Engine temperature

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Paul Kupferberg
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Engine temperature

#1 Post by Paul Kupferberg »

After owning and driving my 356 C 1964 cabrio for 28 years one would think I should know the answer to this. How high is permissable on the engine temp gauge. After about 45 minutes of driving my gauge is fully to the right into the white box of the vdo gauge and I am concerned that it is running too hot. I have never attempted to calibrate the thermostat. Advice eagerly sought and thank you in advance.
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John Brooks
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Re: Engine temperature

#2 Post by John Brooks »

It's should smell hot, if the oil is that hot. Probably a bad sender or a mouse has moved into the fan schoud. I would replace the sender first. If the gauge was bad it would be bad all the time.
John Brooks

62 Roadster
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getting pushed around in porsches since 1965

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Doug McDonnell
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Re: Engine temperature

#3 Post by Doug McDonnell »

Or a cooler that is mostly blocked from decades of stuff. Buy an inexpensive temp reader to see what temp your engine really is. Needle in middle is usually somewhere around 180-200 depending on calibration. I use the rule of thumb I used when I had a 911 220 degrees is hot and 240 degrees is too D#*N Hot!
1965 356C 2000 BMW 740i Sport 1967 Honda CL77 There is never enough time to do it right, but always enough time to do it over.

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David Jones
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Re: Engine temperature

#4 Post by David Jones »

Can you pull the dipstick when it reads that hot. If you can then it is not too hot. Buy a cheap IR gun or get a kitchen thermometer with a long stem. I have a 12" fry thermometer as well as the IR gun so I can read the oil temp direct when I place it in the dipstick tube. They are only about $5. Check it by placing it in a pan of boiling water and check your IR gun at the same time. Total cost for both may be $20.
One point of information is that you do not have a thermostat all you have is a temp indicator. A thermostat regulates temperature and your gauge only displays it. Being a mechanical device it is subject to variations due to age and failure.
All that being said do check for debris in the fan housing. With engine off reach in behind the fan and feel for debris in the vanes or take a picture and see what you have. Luckily you have the later fan housing without the guard so easier to inspect.
If I had known I would live this long I would have pushed the envelope a little harder.
Cymru am byth
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Charles H Jacobus
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Re: Engine temperature

#5 Post by Charles H Jacobus »

When I first got my car a couple months ago the reading was in the 1/3 range. Then it jumped to 3/4 stayed there for 10 seconds, then jumped back to 1/3. I knew it was an electronic issue because it jumped so I wiggled the gauge wire. It jumped back to 3/4. I used an IR temp gun 4"s and then 1" from the sender unit. It read 160. I haven't figured out the problem with the gauge yet, but that's were I'm going.

ChuckJ
Current:
2012 Silver 991
1995 Midnight blue 993
1965 Red 356C

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Fond memories of 14 others (including a '63 Normal and a 61 S90) :)

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Walt Nolte
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Re: Engine temperature

#6 Post by Walt Nolte »

One of our vendors, I forgot which one, sells these. Helpful in comparing temp to the gauge reading.

Walt Nolte
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Wes Bender
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Re: Engine temperature

#7 Post by Wes Bender »

Precision Matters has them. http://www.precisionmatters.biz/356-dip ... ometer.php

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Wes
Some days it's just not worth chewing through the restraints.....

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Charles H Jacobus
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Re: Engine temperature

#8 Post by Charles H Jacobus »

Doesn't the temp gauge reads after the cooler, making it cooler than the sump?

ChuckJ
Current:
2012 Silver 991
1995 Midnight blue 993
1965 Red 356C

Past:
Fond memories of 14 others (including a '63 Normal and a 61 S90) :)

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David Jones
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Re: Engine temperature

#9 Post by David Jones »

It does Chuck which is why I like to measure it at the oil pump with an IR gun to see the "real " temp but to check gauge reading against the IR gun that has to be done at the sensor.
For what it is worth I just measured my oil temp after a quick drive on twisty roads where the oil temp got to just over two needle widths past the green and the oil sensor measure with an IR gun read 176 and so did the oil filter.
I did not measure the oil pump temp as I was only comparing oil temp gauge to IR gun.
If I had known I would live this long I would have pushed the envelope a little harder.
Cymru am byth
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Charles H Jacobus
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Re: Engine temperature

#10 Post by Charles H Jacobus »

Two needle widths past the green block on the left or right, David? Mine read 160 one inch from the sender unit after a long hot trip of 20 miles and the needle was at 3/4.

ChuckJ
Current:
2012 Silver 991
1995 Midnight blue 993
1965 Red 356C

Past:
Fond memories of 14 others (including a '63 Normal and a 61 S90) :)

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David Jones
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Re: Engine temperature

#11 Post by David Jones »

Past the green block on the left Chuck. If it ever got to the right of scale I would be worried unless I had calibrated the scale and knew that was OK.
If I had known I would live this long I would have pushed the envelope a little harder.
Cymru am byth
David Jones #9715

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