Gaspi101

Thanks to many of you here at the forum, I've successfully swapped my 96 manifold for a 2003 with the aluminum crossover. However, I'm very hesitant to drill into the aluminum to tap another hole for the coolant temperature sensor. SO, I bought a brass tee fitting and hooked both the temperature switch and the coolant temp sensor to it. (see pictures) Good news is the coolant temp sensor seems to do its job, and the fan turns on at appropriate intervals. Bad news is the temp switch is barely reading temperature, and I get zilch on the dash display. I need help deciding what to do. Here are my ideas. Will any of them work? 1. Buy the sensor/switch (2-in-1) that the 2002 manifold goes with, and attach all FOUR wires (2 from each sensor plug) to the same. 2. Relocate the temp switch (BUT WHERE, and most importantly, HOW!!)--I have one idea: I've cut off the coolant tube going from the manifold to the heater core, and plugged it. Could I put the switch here? It won't be in an aluminum housing (as it should be), but clamped to a rubber hose. Will this correctly read the temperature? 3. Leave the damn thing alone and pray I don't overheat.
Barring all of these, I guess I'll have to tap that hole after all. But if I *%&$ up the drilling, I'll RUIN the manifold. If anyone can give me good instructions on how to go about this, PLEASE! As soon as I'm done, I'll post all the pictures of the project here. Again, thanks in advance to all of you mechanics!!!!

Gaspi

Picture 1: Tee fitting w/sensors attached
Picture 2: Place where hole for coolant temp sensor should be tapped.

[IMG]local://upfiles/12394/39DA9EFB17B14DB5A50C59C3D35D2600.jpg[/IMG]

[IMG]local://upfiles/12394/9A37DE930F6D4AF0B99383C9B587FC6F.jpg[/IMG]

Gaspi101

It's a 96 GT (v8) by the way...

roundman

the sending unit for the temp gauge needs to see a coolant flow by it to read accurately. If you loop the heater hose line back to the water pump so there is a constant flow in it, then you could move the switch to that line mounted in a tee and it should work OK then. Don't try to drill and tap the manifold unless you feel comfortable doing it. You could pull it and take it to a machine shop and have them do it for you though if the other install method doesn't work out.

Gaspi101

Not sure I understand. Let me see--If I get another tee fitting (one with male adapters on the Ts), then I could cut one of the radiator hoses, and place the T in the middle with the temp switch attached? Is that right? Otherwise, would not attaching all the wires to a 99+ sensor (the one that is supposed to go the manifold I have.) Thanks for the input man!

gaspi

Djs94stang

The bottom line is that the way you have it...the coolant flow is dead ended. In fact, you may even get an air pocket in the T. I am not familiar with the cooling system layout on the 4.6 but you will need to place the temp sensor somewhere where there is coolant flow and as close to the engine/manifold as you can get. Maybe you can get an aftermarket thermostat housing that has extra fillings...I don't know. Or you could tap into the 5/8ths inch hose going to the heater core as close to the engine as possible. You are smart not drilling and tapping the manifold. Typically, any tapped holes are put into a raised boss to allow enough material to thread. If you tried this on a flat area you may not get enough threads for the npt.

Gaspi101

You are absolutely right about the air pocket. When I took off the tee fitting, I had no coolant ebb out. However, the coolant outlet on the far left of the manifold that goes to the heater core and I had previously capped off permanently does get god coolant pressure (if you uncap it, the coolant comes straight out). So went ahead and plugged this with the coolant temp sensor. Now, the computer is actually not revving periodically and it turns the cooling fan on and off (especially with the A/C on). So, I think that fixed that. And on the one hole inthe manifold I put the temp switch. The dash registers very little temp rise, but it does register it. If the temp switch is now on the manifold, why isn't it reading temperature correctly?

I thought that the coolant temp sensor goes to the ECU, and the temp switch directly to the dash. Am I wrong? Also, I don't think I can get it drilled, as I'd have to take the manifold clean off--and doing the swap took me three days (working mostly during Miami nights). Also, why does it have to be a coolant FLOW, instead of the sensor being submerged in it? Placing the sensor as a cap to that outlet going to the heater core should logically work. If not, why not? An ideas?

Thanks! You guys are the best.

Djs94stang

It sounds as though you are not running any hoses to the heater core and are using the fitting boss that would normally have the heater hose going to it. I believe you are correct regarding how the switch and sensor are hooked up. Unfortunately, I am not too familiar with the 4.6 but coolant flow is important for a couple reasons. First off, you need some flow in the area of a sensor or switch so that the temp locally at the switch or sensor will accurately reflect the engine temps. The only thing I can think of is that if you have intended to block off the heater core and not use one of the intended outlets (to the heater core) in the manifold then perhaps you have an area in the manifold that is more stagnant and doesn't get accurate engine coolant temps as quick as it should. The other cause to consider is the thermostat. Is it installed correctly? Did you have to mess with it when you did the manifold?

Casper98GT

Well, here is my answer. I am going to write up a "How to " for this when i do mine. Im a Ford tech and this will be a breeze and i have thought this through before i do it.... The 4.6 MOD motor has a coolant drain on it... ITs on the block above the oil filter. Remove the drain and put the sensor in it. lol.... easy fix and it works great.

Casper98GT

Only bad thing is ( if you are not skilled ) is cutting the wires and splicing them into longer wires to run around the head.

Wessy

why not drill the water outlet (t-stat) housing? It comes off without ripping the top half of the engine off and it'll be easy to drill.