How to fix question: 1980 CJ7 Renegade 4.2L Oil Leak from rear of pressure gauge

[jdcaples]

I noticed some engine oil dripping from behind the dashboard on to the passenger foot well.

There also a collection of engine oil behind the gauge's glass, at the 6 o'clock position.

Is this a common problem?

Since there's a small, plastic, hollow tube coming off the engine mounted sending unit, I figure it's a classic mechanical gauge with some power for a integrated bulb for illumination.

The engine mounted sending unit was moist with oil, but the tube was dry.

I tightened down the locking nut/collar on the sending unit (10mm wrench) and that's taken care of the engine side weeping.

I spent about an hour searching for a write up or how-to covering removing the gauge from the dash but came up lacking.

Which fasteners do I need to remove to access back of the gauge?

Is this going to be a simple, "make the connection snug" operation, or should I plan to replace the gauge?

I see torx-head fasteners on the outboard sides of the dashboard, close to the A-pillars.

Do I need remove the far bolts on either side of the dash to make some working room, or just crawl under the dash and start removing fasteners in the general vicinity?

I'd rather not guess.

Any hints appreciated. If there's a write up I missed, I'd be grateful for a thread link.

-Jon

 

[mtnwhlr]

What you have is a aftermarket mechanical gauge. I wouldn't waste any time trying to fix it. I bought a Sunpro one from Autozone and it wasn't that much.

 

[Torxhead]

I also think you should consider replacing the gauge with an electrical one. Getting at it can be tricky though. I think your first option to replace it would be by getting underneath the dash if you can. Removing the passenger seat to be able to get at it. This also means changing out the sending unit.

 

[Old Dog]

I'll take another route, if the gauge is working, you can buy a new line for a few bucks.
Sunpro CP7584 Sunpro Retro Line Gauges
As for taking the dash loose (if you can't reach it from underneath) there are also bolts under the dash pad.

 

[jdcaples]

Thank you, mtnwhlr & Torxhead.

So the factory oil pressure gauge was electric?

Is there a reason I shouldn't get an electric kit, plug the engine hole with an electric sender and swap out the gauge at my leisure?

That seems like the fastest way to stop engine oil from escaping its normal circuit.

I don't have a garage and the rain's not supposed to stop for another 10+ days. A couple of weeks will give some rust-dissolving lube some time to work on the passenger seat fasteners.

I expect those bolts be pretty reluctant to come out after 3 decades of wet weather duty.

Thanks again

-Jon

PS: Thank you, too Old Dog (simul-post )

 

[73CJ]

Ditch the mechanical and go electric. It is 2013. . ..

 

[mtnwhlr]

I like the mechanical gauges because you know they are reading right with a electric you are never really sure. IMO

 

[Old Dog]

I like the mechanical gauges because you know they are reading right with a electric you are never really sure. IMO

 

[Torxhead]

JD, a quick fix would be just to plug off the sending unit at the block with a 1/4" pipe plug, fix it when the rain quits. Anyway there are pros and cons between the two types of gauges- accurate pressure readings vs. an oily mess behind the dashboard.

 

[jdcaples]

I grew up with mechanical gauges. This is the first time I've seen one fail at the gauge.

Yeah, I'll block it off with a 1/4" NPT plug, review the reqs for an electric unit and go from there.

Thanks, everyone

-Jon

 

[CJ]

I've never seen a mechanical gauge leak, but anything is possible. If it is defective I would replace it with another mechanical gauge as they are more accurate and you already have the tubing in place.

To remove, usually there are two small metal brackets or one larger one held by two nuts on two studs on the back side of the gauge.

 

[jdcaples]

Thanks, CJ.

I'm not inclined to run a new hot wire if an electric gauge would require it.

I've never seen a mechanical oil pressure gauge leak either, but I suppose there's a first time for bunches of things.

Here's a picture.

View attachment 13750

Yeah, it's a cell phone pic, blurry because, well, it's a cruddy camera masquerading as a phone and I'm better with a digital SLR.

-Jon

 

[CJ]

Sure looks like you need a new one. When you replace it a new hose kit will be included. Cut the old ferrel off and use the new ferrel and the new nut included in the kit. Ferrells should really only be compressed once.