North American Turbocoupe Organization



Temp Gauge
Rob H Offline
Member
#1
I'm wondering how normal it is to have the temp gauge reading at the high end of normal, even climbing out of normal.
When I first got my car it was running fine, but the gauge said it was again the high end of normal, but would go into the red. We found then that both of the fans were actually seized, I'm not sure how the car had not overheated. We replaced the fans, and things seemed fine.
I've been on a couple long distance runs, one I just got back from. It wasn't particularly hot out, but from what the gauge was saying, I was at risk of overheating. I didn't have many options so I continued on with fingers crossed that this is normal.
The car doesn't behave funny. The temperature doesn't go any higher when I come to a stop. The fan doesn't continue to run after the car is shut off. I don't hear any gurgling from the coolant reservoir.
If it wasn't for the gauge, I wouldn't even suspect anything is wrong. The coolant was replaced when I did the heater core a couple years back.
Reply

Jeff K Offline
Administrator
#2
Pass side fan should come on with gauge a little below half, and if temp still increases, driver side fan will come on with gauge around 3/4 of the way up.

Do the fuel and oil press gauges read normally? If they also read high, you have an IVR issue.

Do you have an IR thermometer to check the actual coolant temp at the radiator?

Possible gauge sender out of calibration or ECT out of calibration.

Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
Reply

Jeff K Offline
Administrator
#3
Another thought...... ECT may be reading too low a coolant temp due to the small coolant passage in the center of the lower intake being totally or partly plugged restricting coolant flow over the ECT. Pull the small hose off the bung in the lower intake that points toward the driver side firewall and poke a stiff wire (coat hanger, etc) into the bung and see if it is plugged or partly plugged, and clean out any debris. This bung plugging up is a somewhat common issue, especially if the coolant maintenance was neglected in the past.
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
Reply

Rob H Offline
Member
#4
Thanks for the quick answers Jeff, definitely don't want to be driving this thing if it's too hot. It just so happens that I just got an infrared thermometer from Amazon yesterday! The oil pressure and fuel gauges seem to work just fine.
I'll see if I can check that stuff later on tonight or tomorrow and I'll get back to you.
Reply

Rob H Offline
Member
#5
Ps
I've never used an infrared thermostat. I get that you just pointed at whatever you want to read the temperature of, would I assume correctly that I would need to point it at the fins or cap or any part of the radiator?
Reply

anasazi4st Offline
Senior Member
#6
When I replaced the head gasket in 2013 I thought it would be a good idea to also replace a lot of the little stuff that’s pretty much inaccessible when the intake manifold is in place. Various coolant hoses, the oil pressure sending unit...and the coolant sending unit, a little brass fitting with a single wire lead.

When I took the car out for a test drive with the new head gasket the temp gauge quickly moved to the very top and stayed there. Panicking, I drive home on back streets at 15-20 miles per hour. The temperature outside that day was about average for that time of year (mid-August), about 100 or so, so it wasn’t extremely hot.

When I got home I checked the engine and it did not feel particularly hot. The radiator cap was warm to the touch and I was able to remove it with no boiling over or coolant loss.

I got under the car and replaced the sending unit with the original OEM one. PROBLEM SOLVED! Temp Gauge went back down to just above the first mark. Even now sometimes it will get halfway up but rarely ever above it. I run the a/c constantly and frequently the second cooling fan comes on and stays on, but again that’s normal for this time of year (on cooler mornings—about 80-90 or so—only one is on, with the a/c).

I have never used an infrared thermostat on this car, so I can’t swear that the temps that day weren’t accurate. But, as I said, it didn't seem to be on the verge of overheating—far from it.

After this I did some research and learned that there are several different sending units available. I purchased another one from Advance Auto that is supposed to be a direct replacement (but so was the other one from NAPA), and after it cools down a bit I’ll install and test it.

Maybe someone else can chime in and relate their experiences.
Another proud dues-paying member.

1987 Turbo Coupe w/T5OD, 8.8 axle, grey smoke; most options. Got it in 1991 with 41K miles: 3 turbos, 2 heater cores, 1 T5OD full rebuild, 5 clutches, 1 head gasket, 2 Teves II ABS units, etc. later....
Reply

gtbird Offline
Member
#7
I have this radiator cap as a second source to monitor www.holley.com/products/cooling/radiators_and_accessories/radiator_caps/parts/2471S
1988 T/C Silver with red interior, fully loaded except for leather. 5 lug conversion with 97 Cobra wheels, Cobra 13" brakes up front, Mustang brakes out back, Koni adjustable shocks and struts, NOS Koni lowering springs . Maximum Motorsports control arms and caster/camber plates, subframe connectors.
Reply

Rob H Offline
Member
#8
That's pretty cool. I didn't get a chance to do anything with the car today but I did go for a run and brought my infrared thermometer with me.
Of course it behaved today.
Still always on the higher end of normal but nowhere near as high as the other day
Reply





Users browsing this thread:
1 Guest(s)



Theme © iAndrew 2018 - Software MyBB