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Topic: Wacky Temperature Gauge (Read 7206 times) previous topic - next topic

Wacky Temperature Gauge

Well I was having problems with my temperature gauge a while back, and after replacing the t-stat, and the sending unit, its still a little wacky. With the heater off the gauge seems to read normal, about half when its been running, maybe a tad bit more.

When I turn the heater on the gauge goes up around 3/4. I'm wondering if anyone has heard of this before, it it happens to any of you guys, and what might cause this.

Wacky Temperature Gauge

Reply #1 –
Air in the system?
11.96 @ 118 MPH old 306 KB; 428W coming soon.

Wacky Temperature Gauge

Reply #2 –
lol.... sorry,... ive been having the same issuie,... and all i can come up with is maybe the fan clutch is burning out, cause im betting you dont turn on the heat til the car is warm, so everything seems  ok, then when the heat goes on, it seems fine but then gets a little hotter and hotter till it stays around the R and M, and if you get on it for a little, or get aggressive it goes Past the M..........if the clutch is bad, it wont pull enough air through the radiator....
 
 thats how mine is anyway, i havent gotten the clutch until i go get my injectors and comp........
 just me two cents anyway!!!!!
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Just enjoyin the ride!!!!

Wacky Temperature Gauge

Reply #3 –
Anyone know how to test a fan clutch? Is it still if the car is cold, and you try to turn the fan it should spin freely?

Wacky Temperature Gauge

Reply #4 –
Quote from: Cougar5.0;265830
Air in the system?


I checked that too. That was what my father suggested as well.

Wacky Temperature Gauge

Reply #5 –
When you say "turn the heat on" do you mean the blower?
How about if you turn the blower on with out the heat on? does that make the temp gauge go up?
Are the fuel and oil pressure gauges also affected?
What I am building up to is a possible flakey IVR.

Wacky Temperature Gauge

Reply #6 –
Quote from: softtouch;265873
When you say "turn the heat on" do you mean the blower?
How about if you turn the blower on with out the heat on? does that make the temp gauge go up?
Are the fuel and oil pressure gauges also affected?
What I am building up to is a possible flakey IVR.


x2 and
Does the increase happen instantly or gradually?

Fan clutch bone cold> you should not be able to spin it by hand more than a half turn.

next time you park the car, pop the hood and watch the fan as you shut down. observe the qty of rotations, try to guess either rotations or spins.  The fan should stop within a second or two of shutdown.  just count it 1 one thousand, 2 one thousand.

To me, it would run hotter with the heat off.  Running the blower cools the core and helps cool the coolant.  your getting the opposite response, tells me im probably lookin for electrical issues.
Too much current draw perhaps.

Wacky Temperature Gauge

Reply #7 –
Quote from: softtouch;265873
When you say "turn the heat on" do you mean the blower?
How about if you turn the blower on with out the heat on? does that make the temp gauge go up?
Are the fuel and oil pressure gauges also affected?
What I am building up to is a possible flakey IVR.


The fuel gauge does not move during this, not enough to notice anyway. Its a base cluster so no oil pressure gauge, just a light.

Wacky Temperature Gauge

Reply #8 –
Quote from: jcassity;265897
x2 and
Does the increase happen instantly or gradually?


To me, it would run hotter with the heat off.  Running the blower cools the core and helps cool the coolant.  your getting the opposite response, tells me im probably lookin for electrical issues.
Too much current draw perhaps.


It happens within 15 seconds or so. I would have though the temperature gauge would decrease when the heat/blower are on too, as you are taking hear away from the motor.

I'll check the fan clutch today and let you know.

Wacky Temperature Gauge

Reply #9 –
jcassity,

when you say you shouldn't be able to spin it more than half a turn by hand, do you mean like spinning it and letting it off and allowing the fan to free wheel, or by keeping your hand on it all the time?

Wacky Temperature Gauge

Reply #10 –
When it's cold, ideally, it should be hard to rotate, when it's warm, the viscous materiel inside the clutch allows it to turn a little more freely.

If the gauge goes higher than normal right after you first start up after a long time sitting, I'd suspect an electrical problem first.
Stock gauges are kinda vague anyway, if you can afford it, buy a small coolant temp gauge, and install it and see how warm it's really getting...odds are your temp gauge might be slightly off.
'98 Explorer 5.0
'20 Malibu (I know, Chevy, but, 35MPG. Let's go brandon, eh)

Wacky Temperature Gauge

Reply #11 –
Quote from: jpc647;269112
jcassity,

when you say you shouldn't be able to spin it more than half a turn by hand, do you mean like spinning it and letting it off and allowing the fan to free wheel, or by keeping your hand on it all the time?


He means when it free-wheels.  If it just keeps going, it's done.  Replace the clutch.
-- 05 Mustang GT-Whipplecharged !!
--87 5.0 Trick Flow Heads & Intake - Custom Cam - Many other goodies...3100Lbs...Low12's!

Wacky Temperature Gauge

Reply #12 –
spin it and let it free wheel.

just spin and let go.

This would be with a bone cold motor though.

with a hot motor,, dono, probably the same result.

temp fix---
remove one of the bolts that attaches the clutch to the fan blades.
install a longer bolt
install until you feel resistance then just keep turning until you feel something kinda break.

you just put the guts insided the clutch in a bind with the longer bolt,,,thus making the fan solid.

enjoy your new noise maker,, sounds good with a solid fan

Wacky Temperature Gauge

Reply #13 –
Well this issue came back. Now I know it only happens when it is cold out. I took the radiator cap off and put my temperature measuring device into the coolant it read 130 degrees.  I pushed it further down and got readings as low as 90 degrees.  I put it right near the temperature sending unit and it was reading around 200, this is right on the intake manifold. So I think it's impossible the car would be running hot, or hotter than it should be. I spun the fan clutch and it doesn't spin very long when cold. I didn't seem to notice a difference between warm and cold though. The radiator does flow, it is old, but I can see it flow freely. It is fine in the warm weather, so it must flow. Would temperature affect a fan clutch?

I have a thermometer unit with a metal probe that displays a digital readout of the temperature. I tested it, I hold it up outside, and it read like 32 yesterday and that is what the thermometer on the outside of the house read 33. I put the over on to 200 yesterday too and put a pan of water in there, i took it out after like 20 mins and my thermometer read 202. So it's pretty accurate.

I figured with all of the new people around here lately, someone might have an idea.

Wacky Temperature Gauge

Reply #14 –
Quote from: jpc647;348378
Would temperature affect a fan clutch?



Yep. As the engine temp rises the coil allows silicone fluid to enter the clutch and when it fills the grooves in the clutch body and plate  it engages  the clutch.
FOXLESS!!

1994 Lincoln Mark VIII