must be some lines around there. And how about all the heater core stuff? heater core holes coming off the water pump, you can take into one of those. If they are plugged just drill a brass plug and tap it 3/8".

gpierce

Tridon makes a coup!e of dual temp fan switches .TFS104 and TFS107 have a look at those.

WVZR-1

OP - You've posted to the other thread but disregard this one. I maybe don't understand that.

I asked in #19 I believe an important question that if answered could lead to maybe an inexpensive either short or long term solution.

Not having the car present it's maybe a bit more challenging because it has to be assumed that everything is wired correctly and related components all function well.


Not having valid information on the fans used presents it's own challenges. If there's labels on the fans still maybe you ask Perma-Cool for specifications or maybe GOOGLE could be a source. Their current catalog offered to the masses for 'download' appears to be a 2013 publication. Hard to tell from your posting string when you did the fans? '09 maybe?

Has 'cold start' been defeated, removed or functional?

Why the new cylinder heads?

I'd maybe attempt something like this if you're confident in what's wired currently. You say you have a 'demand switch' you're using currently and you mention A - B turns on a fan. The same fan or the other fan? You know both fans run? If the demand switch operates the same fan do you know it's wired correctly and maybe doesn't take the ECM control out of the works.

If 'cold start' is defeated/removed or maybe even disregarding I might be tempted 'if the car were here and wiring checked' do this. I'm quite sure the CS switch is a thread match for 3/8-18

Put a 185° switch at 1 & 3 location to control primary fan, replace the 'cold start switch' (post #19) with a 195° switch wired to the other. This arrangement I'd think would allow you to at least evaluate possibilities. A friend suggested maybe the other way around. Who knows?

Disregarding CFM I'd have maybe chosen a 12" for primary vs the 10" just because of the radiator surface and maybe it's location to the coolant hose which can't be seen in your snapshots. When moving I'd think it's maybe irrelevant.

You have to consider that any C4 comments regarding the AUX ain't actually relevant because that was for a 'pusher' forward of the condenser.

Switch brand maybe only because of insulator 'color' I might choose Maradyne. Just a WAG but when you call them for technical advice the first question is maybe - what color switch?

MFA108 = 185°




MFA109 = 195°



I didn't see tolerances on the Maradyne site to 'off/open' temps so I'd call them but Summit mentions MFA108 'off' to be 170° and for the MFA109 Summit is in conflict with 'on/close' temp(200°) also but mentions 'off/open' to be 185°.

You mention using the '87 FSM for wiring but what do you actually have for brand/part# of relays.

This would allow you to drive and scan for evaluations. My friend mentioned an LED for each to monitor. I thought that would maybe be a nuisance.

In #19 I mentioned 'dumb idea' - who knows?

This would eliminate the tuning for a very long time maybe and if it proved reliable/function maybe you actually don't.

Are both fans quiet? My friend said this might matter to him.

I've never used Maradyne nor has my friend but the 'color' stuck out. Cooling fans are their business so maybe it's worth a conversation.


*** I'd maybe also do a new ECM CTS/ECT sensor (whatever) after another scan and just compare values to a previous right after t'stat opening. The sensor is inexpensive.

mr-natural

ZR-1, yep, I have both the sender and the sensor as shown and wired properly.

WVZR-1

Is the 'cold start' functional? Do you think required?

mr-natural

ZR-1, yes I have the sensor/sender combination and they are wired properly. My scan tool has been a help pin pointing the exact temperatures I'm dealing with. Somewhere, some years ago, I obtained a thermostat (looks like the one that comes with the Derale 16314 kit) that in desperation I recently installed. It seems to be working fine and keeping the temps below 180° unless I'm idling. However the temps here in AZ have been pretty cool but that won't last long. I installed the thermostat bulb along the upper portion of my shroud.

WVZR-1

I understand the 'wired properly' but is the cold start functional at the fuel rail or maybe more importantly is it a necessity.

I believe you have the '87 FSM so maybe you review the 'cold start' circuit test and operation @ 6E3-A-22., 6E3-C-2. If you feel you need 'cold start' and it's 100% operational fine. If it doesn't function OR if you felt not needed then maybe the multiple switched fan control could be considered.

Have you ever used an IR TEMP gun to check the temps across the top of the radiator tank? You mentioned the 10" used on the demand switch, just looking at the shroud cut out that appears to be the right fan. Correct? It just seems that the left fan might offer better option (area vs cfm) in relationship to upper radiator hose. A WAG? With an IR I'd think it easily confirmed.

I don't recall how accessible the lower tank of a 'straight-axle' era car is but if accessible I'd maybe IR it also. I'd think there's little turbulence to interfere with accurate IR readings.

Bulb is top left or right of shroud? Set at what temp?