Author Topic: Help needed, from all of you!  (Read 5929 times)

alpina

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Help needed, from all of you!
« on: July 04, 2017, 22:29:20 »
I need your help. I have asked this in the past. Promises were made only to hear nothing.
So I am making the call out to everyone who has access to a infrared temperature gun to take some readings at the engine when it is at it 'normal' operating temperature.

1. Top of radiator / top hose
2. Thermostat housing
3. Temp gauge pick up  (pod or take off between plugs 5 & 6)
4. The head front to back near plugs.
5. Note the position of the needle on the gauge in the car when taking the readings.

If enough of us can do this it should give us a good temp profile of the engine.
This would help any one know for sure if they are running hot and if the gauge is
Reading correctly.

I have thoroughly searched all past posts relating too temps, there is one post asking
If his readings were normal, he received no replies.
So again I am asking for your collective help in this. I have in the recent past helped numerous members here with decals, data cards among other things, so now I'm asking
This one simple favour in return.

Living in Asturias northern Spain I have little chance of finding another pagoda owner to carry out the experiment. I have never seen another since I've been here.
If there is no response, maybe this could be done at this year PUB ?

So the next time you return from a drive, and you have a IR temp gun, you know what you should do, it only takes a couple of minutes.

Thanks in advance.

DM




Paul & Dolly

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Re: Help needed, from all of you!
« Reply #1 on: July 05, 2017, 13:55:54 »
Hi Alpinaltd ?

As we have "Spanish" weather today in Wales, 24 deg C, I thought I would help you with some temperatures, after we came home from a short trip in the hills.
Ambient Temp 24, Engine idling after trip.

1 Radiator Top  81  Top Hose  70   (different materials affect an I/R Thermometer)
2 Thermostat Housing  81
3 Temp. Gauge Pick up  87
4 Head from 1-6 near plugs .... 80  85  86  89  86  84  (Difficult to get steady readings here though)
5 Gauge Needle    Just above 180 deg F  maybe 185 deg F.....(85 deg C )

I hope this is of help for you

Keep Cool

Paul
Paul (located in Cardiff - Wales - UK)
1967 Early 250 SL (Auto) White
Mitsubishi i Car
Toyota RAV 4  Hybrid AWD
1936 Alvis Firebird (Gone............)

alpina

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Re: Help needed, from all of you!
« Reply #2 on: July 05, 2017, 15:23:53 »
Hi Paul,

Thank you for taking the time to do this. This is great start.  It also points me in the direction that my
gauge reads high. Yesterday ambient temps here were similar to yours (considerably hotter in direct sun 35c).
Took a 200km trip, mainly through country mountain roads. Going up / round mountain roads the gauge would creep up to
Touch the very bottom of the next white square above the 80c mark. Coming down hill the gauge would lower to midway
Between 80c and the square above. Sitting at traffic lights in direct sun the gauge would again touch the white square above
The 80c.
On returning home I once again took readings. The gauge at this stage was sitting midway between 80c and the next white square.
(I guess this would be 90 – 92C on the gauge)
My IR temp readings at the points mentioned, range from 72 deg C – 78 deg C

As you can see, quite different from the gauge. I know I can test the sender in boiling water to see where the gauge reads.
but knowing my luck, I would break the tube and give myself more trouble.

I think this an interesting experiment that should help many who think they are running hot… There is a chance it could be the
gauge. I would note that my car does not have the original deg F. temp gauge. it was replaced for deg C. in 2007 by previous owner.
Whether this is a factor is anyone’s guess.

So the more readings we can get the better picture I will have, and some reassurance that the my actual engine temp is ‘normal’..

Thank you again, this is much appreciated.

