2.5 Di Temp Sensors

[TigerDan]

I have a 1992 Di that I've swapped into my 1961 Land Rover '88 (it had formerly been swapped into a SIII 109 before it was imported to the US where I got my hands on the drivetrain after the truck was disassembled and the body used for another project.)

I'm currently rewiring the engine compartment and dash of my Land Rover and have a question about the two temp sensors on the engine. One is located at the front of the cylinder head on the thermostat housing and has a two-wire connector like that used for a Lucas/Bosch petrol injector, the other is located on the right side of the block up fairly high, almost directly under the #3 intake port, right behind the fuel filter which bolts to the intake manifold. It's also a two-wire sensor, it looks appears to go into a water jacket, not an oil galley. Would one of these sensors be used for the temp. gauge and the other to control an electric fan, and if so, which is which? I would assume the one on the thermostat housing is for the gauge, they most gauge sensors I've seen only have one wire.

[dumper]

The one on the side of the block may have been for a cold start setup if it’s a extra one. have you located the oil pressure switch.

[TigerDan]

Yes, that one's pretty obvious, tee'd right into the turbo oil supply line in the oil galley, alongside the oil supply line for the vacuum pump. (This engine had a turbo added to it before it left England 20 years ago.) I can post pics of the two sensors if that would be helpful.

[MinorMatt]

The one on the thermostat housing is for the gauge.

The one on the side of the block is part of a cold start mechanism - the original injection pump would have had a solenoid on the side controlled by that switch to advance the timing when cold. Its not suitable for an electric fan. As far as I can see these were fitted to mk4 engines with bosch pumps and early mk5s (up to early 1996)

These engines were fitted with viscous cooling fans, and have never had provision for an electric fan (aircon models had 2 small addition elec fans, but they were controlled by the aircon system rather than having any switching provision on the engine).

Hope that makes sense?

[TigerDan]

Makes perfect sense, thanks! The cold start mechanism is long gone on mine, but hopefully with the climate here, I won't need it. I am curious about it however and would like to know more about how it works. I do have the Bosch pump, I'll take a closer look at it.

I don't have room for the viscous fan on my Rover installation so it has an electric fan, but I'll use an aftermarket controller as I'd planned to in the first place.

[dumper]

We had a mk3 at work with the cold start system on it and had a glow flame plug in the inlet manifold like the old York engine had.

[MinorMatt]

We had a mk3 at work with the cold start system on it and had a glow flame plug in the inlet manifold like the old York engine had.

Its a different arrangement to that - but yes that was available on 2.5Dis for the -20 degrees C market, this was seperate from the system I describe

[dumper]

The one we had was a export model from a time when sometimes you got what they had in stock it also had twin batteries because of the trouble we had with mk2s twin battery set up with one getting weak and not starting the boss looked under the bonnet and told me to remove the second battery and it’s leads .

[TigerDan]

Would any of these engines have had both cold start systems? I now understand what the extra mounting bracket and lever on the injection pump are for, but I've been wondering about the fitting on the intake manifold, which I finally removed for inspection the other day. It does appear to be a heating element of some sort, but isn't electrically powered.

[dumper]

On the bracket ton the pump I think my 1990 mk3 had a electric solenoid to push or pull the lever to advance the pump timing or it had a wax stat in the water system that pulled a cable to operate it when the engine was cold it pulled the lever then as the engine warmed up it let the lever off.
If it’s starting all right I wouldn’t worry about the manifold electric unit but for the pump timing advance you could fit a pull cable to put it on to start I did do this to one of my vans but really used it as the di is a really good cold starting engine.

[MinorMatt]

Yes thats a flame start in the manifold but the rest of the system is missing

You can see where the solenoid was, and the lever it operated on the injection pump...

[dumper]

Matt was that water operated or electrical or I’m I thinking of the mk1 York that had a solenoid to push the overload button on the minimec pump.so many transits in my life in the past it’s easy to get it wrong cheers.

[MinorMatt]

The flame plug is electrical

The advance solenoid is actuated by an electrical sensor (the 2 spade one by the fuel filter) which measures block temperature (it screws in to the block, but doesn't go in to the water jacket)