TCCoA Forums banner

1 - 20 of 27 Posts

·
Registered
Joined
·
16 Posts
Discussion Starter #1
Hello all, so I have a 1997 4.6 Tbird and I recently had to get a new radiator fan due to the past ones internal gear breaking keeping the fan from turning completely and along with that a new water pump and 170 degree thermostat.
what I havenoticed so far is that with the stock new thermostat rated at 195 the engine temp would shoot up past middle and be in the high temperature close to overheating but not completely I’d say like 3/4ths dang near but with the new thermostat the temp would stay cold about 3/4ths as well then maybe 20mins into driving it would go to the middle then go to 3/4ths like I’ve mentioned earlier but not as bad
What do you all recommend I do? Is this a concern? The car never overheated with all this going on but it’s got me worried because this never happened before. Usually it would stay in the middle and stay stable but the the engine temp would always flounder (PS the fan seems to work but very different from the previous)
Thanks!
 

·
Super Moderator
1994 Cougar XR7 DOHC/5-Speed
Joined
·
18,626 Posts
The factory gauge isn’t particularly trustworthy, and a defective anti-slosh module can cause erratic and high temperature readings. Its best to verify, if you have a scan tool, a tuner or OBD II scan gauge you can read the temperature the EEC sees and it will be substantially more accurate. There’s actually a good possibility the temp may have been normal all along (typically between 200-210°) with the stock water pump and 195° thermostat, until the fan failed anyway(internal gear?).
 

·
Super Moderator
Joined
·
11,064 Posts
The fan settings in the tune make more difference than the thermostat does.
There's no gear in the fan. :)
iirc, stock fan is low speed is on at 195, off at 185.
High is on at 205.
 
  • Like
Reactions: 1RedTBird

·
The Parts Guy
Joined
·
7,583 Posts
I can pull up the stock '97 4.6L fan on/off schedule at home, but IIRC, it's much higher than that.

With a lower temp thermostat, you'll see the coolant temps come down while cruising on the highway, but you're at the mercy of the fan settings when traveling below ~40 MPH or sitting still.

And yes, the stock "gauge" doesn't tell you much at all. Read the ACTUAL coolant temps if you're concerned.
 

·
Registered
Joined
·
2,162 Posts
With the indicated temp bouncing around, you may have an air pocket in the system from the last job. Try driving around for a little while with the overflow cap loose, or just let it run with the front end jacked up and cap off.

Al
 
  • Like
Reactions: 1RedTBird

·
Super Moderator
Joined
·
5,428 Posts
And to add one more note:

There's a Technical Service Bulletin (TSB) for several years Fords where the sending unit will read erratic or HIGH ( 2010-01-21_122141_tsb95-18-05.pdf (justanswer.com) )

There's another one for it reading erratic or LOW ( 1983 Ford Bronco TSBs & FSAs (Recalls) for '83-96 Broncos & F150s picture | SuperMotors.net )

Before I panicked, especially with it being OBDII, I'd poll the ECU with a competent scanner and saw what temps it was seeing.

Add to it that age is starting to take its toll on the anti-slosh module, and, well ...

RwP
 
  • Like
Reactions: 1RedTBird

·
The Parts Guy
Joined
·
7,583 Posts
With the indicated temp bouncing around, you may have an air pocket in the system from the last job. Try driving around for a little while with the overflow cap loose, or just let it run with the front end jacked up and cap off.

Al
I'd advise against that, as doing so has the propensity to make quite a mess. The expansion tank (not an overflow reservoir) on a 4.6L will deaerate just as well with the cap secured as with it off
 

·
Registered
Joined
·
16 Posts
Discussion Starter #8
Alright sweet so for the most part I more than likely have a faulty engine temp reading. I’ll let the car run for a bit and then use a OBD 2 sensor to check the engine temperature? Also should I opt for a new engine temperature sensor?
 

·
The Parts Guy
Joined
·
7,583 Posts
I'd start with reading the actual coolant temps before bothering to change anything else.
 

·
Super Moderator
Joined
·
5,428 Posts
I’d do that via OBD 2 right?
Yep. Also, you can use a non-contact thermometer on the thermostat housing to check; although it's not accurate to the actual temp, if it says 175F and your dash says 110F or 225F ...

