I have a 91 chevy 305 TPI, I would like to install a VDo oil temp gauge. I am unsure as to where to install the OIL temp sensor for an accurate reading or which OIL temp sensor I need to purchase. Any advise would be greatly appreciated.

Thanks
Mike

 

An oil temp sender needs to be in the oil pan.

 

Can I replace the oil drain plug with the sensor? If i can install the sensor in place of the drain plug, any idea the thread size of the oil pan.

Thanks
Mike

 

The factory oil temp sender on Vettes is fitted in the oil gallery port above the oil filter so it shows the true temp of the oil in the engine

 

I didn't know vettes had an oil temp gauge, but then I haven't been around 'em much either.... LOL

Not saying it isn't a temp sending unit, but that sender sure looks like a oil pressure sending unit. Other than being shorter, the metal body part is the same shape, (socket wise), and the electrical plug in looks to be the same shape as an oil sending unit.
My 89 TPI 305, (Trans Am), has the oil pressure sender in that location but the sending unit itself is considerably longer.

 

Pic is of a 3rd Gen to show the location.Vettes have all the oil switches / senders behind the dist leaving
that port free for the oil temp sender

There have been a multitude of different style / configuration oil units for GM cars
http://www.motorcityreman.com/generalmotors14.html

FYI
81-89 1 wire oil temp unit
https://pontiworld.com.au/usgmsp/pro...388e04a895fe8f


90 -96 units have 3 wires for feedback to the ECM to calculate the "change oil " light

 

Ah, I see now.

I'd never seen that short style 3 wire press sending unit. Mine has the huge long one. But I see the short one came on the Berettas too, and it just so happens I have one of those sitting in the driveway getting ready to go to scrap. LOL I'll have to look at the sending unit in it before it leaves, just to test fit it in my truck. I need all the room I can get... LOL

Good info vetteoz.

 

I thought that was the oil pressure switch for the fuel pump.

Why would vettes have an oil temp sending unit? Does it tell the computer something, is there a gauge?

Not doubting you, I have no experience with vettes, just curious.

 

Yes

As noted above , on '90 + cars the ECM uses the oil temp as part of it's calculations for displaying the "Change Oil" light

As noted , always mounted behind the dist on C4's, not above the filter as done on 3rd Gens
Pre '88 cars had a separate pump switch and gauge sender; later cars had the large 3 wire combined unit shown

 

Thanks for the info! I never knew!

 

So for a firebird owner, could it be possible to put a T-fitting where the oil pressure sender is and also hook up the oil temp sender unit?

 

Anything is possible but you would get a more accurate temp reading with the sender directly into the flow of the oil gallery of the block ;
not standing outboard in the breeze ( cooling off ) on a T fitting

 

Go to the hardware store and get some 1/8 npt fittings.

 

This is a good point haha, one more thing since vettes have the oil pressure switch mounted on the back of the block near the distributor, what does that port do for f-body applications? or is it just blocked off?

 

MY GTA has the oil pressure sender behind the distributor. When I changed my motor mounts I knocked the wire off getting the motor high enough and my gauge quit working.

 

Hmmm thats interesting because on my Formula the oil pressure sender is located just above the oil filter

 

I do have the oil cooler (warmer) on my car so maybe that has something to do with it.

I should also add mine just has one wire with a spade connector. If I remember correctly I think the wire was orange.

 

Hmmm maybe because its a GTA and they had more options

 

Dont know but I do have a digital dash if that means anything.

 

Yeah probably, since the vettes had digital dashes they used oil temp to let the computer know when to flash the "change the oil" light on the dash

 

Only for '90 +
The all C4's had a standalone oil temp gauge as I noted above

 

I think what we are getting out of this is we have 2 places to tap in for oil pressure or temp.

I know all the earlier SBC pulled the pressure from behind the distributor like my 87 is.

You can use a T for pressure and put your temp in the other place. Just don't block the passage off by putting it to deep!!

 

My '85 GTA with a 350 swapped for the original 305 has the oil pressure sender (single spade connector) behind the distributor going to the rally gauges. I'm not sure if there is an oil temp sender or where that signal would go on my car. I replaced the oil pressure sender when I bought the car and the dash gauge magically started working. Simplest fix I've done so far.

Side note, the rally temperature gauge goes to the cylinder head temp sender on the block (forward driver's side) above the exhaust manifold. Look for the cracked/melted (green?) wire.

Now I'm curious if I have another disconnected sensor hiding somewhere... The block temp seems to get warm on those summer hauls up out of the 120* heat of Phoenix with the A/C going full blast to stay alive. I've been contemplating adding an oil cooler to help her beat the heat on the highway. Knowing the oil temp would be useful and feed my OCD need to know exactly what my engine is doing at all times.

 

I ended up installing the sensor in the oil pan and it works perfectly
Thanks
Mike

 

Older post, but could you throw up a picture of where you installed it? or did you just install it in the oil plug location?

 

Here's how I did it. Mech gauge btw


https://photos.app.goo.gl/tpxoWTbEsRTkCs0H3

 

Hey Twin_Turbo. I am going to put in a mech. oil temp gauge in my bird. Its an Autometer. The tube that looks bolted to your oil pan, looks like a white plastic seal...where did you get that please? thanks

 

Regular replacement oil drain washer seal

 

NICE Thanks for getting back to me. Thats what I will to. But what is the part coming out of the pan please? Looks like a metal drain neck (for lack of a better description on my part)

 

I fabbed it myself.