Correct Oil Temp.....?

joetiii · joetiii's Garage

So I replaced my old colored oil temp gauge with a new numbered gauge and the correct corresponding sending unit.

I have driven the car in the cool NE temps (35-50 degrees) a few times now and I question if the gauge is accurate. It takes about 5 minutes for the needle to move and then it gets up to about half way from 120 to 180 degrees. Doesn't matter if I run the car at 3800 RPM down the highway, or idling at a light. Is this normal?

What temp should the engine be running at?

Should I be concerned?

Hladun · 03-29-2007, 01:58 PM

Sounds about right at cold ambients. Does your front loop stay cold?

joetiii · joetiii's Garage

Quote:

Originally posted by Hladun
Sounds about right at cold ambients. Does your front loop stay cold?

Sorry... I don't have a front loop. That's next.

I can say that last year in the heat of summer, the colored gauge never read past half way. not that I ran it hard in the heat, but it does appear to run pretty cool with just the stock rear cooler.

Here's something new I just noticed on the ride home. The oil pressure gauge reads just fine up to 3000 RPM, Then it starts bouncing aroun from 3K +

Is this a resistance issue around the sender?

NY65912 · 03-29-2007, 03:11 PM

I too changed out my temp gauge on my SC to the numbered one.

I'm still not sure if I'm getting an accurate reading, the temps seem low.

the · 03-29-2007, 03:18 PM

If you're saying your car's normal operating temp when fully warmed up is 150 degrees when driving in 30-50 degree temperatures, I think something is wrong with your car. Maybe the thermostat is stuck open? Gauge is inaccurate?

150 is too low and isn't good for your car, you are driving it around without it ever getting fully warmed up to the normal or optimal operating temp.

DanielDudley · 03-29-2007, 04:03 PM

Some one correct me, but isn't the sender for a numbered gauge different from the sender for a non-numbered gauge ? Seems like I read that somewhere.

Formerly Steve Wilkinson · 03-29-2007, 04:58 PM

Yes, different senders.

deanp · 03-29-2007, 05:09 PM

He indicated in his first post he changed the gauge and corresponding sending unit.

THe best way to check at this point is to pick up an infrared thermostat, aim it different spots on the motor, the base of the sending unit the soft hose from the tank etc. This will give you a good idea of the oil temps so you can be sure whether or not the oil temp is correct.

If in central MA I can lend a hand.

DW SD · 03-29-2007, 05:10 PM

Guys,
Take the sender out and put it in a pot of boiling water to calibrate.

Look for 212 on your gauge.

As an alternate, buy a long digital thermometer (I bought a 12" one) from Mcmaster.com ~ $40 and put it in the oil tank. Your oil temp sender measures at a different location, but there definitely is a strong correlation.

Doug

Gogar · 03-29-2007, 08:45 PM

Well, look for 212 in taxachussets. At 7000 feet, where I used to live, look for 196F. In denver, about 202.. Science is fun.

joetiii · joetiii's Garage

Quote:

Originally posted by deanp

THe best way to check at this point is to pick up an infrared thermostat, aim it different spots on the motor, the base of the sending unit the soft hose from the tank etc. This will give you a good idea of the oil temps so you can be sure whether or not the oil temp is correct.

If in central MA I can lend a hand.

I'm thinking about trying the infrared thermo or boiling water route to test the gauge / sending unit accuracy.

My wife and I are planning a trip to Sturbridge this saturday, but we'll be driving the minivan.

Should I be driving the car at such low oil temps?

Also, whats up with the oil pressure gauge bouncing all over the place at 3k+ RPMs.?

Formerly Steve Wilkinson · 03-30-2007, 03:50 AM

The actual temperature of the oil in the engine hasn't suddenly and mysteriously changed because you put a new gauge in the panel. The oil is the same. The reading is different.

wowzer911 · 03-30-2007, 04:00 AM

I don't think 150 is too low, mine runs about that temp in 30-50 deg. ambient temps., unless I run it pretty hard. It only hits about 180 in the summer time heat, but I do have a front cooler.

Bill Verburg · Bill Verburg's Garage

W/o a front cooler there is one t-stat that opens @ ~180&deg.

Below that temp the oil is circulated internally only. Above that the oil is directed to the engine mounted cooler.

During cool weather the temp will stay at ~180

nixtfy · nixtfy's Garage

My normal operating temperature is 180 after ten minutes of running in almost all temperature conditons on my 78 sc. The highest I ever see is 210. I have turbetol cooloer in front.

wowzer911 · 04-01-2007, 07:28 AM

Well, ambient temperatures seem to have a large effect on mine. In 30 deg. temps I can easily run 20 miles before it gets up to 180, and my front cooler rarely kicks in unless I'm driving aggressively. In summer temps. it hits 180 deg. very fast, and I can literally tell by the gauge when the front cooler kicks in and controls the temp. I also always warm up the engine in the driveway before taking off no matter what the temp outside. Of course the oil one selects for the time of year plays an important part as well.

Bill Verburg · Bill Verburg's Garage

Cars w/ a front cooler have 2 t-stats that open at roughly the same temp, but there is a lag for the second one opening. On those cars there will be 2 plateaus the first ~180&degF the second closer to ~200&deg. Ambient and driving conditions affect where the gauge temp will stabilize(if it does at all)

wowzer911 · 04-01-2007, 08:43 AM

The point I'm trying to make is that when freezing cold air is blowing across the motor, it can take much longer to reach optimim operating temperature.

joetiii · joetiii's Garage

Well I was out for a good 45 minute run today (ambient temp 50 degrees) and the engine temps climbed up to 180. I could sense when the T stat for the engine cooler opened when the temp dropped down to 160 or so.