new oil temp readings problem

[tizzfishin]

I installed a fined oil sump and vdo oil temp sender. When I turn the key on it raises to 120 but only goes slightly over 120 after a 30+ min drive. Any ideas? bad sensor? or electrical? I used the same wire that I had on my old set up using the T-adapter with the pressure and dummy light. On the same drive my temp would be 180-200 at the T location. Engine is 1600 dp with all cooling tins. Thanks
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1971 westy


"An idea that is developed and put into action is more important than an idea that exists only as an idea"

[Wildthings]

How about a picture showing your oil temperature sender mounting?

[Tcash]

You need the VDO gauge for that sender.
Ohm test the sender. Resistance should change as sensor is heated up.
Run test wire from sender to gauge, To rule out the wire.

Good Luck
Tcash

[richparker]

So he installed a 1.5 QT deep sump with a VDO sender in the drain plug hole of the sump plate. That's what I'm getting from the post.

I'd say your temputure is only around 120* because the sending unit is in the wrong place. I have used an IR gun pretty extensively on my engine, where I too have a VDO oil temp guage and a 1.5 at deep sump. The drain plug is always quite a bit cooler the actual engine. So your sender is reading the oil temp at the bottom of the sump which is far from the engine and hanging down getting extra cooling. The sender should be machined into the case.

I would buy an IR gun, HD has them for $30 and test the temp of the sender. If the gun matches the gauge then you know it's right and can start trending temps.
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[Vince Waldon]

...and if that sender is installed in a tee with the oil pressure switch or gauge (another possible interpretation of the wording) that's not a great spot either, since there's no flow past the sensor.

All that said... a picture of your installed sender and your gauge would be most helpful, as posted above.
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Vince Waldon Edmonton Alberta CANADA
1970 baywindow

[Greg in GA]

[richparker]

Gotta love when someone starts a thread then doesn't repost answering questions that were asked to try and help them...

I drove for 30 min this morning to work. When I got there my oil temp was 170* on my temp guage. I shot the IR gun at the sender and confirmed that it was indeed 170*. Then I shot the drain plug with the IR gun and it was at 120*.
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[Wildthings]

[aeromech]

My thought was a bad ground to the temp bulb. If he has a deep sump it may be electrically isolated from the engine because of the gaskets. A guy could run a separate ground wire straight to the bulb and see what happens with the gauge.
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[richparker]

^^True but my IR findings show 120* would be an accurate measurement of the temp "if" the sender is located in the sump plate.
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[SGKent]

My vote is with Gary because a bad ground will do that on the VDO temp senders. He needs to add a ground. If adding a ground fails then he has the wrong sender for that temperature gauge.

If he ever comes back to the thread he can post the sender part number and the gauge range, that should confirm if it is the correct sender or not.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[tizzfishin]

Thanks for all the replies. After a 25 minute drive home today in 90+ degree weather I used my IR on the sump plate and it read 137. You guys were right its a bad location for a temp sender. Especially with a 1.5qt sump. I moved the wire back to the original sensor and will stick with that for now. At least I can monitor extremes off the T- setup... Anyone want to buy a oil temp drain plug and off set sump plate?
_________________
1971 westy


"An idea that is developed and put into action is more important than an idea that exists only as an idea"

[SGKent]

you have to decide what is important to you. Oil exists everywhere in your engine and each of those places has a different temperature. Do you want to know what the temp is as it drains off the heads and piston bottoms, or before the pickup takes it on another trip? The sump temp is the temperature of the oil in the pool - not the temperature of the oil returning to the pool. It will make a trip thru the oil cooler too then warm back up in the case. Someone who wants to know the temperature of the oil returning to the pool would tell you that the sender is in a bad place, but someone who wants to know the temperature of the pool would say what a great place. If your gauge read 137F and your IR read 137F then there is harmony.
_________________
“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[aeromech]

Maybe this doesn't mean shit but with turbine engines they monitor the oil temperature going to the bearings.
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[Wildthings]

[tizzfishin]

[Wildthings]

I agree that it looks like a good idea. Maybe without the deep sump it would work better as the oil might be more stirred up. Or maybe with the alternate style pickup screen CIP1 also sells. Don't know.

[richparker]

I would leave it where it is since you already have it installed and its working. Just figure the actual temp is around 50* or so hotter. You also have an IR gun so you could check it if necessary.

Here is where my sender is located.

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[SGKent]

I used a low profile sump in my 1971 and it solved the oil temp issue on long hot grades in summer. You really need to live in California or Arizona to understand that. At 4,000 - 6,000' a grade doesn't do to an engine what 200' to 2200' does.

Like I said - all one need do is decide what oil you want to monitor the temperature of. A one mile grade at 90F doesn't blip the needle. A 30 mile climb will. Without the extra oil that 30 mile climb will require at least one pull over to cool, maybe 2.
_________________
“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[Vince Waldon]