Oil pressure light

[Richard49]

Have a NH TN75 that the oil pressure light stays on. Just changed the oil and filter but it has not changed anything. It flutters and may go out momentarily but comes back on. Bought this tractor used and really like how it performs until this issue came up. Has anyone had this problem? Would appreciate any input.

 

[jaotguy]

only way to check for sure is to pull the pressure sending unit and install a real gauge to get a direct reading ......

could be something as simple as a clogged /defective sensor , right up to a weak oil pump or worn bearings

 

[Soundguy]

deffnately check sender with test lamp from battery, should be on with gator clip to battery and probe to tip of sender, then go out after say.. 6psi comes up.

if lamp stays on, you can put a gauge on if you have one. or slap a new sender in. sender for my 4600 was like 8$, hopefully OP switches havn't gone up too much

post back

 

[RickB]

Also look for a bare or shorted wire leading to the sender. Real oil pressure problems with these Iveco engines are rare. are rare

 

[Soundguy]

good call. if the wire can find ground.. the lamp stays on no matter what the sender does.

 

[RickB]

There's a common pinch spot at the rear of the block.

 

[Richard49]

Thanks for the replies. Will get back with what I find.

 

[Richard49]

Put new OP sensor in and still have flickering light. When I turn on the ignition key and the oil light comes on and then I unplug the sensor shouldn't the oil light go out? If not then are we looking for a short?

 

[RickB]

Put new OP sensor in and still have flickering light. When I turn on the ignition key and the oil light comes on and then I unplug the sensor shouldn't the oil light go out? If not then are we looking for a short?

Yup. Tried to get you to do that before buying a sender.

 

[jaotguy]

time to start tracing the sending wire and look for it rubbing in the body of the unit somewhere ....

 

[Richard49]

Yes sorry I guess I missed that post somehow.

 

[Soundguy]

Yup. Tried to get you to do that before buying a sender.

yes you did..

 

[Richard49]

When you say there is a common pinch spot in the rear end are you saying for electrical wiring or the oil lines themselves?

 

[Soundguy]

wiring. that oil sender is nothing more than a switch. when you turn the key on, it provides power to one side of the oil pressure warning lamp, the other side of the oil pressure warning lamp goes to the sender. with no pressure, the contacts are closed in t he sender, letting the lamp be grounded an on, telling you either no pressure if running, or that the lamp is good at key on.

when running, pressur ecomes up, and the contacts are forced open, thus the lamp goes out.

 

[MikePA]

When you say there is a common pinch spot in the rear end are you saying for electrical wiring or the oil lines themselves?

Are there oil lines external to the engine on a TN75? Just curious.

 

[Soundguy]

i thought that was what we were talking about, a tn75 ?

 

[MikePA]

i thought that was what we were talking about, a tn75 ?

You're right, a TN75.

Richard49 asked if RickB was referring to a place where oil lines or wires could be pinched. I was not aware a TN75 had external oil lines that could be pinched.

 

[Richard49]

Yes I did ask that question. Don't mean to be ignorant but I am asking questions for my husband and some of these questions are mine. He was unable to see any wires at the rear of the block so that is why I asked that question. I really appreciate all the responses. We are going to the farm today and see if he can find the short. Will get back with you.

 

[Soundguy]

Follow the wire from the sender to the harness, then follow the harness, in my 7610s its open and easy, no tn 75 to compair though

 

[RickB]

Are there oil lines external to the engine on a TN75? Just curious.

Turbo supply & return.