Oil temp from pressure point?

[joey]

Hey guys,
Looking to kill 2 bids with one stone and use a T-piece to connect my aftermarket oil pressure and temp gauge senders at the original oil pressure sender location. I have all the appropriate fittings to do this but my question is would the oil temp reading be accurate at this point?
From what i've read most people reccomend tapping a hole in the sump for the oil temp sender as apparently it gives a "true" reading of temp but i prefer not having to do that if it is the same at the oil pressure position.

Cheers, Joe

[privatealpha]

You can buy special sump screws that have a built in thermostat.
Cheapest way to do it, and no need to drill anything.

[dangdang]

Average oil temp will be the same at any point as it is being circulated flat stick...

Pulling the temp of the pressure gauge port is probably as accurate as anywhere else...

The idea of the temp on the return is that the pressurised oil is hotter...

[joey]

Ahhh ok makes sense i guess, i figured if people are using a sandwich plate to get the temp then i dont see why not from the pressure pickup. Just wanted to make sure.
Thanks guys

[GT1978]

Unless the temp sensor has a small probe that protudes into the oil flow, like that on a coolant sensor, it's more likely to just be reading the temp. of the block as apposed to the oil at the oil pressure connection point. Block temp.is likely to be higher as it sees the heat source directly and the oil and coolant absorb there heat from this. Measuring from the sump gives you a more acurate reading of what is happening temp. wise to the oil being circulated.

Glen

[oldcorollas]

A T piece off the block will be in static oil, and is also hanging in air, so the tep will nto be accurate.

sandwich plate works because oil is moving.

do you want to measure temp of oil coming out of the block or into the block or sump temp? all will be different

[joey]

Hmmm i see, and all valid points. The temp sensor does have a probe at the end but it would be sitting in "static" oil. Maybe a stupid question but would the oil sitting in the fitting not merge with the flowing oil and come up to the same temperature? This is the fitting i have in mind....

[banana_socks]

Oil is thicker than water, and doesn't have as good heat transfer properties, so its more likely that there will be temperature gradients in different parts. The pressure sender is effectively a dead end, so the oil there will stay there, and only be heated by the nearby oil flowing past. This means it will be colder than the average oil temp, and delayed to any sudden increases.

The tapped sump plugs look like a neat solution.

[mick08]

Thinking practically why not use one of those laser temp guns and check both the sump and the block where the fitting will be and see what the diff is after some 'spirited' driving, one thing is for sure you will want to know the hottest part of the oil, you don't want to be looking at a gauge thinking everything is sweet only to find the actual temp is much hotter,why do you need oil temp? is it a race car situation? If the car runs an auto why not put your temp gauge in there instead?

[joey]

Thanks for the info banana socks, sump it is!. Mick08 its being used in a drift car so it will get flogged pretty hard.

[cyberdiamond]

Just FYI I have found oil temp with the sender in the sump about 10c cooler than oil flowing in the system. This is just because of the air cooling effect of the sump.

Also if you put it in the sump make sure you wrap the sender well to stop the air rushing past cooling the sender and altering the reading (real world test confirmed).

[mick08]

I work on Volvo truck engines and they run an oil level and oil temp in the sump all in the one tube, i've never cracked one open but all i can see when i look down the tube is a PCboard and soldered joints, i also worked for Detroit where we also built Allison transmissions, they also put the temp sender probe in the sump area, just off the bottom. I can't remember if the Detroit engines ran an oil temp sender anywhere, All the books i have read on modifying GM autos for drag racing etc reccomend running the temp sender in the sump,I'd put it in the sump if i was you.

[abently]

Just FYI I have found oil temp with the sender in the sump about 10c cooler than oil flowing in the system. This is just because of the air cooling effect of the sump.

Also if you put it in the sump make sure you wrap the sender well to stop the air rushing past cooling the sender and altering the reading (real world test confirmed).

+1

Make sure you have and/or extend the factory belly pan.