Oil Temp send unit

Hi, All! Where is the proper location for the temp sending unit?
My car has the temp sender on a brass "tee" behind the fuel pump along
with the pressure sender. Am I getting accurate temp reading at this location. Reads sort of hot in my opinion while driving.
Thanx, all!

Bill, This topic has no right or wrong answer. There are different locations that the sending unit has been mounted in VW engines. The important element is that you determine, independently, what your gauge is telling you. A solution that works is to buy/beg/steal from your kitchen a meat thermometer long enough to contact the oil in the dipstick tube. Check the thermometer temp at various gauge settings, e.g., gauge barely off the peg, halfway, 3/4, etc. In that way, you will know how your specific gauge actually reads. Some manufacturers, such as Berg, won't even sell gauges, including VDO, since they believe the inherent unreliability gives one a false sense of security. The real value of a gauge is one of relativity--you will know where your gauge should sit for proper operating temp., especially after you measure it independently. If it goes beyond the normal setting, shut down quickly and investigate. Regards, Jim

How hot is "sort of hot"? When the oil is presurized the temp goes up slightly, and that sensor location precedes the oil cooler. If the oil in your sump stays below 220 F at highway cruising speeds on hot days you probably have nothing to worry about. If you don't have a meat thermometer pick one up at the local grocery store or kitchen specialty shop; longer is better as the short ones just barely reach the oil in the sump at spec oil level.

Thanx for the info guys. I guess the main question was should the gauge read sump temps or the temps before the cooler like George said.My vdo combination gauge set was reading towards the upper end of the scale as
close as 3/16" until the red area.Anywho it's off to the grocery store
or walmart for a thermometer.
Thanx,
Bill D.

I'm not all that crazy about temperature pick-ups at the bottom of the sump. I added a 1 1/2 quart sumpt to my motor and the temperature gauge went way down (it now reads at about 1/4 of the way across the gauge. I know it's running hotter than that because I have an external cooler with a170 degree cut-in switich which cuts in way before the gauge gets close to the 1/2 mark. I've used a cooking thermometer and it usually reads 160 to 170 degrees when my gauge reads between 1/4 and 1/2. My problem is that I'm running a 911 style cooling shroud (I know, I know it's too much cooling) with a mild 1776 motor. I really need a 2300 + monster motor to match the 911 cooling.

Oh boy. Bolt on sumps may have unusual characteristics in terms of oil temps ("cool pockets"). For instance, oil on the inner sump surface may cool and form a "boundary layer" that kinda/sorta acts like insulation between hotter oil and the sump casting. And oil in the corners of the sump may tend to stay there. A sender in the sump may fall victim to both this boundary layer and the aluminum sump temp and read a bit cooler than expected (do not use sealing tape on the sender threads).

The hottest oil is normally a thin film on top in the sump, but then again oil in the sump gets whipped around by crankshaft turbulence.

My sump sender didn't read accurately so I got one of the VDO senders that replaces the dipstick (takes the normal sender lead but also requires a separate ground lead). On a really hot day, say 90 F ambient temp, cruising at 70 mph (3,250 RPM) my oil temp will get up to about 215 F (checked with accurate meat themometer) which is about 3/16" to 1/4" down from the red zone on the bar gauge.

No need to worry about 215 F oil temp, epecially if it's synthetic oil.