Coolant Temperature

[Josh51]

For a while now my coolant temperature reads at the very top of the Normal line when warmed up (see pic). I changed the temp sender unit out and it reads the same. Is this ok? I own a temperature gun, where could I take a temp on the engine to see if it's in a ok range? What is an ok range? Thanks

 

[Josh B]

That does look a bit to the high side, but I don't know how you could check something else agin it

 

[rusty ol ranger]

Dont run a 2.9 hot.

Bad things happen.

If it were me i would shoot your heat gun around the area of the factory coolant temp sender.

That being said its possible its a wireing/cluster issue. But the rest of the gauges look pretty normal,

You could go and buy a aftermarket sunpro or whatever gauge and wire in. Then you can keep an eye on it real time.

When does it get hot? At idle? Cruising? All the time?

 

[Josh51]

It idled in the driveway this morning for about 10-15 mins and the needle got to the top line of normal. If I drive for long distances the needle never goes above the top line of normal.

I like the idea of picking up an aftermarket gauge, they are pretty cheap

I took some temp readings today, 1st number is idling in the driveway after 15 mins, 2nd number is after driving for about an hour

Thermostat housing 196, 208
Temp sending unit 168, 182
Block around the thermostat housing 188, 203
upper portion of water pump 177, 186
Lower portion of water pump 145, 191

After idling i shot at different places around the block and it was always around 200...except for near the headers

What do you think of the readings

 

[broncc]

Those readings seem fine. It sounds like your temp sensor is the wrong resistance. I don't know if there is a bad lot or what but I put a WVE temp sensor into my car (2.3 sohc) and I read the same amount at normal operating temps.

 

[rusty ol ranger]

It idled in the driveway this morning for about 10-15 mins and the needle got to the top line of normal. If I drive for long distances the needle never goes above the top line of normal.

I like the idea of picking up an aftermarket gauge, they are pretty cheap

I took some temp readings today, 1st number is idling in the driveway after 15 mins, 2nd number is after driving for about an hour

Thermostat housing 196, 208
Temp sending unit 168, 182
Block around the thermostat housing 188, 203
upper portion of water pump 177, 186
Lower portion of water pump 145, 191

After idling i shot at different places around the block and it was always around 200...except for near the headers

What do you think of the readings

Those dont sound bad at all.

Id get an aftermarket gauge atleast till you diagnose your factory one.

2.9's like to crack heads. Its really their only weakness

But for shits n giggles verify your fan clutch is working

 

[RonD]

1/2 on a Ford Temp gauge is 200degF
So your gauge is off or the wire from the Sender to the gauge is bad

Cold engine key off
Unplug the temp senders ONE wire connector
(If the one you changed had 2 wires then you changed the wrong one)
Turn on the key
With wire unplugged gauge should stay at C or less, if it goes up a bit then Sender wire is partially shorted to ground or gauge is, in the cluster

Ground the one Sender wire to battery negative with a jumper wire
Turn on key, if it was off
Gauge should now go all the way up to H, or above

If gauge stays at C with no wire connected and goes to H with wire grounded then wire and gauge are OK, sender is bad, even new one


The 2 wire temp unit is the ECT sensor, added to fuel injected engines and only used by the computer, 5volt 2 wire sensor

Dash temp gauge uses a 12volt Sender, 1 wire, and used since the 1930's for dash board temp gauges, they were grounded by engine metal
In the late 1990's when plastic intakes were starting to be used the Senders got a Ground wire added, so also 2 wire

 

[Josh51]

Awesome write up. Easy to follow. Per your test, my sending unit is prob bad. Unplugged and the gauge stayed at C, grounded and it went to H. I'll grab a new one and report back

 

[RonD]

Leave some bare metal threads at the bottom of sender

 

[Josh51]

will do

 

[Josh51]

Here's my follow up. I changed the temp sender, put in a new motorcraft 192 degree thermostat, did an oil change and changed the air charge sensor. The needle still sat at the top of the normal line but sometimes a bit below.
I bought a bosch mechanical gauge. I just drove 20 miles on streets and the temp ran around 190 most of the time. Once I stopped and turned the truck off it went up to 200 but never above. Let me know what you guys think

 

[alwaysFlOoReD]

That's fine

 

[franklin2]

Keep your aftermarket gauge. I do not like Ford's gauges. You might want to get a aftermarket oil pressure gauge and see what your oil pressure really is.

 

[wildbill23c]

The cluster on my 87 Ranger is pretty wonky most of the time too, fuel and temp gauges are never right...aftermarket coolant temp gauge is pretty much a must for these trucks as they get even older, and more electrical gremlins show themselves. I run a lower temp thermostat, I'd rather have slightly cooler heat, than deal with the overheating potential in the summer especially running the AC...still need to swap out my fan clutch, probably do that this coming spring and put the HD clutch in, or try and see if I can find some electric fan somewhere that I can install and get rid of the mechanical one altogether.

Temps sound pretty good, sensors are kind of hit and miss sometimes, compounded with old wiring, and a wonky gauge cluster and you'll never know most of the time if you fixed the problem or what the real problem actually was LOL.

 

[Josh51]

I'm contemplating keeping it but I love the non clutter look of stock, the aftermarket tach I have drives me crazy because its so big

My fuel gauge is a bit wonky. When I fill up it reads significantly past the F marker. Goes down fine as I use gas but is is still annoying.

Every ford vehicle I've owned the oil pressure read perfectly at the 50% mark

Thanks everyone for chiming in