Where are the glow plugs located?

sideskraft · Dec 25, 2019

I've been unable to locate the glow plugs on my 2540 2.7L 4-cylinder engine. I thought they would be at the top near the injectors but can't find them.

Tractor used to start as soon as the starter engaged, no matter the ambient temp, but in the last 6 months it takes an extra couple seconds of cranking. I'm wondering if one of the glow plugs may be going bad, so I'd like to test their resistance with my multi meter.

If anyone has a photo showing their location on this engine I'd be very appreciative.

Thanks, and I hope everyone had a Merry Christmas!

RNeumann · Dec 26, 2019

Right next to the flux capacitor! JK

Most of the Mahindras use an intake manifold heater. No individual glow plugs. It doesn’t go bad often- it doesn’t see the combustion chamber. A lot of times it’s the fuse or relay.

sideskraft · Dec 26, 2019

RNeumann said:
Right next to the flux capacitor! JK

Most of the Mahindras use an intake manifold heater. No individual glow plugs. It doesn’t go bad often- it doesn’t see the combustion chamber. A lot of times it’s the fuse or relay.

My operator's manual references "glow plugs" on several occasions, but that could be in error I suppose. What I've always thought odd is the key can be turned to the left to heat up the manifold/glow plugs, but it's a momentary switch (won't stay if you let go). The operator's manual states "always turn the ignition key to left for a moment & release it. The automatic heater will start working as will be indicated by a light on the instrument panel. As the lamp goes off, turn the key to the start position to start the engine". The "glow plug heating light" turns on when I turn the key to the left, but as soon as I let go, the switch springs back to the off position and the light goes out. If I keep the key turned left, the light goes out after about 20-25 seconds. The glow plug light turns on and times out when I turn the key to the right one position as well. I don't understand what the reason is for having the left turn glow plug/heater switch, and based on the manual, it sounds like I shouldn't have to hold the key in that position to go through the timer sequence.

TractorNH · Dec 26, 2019

As RNeumann mentioned above it uses an intake manifold heater. It doesn't matter if you turn the key to the left or if you turn it to the right, the heater will activate. I agree it's silly and I never bother turning mine to the left. If I need to preheat it I just turn the key to the on position, wait for it to go out, then crank it. It will also turn back on for a cycle once the engine starts. If it's warm out (above 40 deg F) I just turn the key to on, wait about 5 seconds to allow the computer to fire up and the gauges to normalize and then I crank it.

Anyway, here's a pic from one of the parts lookup websites of the intake manifold for the 2540. You can see part number 16 is the intake heater.

RNeumann · Dec 26, 2019

I’m thinking holding it to the left is only if you need more than the 20-25” the position to the right provides.

RNeumann · Dec 26, 2019

I’m assuming the glow plug intake manifold heater uses its body as the ground. If you pull it for testing be sure to have the body touching a good ground.

sideskraft · Dec 26, 2019

RNeumann said:
I’m thinking holding it to the left is only if you need more than the 20-25” the position to the right provides.

Turning the key to the left and holding it initiates the manifold heater cycle, and it times out the same duration as if you turn the key to the right and wait.

I took my clamp meter, set the current to DC, put the clamp around the cable going to the manifold heater, and turned the key to the left. At first I saw 58 amps and then after about 10 seconds it seemed to flatten out at 53 amps. Is this current draw within spec for the manifold heater?

Deere Dude · Dec 27, 2019

Are you sure the battery isn't almost done?

sideskraft · Dec 27, 2019

Deere Dude said:
Are you sure the battery isn't almost done?

Good question -- often the obvious is overlooked. I keep the battery on maintenance float charge with a Battery Doctor (about 13.2 volts) and it tests out at 750 CCA on both my electronic and old resistor-type load testers.