Best regards

DM

Paul & Dolly

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Re: Help needed, from all of you!
« Reply #3 on: July 05, 2017, 22:21:15 »
Hi Alpinaltd

The problem with IR temp readers is that different materials, and colours reflect the IR differently, you can adjust some for emissivity and other variables, but this still makes it difficult to obtain accurate readings.
We used to mark standard measuring points with a standard paint or tape to try and elimate these variables.
I have prevoiusly use contact digital thermometers for other investigations, on previous cars.

What readings did you get for the positions you requested ?

I find it difficult to understand the divisions on the Pagoda gauge, but generally mine runs around 180 F mark, +/- 1 mm or so.

Stay cool

Paul
Paul (located in Cardiff - Wales - UK)
1967 Early 250 SL (Auto) White
Mitsubishi i Car
Toyota RAV 4  Hybrid AWD
1936 Alvis Firebird (Gone............)

alpina

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Re: Help needed, from all of you!
« Reply #4 on: July 05, 2017, 23:32:47 »
Hi Paul,
My readings are below. I understand that emissivity set on the IR gun was to read correctly from a
preferably Matt black surface, okay for the radiator, top hose, and pick up on the pod.
I did not change the settings for the readings on lighter grey head.
I also have a temp probe inserted in the radiator fins near the top hose for a digital thermatic switch
And this reads 70C.

1. Top of radiator  73C / top hose 71C
2. Thermostat housing  76C.  (I have 79C thermostat)
3. Temp gauge pick up  (pod) 76C
4. The head front to back near plugs. 72C 72C 73C 74C 71C 72C
5. position of the needle on the gauge in the car when taking the readings. Approx Midway between 80c and next white square so about 90-93C

Thanks again. DM.






MikeL43

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Re: Help needed, from all of you!
« Reply #5 on: July 06, 2017, 19:41:22 »
Have you checked the temperature listed for your radiator thermostat?  I just replaced an 87 degree C thermostat with a 73 degree C thermostat and immediately reduced the temperature indicated on the dash instrument to the upper middle of the center mark on the dash instrument (about 15 degrees F),  We use Fahrenheit here and I believe the old thermostat was around 185 to 190 degrees F and the new one was a little less than 175 degrees F.   I researched the recommended temperatures on the forum, take a look, there is a lot of discussion concerning this issue and decided that the lower temperature one was best for me as I live in Florida, USA.

alpina

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Re: Help needed, from all of you!
« Reply #6 on: July 06, 2017, 20:17:03 »
Hi Mike,
As mentioned above I am using a 79C thermostat. This would seem to correspond with the IR reading
At the Thermostat housing of  76C.
I my case the temp readings taken with a IR temp gun are around 15C lower that what the gauge on the
Dash reads.  Maybe I will try a 73c thermostat  when the coolant is changed. But I am pretty much convinced that the engine temps are fine, only the dash gauge reads high.
If we could get some more readings this would help.
Best regards DM.

peterm

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Re: Help needed, from all of you!
« Reply #7 on: July 07, 2017, 15:41:42 »
I had an awful cooling issue and my gauge would often venture to red when in traffic or stopped,  forget about putting on ac.  I tried all cures-removed fan shroud- water pump- fan clutch- radiator flush-water wetter- new thermostat- nothing seemed to work I was ready to pull the ac and put in accessory electric fans when fortunately my mechanic was doing some unrelated work and while transporting to a sub in the rain, rear ended a jetta- 27 k later I had a new front clip- radiator/ ac condensor/ water pump - fan and no longer is cooling an issue

perhaps though not the best way to solve the issue   ( the new 4700$ grill and bumpers are really nice and saved me on rechroming)

waltklatt

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Re: Help needed, from all of you!
« Reply #8 on: July 07, 2017, 17:36:13 »
Ouch!
So, PeterM, what really was the issue?
Surely a complete new front end is not the solution.
Was it the radiator or condensor that was blocked up?
Walter

alpina

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Re: Help needed, from all of you!
« Reply #9 on: July 08, 2017, 09:22:49 »
Okay chaps, let’s get back on track. It’s the weekend, so many of us will be enjoying
Our cars. Just remember if you can take some engine temp readings with an IR temp gun
Please do and report here. The more people the better.
Thanks, DM.

alpina

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Re: Help needed, from all of you!
« Reply #10 on: July 17, 2017, 13:56:37 »
I give up.

mrfatboy

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Re: Help needed, from all of you!
« Reply #11 on: July 19, 2017, 01:20:26 »
I give up.