Well, the dash gauge is not working right.

RwP
 
  • Like
Reactions: 1RedTBird

·
Registered
Joined
·
16 Posts
Discussion Starter #12
Yep. Also, you can use a non-contact thermometer on the thermostat housing to check; although it's not accurate to the actual temp, if it says 175F and your dash says 110F or 225F ...

Well, the dash gauge is not working right.

RwP
Alright awesome thank you very much!
 

·
Registered
Joined
·
2,162 Posts
I'd advise against that, as doing so has the propensity to make quite a mess. The expansion tank (not an overflow reservoir) on a 4.6L will deaerate just as well with the cap secured as with it off
Hmmm. I've done it many times, never spilled a drop. I'm not talking about taking a hwy trip, just driving 10 miles around from cold. But just running the car with the front end jacked up is a safer way. Also, you don't fill it all the way to the very top, that would likely overflow. Common sense.

Al
 

·
The Parts Guy
Joined
·
7,583 Posts
Hmmm. I've done it many times, never spilled a drop. I'm not talking about taking a hwy trip, just driving 10 miles around from cold. But just running the car with the front end jacked up is a safer way. Also, you don't fill it all the way to the very top, that would likely overflow. Common sense.

Al
All you're accomplishing by doing so is lowering the boiling point of the coolant by keeping the system open. The deaeration chamber within the expansion tank will capture the air in the same fashion with the cap on or off. There is no reason to run the engine with the cap removed.
 

·
Super Moderator
1994 Cougar XR7 DOHC/5-Speed
Joined
·
18,626 Posts
Alright sweet so for the most part I more than likely have a faulty engine temp reading. I’ll let the car run for a bit and then use a OBD 2 sensor to check the engine temperature? Also should I opt for a new engine temperature sensor?
Drive around like you normally would with the scanner monitoring the whole time, when you see the gauge reading high and fluctuating it will be a reality check for it.

With the age of these cars it’s just as likely the source of the gauge fault is the slosh module as it is the sensor. The needle tends to be steady if it’s just the temperature sensor, the slosh module going bad tends to make the needle bounce and fluctuate at random
 

·
Super Moderator
1997 Thunderbird 4.6, 1998 Mark VIII LSC
Joined
·
10,056 Posts
FWIW, in the stock calibration the low speed fan comes on at 210. High speed at 220.
 

·
The Parts Guy
Joined
·
7,583 Posts
FWIW, in the stock calibration the low speed fan comes on at 210. High speed at 220.
There ya go. Saves me from having to go find my SCT dongle to access Advantage.

To reiterate to the OP, with the stock tune file and that colder t-stat, coolant temp will drop on the freeway, but you're still at the mercy of the fan temp schedule when at low speed/stationary.
 

·
Registered
Joined
·
15 Posts
Just a month or so ago I replaced my fan with a new one after I tried everything else and learned that the temp sensor on the driver's side had a wire that was intermittently not conducting signal. Had engine running and the Forscan was reporting coolant temp climbing towards 200 but no fan despite it going into closed loop at about 195. Seems that low speed came on around 210 and shuts off around 204. I had low/no pressure in the A/c system so I could not get the high speed on which is why i changed fans. If ECT doesn't reach 195 you will stay in open loop and richer fuel ratio.
 

·
Super Moderator
1997 Thunderbird 4.6, 1998 Mark VIII LSC
Joined
·
10,056 Posts
Actually the PCM switches to closed loop at a lower temperature than when the thermostat opens. It's a combination of time since startup, startup temperature and current temperature. I would have to look but in general, by the time you hit 160 or so, it's in closed loop. If the engine is in the low-mid 1xx range it might go into closed loop within a few seconds of startup.
 

·
Registered
Joined
·
16 Posts
Discussion Starter #20
Drive around like you normally would with the scanner monitoring the whole time, when you see the gauge reading high and fluctuating it will be a reality check for it.

With the age of these cars it’s just as likely the source of the gauge fault is the slosh module as it is the sensor. The needle tends to be steady if it’s just the temperature sensor, the slosh module going bad tends to make the needle bounce and fluctuate at random
How do you replace the slosh module?
 
1 - 20 of 27 Posts
Top