Coolent Sensor in Pass. Head - Third Generation F-Body Message Boards

Johnny Blaze · 05-16-2005, 01:12 PM

Which sensor is this? What does it do / control? How many wire hook up does it have?

Car is an 88 350 TPI

bluegrassz · 05-16-2005, 01:16 PM

Should be the temp sending unit for the fans. Should have one plastic terminal that slips on it. Should be between the #6 and #8 cyl.

vernw · 05-16-2005, 01:16 PM

On my 91 that is the secondary fan switch, controls when the second fan kicks off and on. The sensor is the driver's side head is the one that controls the temp guage in the dash. They are totally separate and pretty much unrelated to each other.

bluegrassz · 05-16-2005, 01:19 PM

Quote:

Originally posted by vernw
On my 91 that is the secondary fan switch, controls when the second fan kicks off and on. The sensor is the driver's side head is the one that controls the temp guage in the dash. They are totally separate and pretty much unrelated to each other.

I just had noticed he said passenger side and fixed my post.

Same time as you were posting. lol.

Johnny Blaze · 05-16-2005, 01:20 PM

Do you have to get it from the Dealer? I tried to get it at autozone, and they only had the one in the intake, and the one for the driversside.

vernw · 05-16-2005, 01:21 PM

They should have it, tell them it's the secondary fan sensor switch.

bluegrassz · 05-17-2005, 10:37 AM

Quote:

Originally posted by Johnny Blaze
Do you have to get it from the Dealer? I tried to get it at autozone, and they only had the one in the intake, and the one for the driversside.

Check out this: Cooler Temp sensor

This will help the fans come on sooner and keep the motor cooler.
Summit also has one and maybe Thunder Racing. Might as well go to a cooler switch while you are changing it.

Johnny Blaze · 05-17-2005, 03:22 PM

I have already changed the one in the Drivers side head, with a Hyperchip one to kick the fan on sooner. Thanks

vernw · 05-17-2005, 03:34 PM

You sure about that? I've always heard the one in the driver's side head was strictly for the guage. Front of the intake manifold was the primary fan switch like the Hypertech one you mentioned, and the secondary fan switch was in the passenger side head. At least that's the way my 91 TPI was configured.....

ploegi · 05-17-2005, 04:06 PM

The computer controls the primary fan, turn it on at like 230 degrees, off at 190? something.... Not sure of exact numbers. The switch in the passenger head controls secondary fan. However.... The computer pays attention to the secondary fan, and when it comes on, turns on the primary as well. Putting a lower temp switch in the passenger head, will turn on BOTH fans at the lower temp, and the computer is basically taken out of the loop, as the temp switch is lower than the normal "on" temp for the primary.

The sensor in the drivers side head is for the gauge in the dash only.

Johnny Blaze · 05-17-2005, 04:15 PM

So, the sensor I bought for turning the fan on at a lower temperature needs to go into the passenger side head?

vernw · 05-17-2005, 04:17 PM

Yep. And that will control only the second fan. The primary fan is controlled by the computer. I'm surprised your gauge even worked with that Hypertech sensor in the driver's head (or did it?)

Johnny Blaze · 05-17-2005, 04:25 PM

Car is not all the way back together yet, so I do not know.

The sensor that goes into the drivers head, is it the same as the one for the intake? What does the one in the intake do?

Roads88 · 05-17-2005, 04:37 PM

From TGO FAQ:

Quote:

The secondary fan has its own temperature sensor in the bottom of the engine block (passenger side) and will turn on when both of these conditions exist:

I see a sensor in the head as well.

What am I Missing?!?!

I would like to go to a cooler sensor as well.

Johnny Blaze · 05-17-2005, 04:42 PM

The only sensor i see in the pass bottom of block is the knock sensor.

Roads88 · 05-17-2005, 04:49 PM

Me Too.

The FAQ thru me

But at least I woll not have to drain the whole raditor.

Roads88 · 05-17-2005, 04:58 PM

QUOTE]The sensor that goes into the drivers head, is it the same as the one for the intake? What does the one in the intake do?[/quote]

I think thats the one that sends to the ecm (in a dual fan car)[

vernw · 05-17-2005, 05:22 PM

Lower passenger side block is the knock sensor.

Passenger side head is the secondary fan switch. If if is a "cooler" switch than the primary fan, will turn it on too. (not sure on that one)

Driver's side head is a temp sender strictly for the instrument panel gauge.

Front of the intake manifold is the computer's engine temp sensor. Used for lots of things, like determining when and how much cold enrichment is needed ("choke" stuff), turning on the primary fan, amount of spark advance and fuel based on the engine temp, etc.

As far as interchangeability, the connectors are different for the gauge sender vs. the ECM's temp sensor.

Johnny Blaze · 05-17-2005, 11:07 PM

Okay, here is what auto zone lists.

Which is which, and where does it go?

Coolant Temperature Sensor. Wells Part Number SU109

Cooling Fan Switch - Radiator Wells SU502

Temperature Switch Wells TU66

Johnny Blaze · 05-18-2005, 11:33 AM

bump

vernw · 05-18-2005, 03:18 PM

Without seeing the parts, I'm guessing a little here since I have no knowledge of manufacturer part numbers...

Go to www.napaonline.com for pictures of the following:

MPETS4015SB this is the coolant temp sensor that goes on the front of the intake manifold, notice the connector type

MPETS6641SB this is the temperature gauge sender, notice the connector type

MPEFS112SB is the cooling fan switch, not the type connector on it.

These are all part numbers for an 88 IROC 350 TPI (wanted to make it easier for you)

Does that help?