Don't give up😀😀😀

I would have posted sooner but I have been reupholstering my seats and just got the drivers seat in a couple of days ago and just bought the IR heat temp gun ($5 harbor freight sale😀)


San Diego day 83 F.   IR temps had ranges but I used high average temp. See photo for gauge temp.


These temps in Celsius

Rad Hose 68
Radiator 76
Themostat housing 86
Temp gauge pick up 82

Between plugs front to back
71
81
81
55
79
79


Let me know if I can remeasure anything else.   Also,  I can probably test a couple of other cars in a month(the volunteers can guess who they are😀)


P.S.
It might be good to post a pic of the engine bay with exact locations on where to measure temps so everybody can make sure they are measuring same locations.
« Last Edit: July 19, 2017, 05:04:12 by mrfatboy »
1969 280sl (Aug 1968 build)
Signal Red
4 Speed

kampala

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Re: Help needed, from all of you!
« Reply #12 on: July 19, 2017, 02:30:25 »
Don't own an infrared meter, but borrowed my neighbors very expensive snap-on this evening.     (saw your "I give up" and trying to help)

The temp readings fluctuated a lot. I picked the one that came up most often. 

My car gauge is Fahrenheit.  Car was driven for about one hour.

Outside temp was about 26c / 79f

See photo for car gauge - Just above 180 (probably 190 based on having a 87c thermo and with this thermo, the temp stays here, with a lower thermo, it drops)

1. Top of radiator  82C
2. Thermostat housing  84C.
3. Temp gauge pick up  83C
4. The head front to back near plugs. front 77C  middle 79C back 80C
5. Note the position of the needle on the gauge - 188-190F (87c-88c)  (see photo)

Good luck.


250sl - later - manual
280sl - 1971 - Auto - LSD

alpina

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Re: Help needed, from all of you!
« Reply #13 on: July 19, 2017, 19:26:35 »
Thanks chaps. I knew I should have held faith with you guys a little longer.
My latest experiment was to install a digital thermometer with a k type thermocouple
attached (with thermo paste) the too the temp pick on the ‘pod’. The digital readout was hidden
In the ashtray. Now I can monitor the surface temp of the pick-up. The Thermocouple reacts very
Quickly to temp changes.

From the readings given by you guys so far at the temp pick up (87C, 83C, 82C) all show or say the gauge reads
Just above 180F or 80C. (approx. 85C or 185F)

In my particular case a 76C IR reading at the temp pick up, the gauge needle would be horizontal midway between
80C and 100C(next white square) so approx. 90C.

Readings taken with the digital thermocouple while driving (different day); show temps ranging from 155F – 175F.
when the gauge read 175F The car was idling in the garage after a 2hr drive this is the highest temp I saw. The dash
gauge at this point was sitting touching the bottom of the higher white square.

Therefore I conclude that even allowing for the heat transfer  (water temp – surface temp) my particular gauge
Reads high, approx. 15 deg C. and my engine temps are on a par with the readings given here, if not mine are slightly
Lower.
So now I feel more comfortable that things are ‘normal’.

More readings always welcome. Thanks Paul, Aslam & ‘mrfatboy’.

All the best

DM

alpina

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Re: Help needed, from all of you!
« Reply #14 on: July 21, 2017, 21:50:40 »
Another clue that my gauge reads high. Car has been sitting for the past week in the
Garage not started or driven. IR temp gun shows the engine at 22C. Thermocouples/
Digital gauge shows the same. Yet the dash gauge is off its stop and above the 40C
Marker.