1957 Oil pressure light on

[Koya]

Getting familiar with this T-Bird; the oil pressure light is on. Could use some help identifying the location of the pressure sending unit and the color of the wire attached to it. Also, there is a sending unit on the driver side of the engine close to the steering box. What is that for and what color wire suppose to attached to it?

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[biddle]

Getting familiar with this T-Bird; the oil pressure light is on. Could use some help identifying the location of the pressure sending unit and the color of the wire attached to it. Also, there is a sending unit on the driver side of the engine close to the steering box. What is that for and what color wire suppose to attached to it?

 

[Koya]

My apologies; it's a 1957 thunderbird with the 312 automatic trans.

 

[doug7740]

The oil pressure sending unit is located on the left side of the engine just below the drain valve. Refer to photo #2 from the attached pages of the Thunderbird Restorations Details & Specifications Manual.

doug7740
1955 Thunderbird Blue

 

[Koya]

Thank you! I took that for a water temp sending unit. there is a sending unit just below the throttle linkage. What is that for?

 

[doug7740]

The sending unit that is on the left cylinder head under the throttle linkage is the coolant temperature sending unit.

doug7740
1955 Thunderbird Blue

 

[CSPIDY]

The low oil pressure light is looking for a ground to complete the circuit and turn the light on. The sending unit could be shorted internally, you could have a short to ground in the wire from the light to the sending unit, and don’t forget you could have low oil pressure.

 

[Koya]

Thank you again for the prompt reply. I took the car out of the garage this morning to get it ready for dinner tonight. I let it idle, after a minute I noticed some oil under the car. I didn't notice anything from the valve cover or from the pan gasket. I rub my finger around the sending unit, I got some oil. So I replaced it one I got from NAPA. All is well, the light is off and no leak.

 

[jack-in-sac]

Getting familiar with this T-Bird; the oil pressure light is on. Could use some help identifying the location of the pressure sending unit and the color of the wire attached to it. Also, there is a sending unit on the driver side of the engine close to the steering box. What is that for and what color wire suppose to attached to it?

I f you look at your shop manual it should show you the location on the side of the engine block.

 

[Ward 57]

The oil pressure sending unit is located on the left side of the engine just below the drain valve. Refer to photo #2 from the attached pages of the Thunderbird Restorations Details & Specifications Manual.

doug7740
1955 Thunderbird Blue

Just where is the drain & sending unit. I crawled under and don't see the unit or the wire to trace it. I thought it would be near the pump. I think it's leaking as there are no oil leaks from the top.

 

[doug7740]

As I said before, the oil pressure sending unit is located on the left side of the engine just below the drain valve. When the engine was built at the factory they used 4 separate drain valves in the block (2 on each side) so you could drain and flush the coolant from the block. Unless you wanted the engine to be Concours correct, most people replaced the drain valves with drain plugs.

Attached is a picture of the left side of the engine I was rebuilding that shows the drain plug and the oil pressure switch.


doug7740
1955 Thunderbird Blue

 

[Ward 57]

As I said before, the oil pressure sending unit is located on the left side of the engine just below the drain valve. When the engine was built at the factory they used 4 separate drain valves in the block (2 on each side) so you could drain and flush the coolant from the block. Unless you wanted the engine to be Concours correct, most people replaced the drain valves with drain plugs.

Attached is a picture of the left side of the engine I was rebuilding that shows the drain plug and the oil pressure switch.

View attachment 10592
doug7740
1955 Thunderbird Blue

Thanks. I was so close. Got the bird up on jack stands and just need to jack it up further and turn out the wheel to get a better look. Later in the spring I need to go to a car wash and blast the undercarriage. Just found my E brake cables are seized up and need to trace that problem down too.

 

[Ward 57]

Well, I finally got underneath enough to find the switch. The drain and hole for the switch both have plugs and the switch is right next to the oil pump. The switch is dry but the pump has oil all over it. Is it difficult to rebuild or regasket the pump? do I have to pull the pan to remove the feeder tube or can it be left in place?

 

[Kjm]

My 56 did the same thing.
sending unit was bad, check to see if it has oil leaking out of the sending unit.
it s a cheap easy repair also.

 

[Ward 57]

My 56 did the same thing.
sending unit was bad, check to see if it has oil leaking out of the sending unit.
it s a cheap easy repair also.

No leak from the sending unit. The leak was coming from the fuel pump gasket. The fuel pump recently sprung a leak so I pulled it and had it rebuilt and I just got it back in with a new gasket. Hopefully that's it and not the oil pump gasket.

 

[Ward 57]

So grounding turns the light on? I was tinkering and then the light wouldn't come on at all. After some more wiggling of wires it won't go off. l'll trace it back. Thinking the wire is chafed going through the firewall. Bad connection at first and now grounding out. probably have to splice or insulate. Exactly where does it enter? Don't want to tear through the original insulation looking for it.

 

[doug7740]

Current from the ignition switch flows through the Black/Green wire to one side of the oil pressure warning light. On the other side of the warning light current then flows through the White/Red wire to the oil pressure sending unit. If there isn't sufficient oil pressure at the sending unit, the sending unit completes the ground to the engine block and the light illuminates. The wire from the oil pressure sending unit is inside of a small engine harness along with the coolant temperature sending unit wire and the wires going to the ignition coil. The small engine harness enters through the firewall through the grommet on the far left of the firewall.

doug7740
1955 Thunderbird Blue

 

[Ward 57]

Current from the ignition switch flows through the Black/Green wire to one side of the oil pressure warning light. On the other side of the warning light current then flows through the White/Red wire to the oil pressure sending unit. If there isn't sufficient oil pressure at the sending unit, the sending unit completes the ground to the engine block and the light illuminates. The wire from the oil pressure sending unit is inside of a small engine harness along with the coolant temperature sending unit wire and the wires going to the ignition coil. The small engine harness enters through the firewall through the grommet on the far left of the firewall.

doug7740
1955 Thunderbird Blue

Thanks Doug. Now I know where to start looking. I'm suspecting the wire is chaffed and possibly close to breaking buy the way it's acting.

 

[Ward 57]

Thanks Doug. Now I know where to start looking. I'm suspecting the wire is chaffed and possibly close to breaking buy the way it's acting.

I think I found the problem The wiring harness right next to the solenoid looks like it chafed against the firewall and shorted out as the insulation is slightly melted. I'll peel it open and inspect.

 

[doug7740]

After you repair the chafed harness, make sure that you install the harness clip that attaches to the starter solenoid so that it won't happen again.

Clip - Wiring - Not Rubber Coverd - Order 5 Per car-classictbird.com

www.classictbird.com

There is also a clip that attaches the small engine harness to the cylinder head to protect the temperature sending unit wire from damage.

Clip - Temp Wire to Head - Plain - 1 Per car-classictbird.com

www.classictbird.com

doug7740
1955 Thunderbird Blue