Oil pressure gauge

[dlinmi]

Bought an aftermarket gauge to replace the non working gauge on my MF165 diesel. I wanted to replace the original with one that read by pounds of pressure, not low, medium or high like the original. My question is, the new one came with a small diameter plastic line, that looks to be half the diameter of the original metal tubing line. I believe the size of the connector is the same. Can I just swap out gauges and keep the metal line or will this effect the accuracy of the gauge? I would prefer the metal line over plastic but I wonder if the gauge may be "calibrated " for the diameter of the plastic line provided? Any input as to the accuracy of the gauge if I were to use the larger diameter line? Thanks

 

[Dennis K]

Go ahead and use the metal line.

 

[m16ty]

The diameter of the line feeding the gauge won't matter, it will still read correctly. That being said, keep the metal tubing line if you can mate it to your new gauge, it is much more durable than that cheap plastic line new gauges come with.

 

[Jim.ME]

It may not be as simple as "use the old line". Your MF 165 should have a tee on the back of it that the oil pressure tube hooks to. the second leg of that tee is supposed to have an oil pressure switch mounted to it. That switch controls charging, the fuel gauge and might control other switched electrical items. The original gauge has 1/8" male NPT threads on it to accept the tee. Does your new gauge have 1/8 male NPT threads on it? Many of the aftermarket gauges that use the plastic tube do not, the fitting on those gauges accept the tubing directly. The tee and old oil line will not fit on them. You will need to get creative to maintain the oil pressure switch, if you don't get the correct gauge with 1/8" male NPT thread. They are available with the pound markings as you want, it may take a bit of shopping to find. I have encountered this several times.

 

[Hemmjo]

Your new gauge may have come with bag of adapter fittings. One will be 1/8" male NPT to plastic adapter. Normally you would use that at the engine and run the plastic to the gauge.

If the "T" exists as Jim mentioned, you could put the new 1/8" male NPT to plastic adapter into the existing "T" then run a short plastic line to the new gauge.

 

[Jim.ME]

Your new gauge may have come with bag of adapter fittings. One will be 1/8" male NPT to plastic adapter. Normally you would use that at the engine and run the plastic to the gauge.

If the "T" exists as Jim mentioned, you could put the new 1/8" male NPT to plastic adapter into the existing "T" then run a short plastic line to the new gauge.

If he does that, he should secure the tee and switch, so it is not just flopping around behind the dash. Those risks breaking the line and/or hitting something and causing a short circuit.

 

[dlinmi]

Thanks everyone for your input.

 

[Tim in New York]

Use that metal line if you can! My IH has the tiny plastic line. A few years ago it split while sitting. If I had not needed to go back to the shed for something I would not have noticed the oil path behind the tractor and probably would have ruined the engine.

 

[dlinmi]

Well I ended up buying a copper line kit to make the install. I'm pleasantly surprised with the oil pressure reading if it's accurate. At start up I'm getting 52 pounds and 60 at 1500 rpms. This is with fresh oil, can this be accurate? I bought the tractor used and as long as I have had it the hour meter has been working and currently reads 4595 hours. I wasn't expecting pressure this high. I have blue smoke from exhaust and assumed it was ring blow by, but maybe it's bad injectors. Does this pressure reading make sense? Thanks

 

[Mcrafty1]

Well I ended up buying a copper line kit to make the install. I'm pleasantly surprised with the oil pressure reading if it's accurate. At start up I'm getting 52 pounds and 60 at 1500 rpms. This is with fresh oil, can this be accurate? I bought the tractor used and as long as I have had it the hour meter has been working and currently reads 4595 hours. I wasn't expecting pressure this high. I have blue smoke from exhaust and assumed it was ring blow by, but maybe it's bad injectors. Does this pressure reading make sense? Thanks

Just an FYI my 404 in my 4020 was smoking blue after a rebuild and it was just the pump timing, a slight tweak ( I mean very slight) and it now has all but disappeared, just the usual black puff when you jazz the throttle.

 

[Hemmjo]

Ring blow by would not affect oil pressure. Worn valve guides or worn rings and cylinders would cause blue smoke. Low oil pressures is typically caused by worn bearings, worn oil pump or weakened oil pressure relief spring.