Thread: 3.9 EFI D1 motor into my 86 Rangie

Just tiding up a few loose ends and wires now as everything is running as it should. One thing I am having trouble with is working out where to connect my mechanical oil pressure and temp senders into the engine...

There are not the same openings near the oil pump or the thermostat housing as there was in the 3.5, so any ideas where I can stick these?

The oil pressure I could put a tee piece where the oil switch is, but if there is another part of the oil gallery I can stick it in, it would be easier. The temperature is the main one that has me stumped as there is no where I can find to stick that one into. Is the 2 wire sender in the thermostat housing for the factory temp gauge, or does this feed into the ECU? If it is just the factory temp sender, then I could rip that out and stick it in there?

Cheers - Gav

Dunno which oil pump you have but a tee piece in the oil pressure switch hole is what I'd do. Mind out this isn't a pipe thread, you will have to get an adaptor with the correct threads, from a LR shop I suppose.

The 2 wire connector on the thermostat housing is a fan temp switch, it turns on the a/c fan over a certain temp. You shouldn't connect a temp gauge here as the coolant doesn't flow there until the thermostat is open. I would drill and tap a bsp thread behind the thermostat, in the manifold. There should be a single wire sender there somewhere for the stock temp gauge.

Edit: It's low on the front of the drivers side of the inlet manifold, near the head.

Having trouble finding the temp gauge sender... In the manifold on the drivers side is a fitting and hose that runs to the heater, apart from that, I can't find any other senders apart from the AC fan switch mentioned in the thermostat housing.

Geez, finally found it... Hiding behind the ECU temp sender, I couldn't see it from almost any angle.

Ok, so I can't find anywhere suitable to put the existing mechanical gauge - the fitting is just too big, so I have ordered an Electric version and will use the existing gauge sender in the manifold to drive it. Ran my multimeter across it while warming up the engine this morning, and it is a standard 287-23 ohm sender which will drive the 40-120 degree VDO gauge I have ordered, so that one is sorted. Got too hot after that to do anything about the oil pressure, so I'll do that tomorrow after I fit the new temp gauge.

So I fitted a new temp gauge today, and ran it through its paces. All good there, it reads within a couple of degrees from my cheaply IR thermometer. While the engine was warming up, a small puddle appeared under the car from the back of the engine. The floor is still out, so looking for it is easy - or so I thought. Followed the small trail of water up the bell housing of the trannie to a small puddle in the back of the valley. Checked carefully, but couldn't find where it was coming from. Wiped up all the water to see more clearly and ... Nothing. Once the engine was up to temp, there is no leak, nor when it is cold. It is not a one off, as I saw it yesterday while running the engine, but was doing other stuff, so didn't get into it then.

My question is - where could it leak water from that would end up in the back of the valley right where the engine meets the trannie? The heads are too low for anything to end up there, and the heater pipes above it are new and show no signs of damage. The heater core is more to the rear and if that was leaking, it wouldn't end up there.

Anyone got any ideas, as I will need to leave it overnight to cool again, so I can start hunting.

Coolant system seems all fine - engine runs at about 82 to 84 degrees while sitting there, no pressure building in the system, etc. all bled up well - heater working well, etc. No history of issues in the previous vehicle.

Is there a coolant gallery running through the back of the inlet manifold that could be causing this?

Cheers - Gav

The cylinder heads are symmetrical so there are water galleries through the back and the front of the inlet manifold gasket. Try nipping up the inlet manifold, the bolts often self loosen. Otherwise fit a new manifold gasket, not that hard.

Thanks for that. Don't mind doing the manifold gasket, but I didn't want to pull it off for no reason and find nothing there that could leak.

Thanks again - you your prompt and accurate responses are always welcome and appreciated.

Cheers - Gav.

x2 for intake manifold gasket.
When I first fitted the 3.9 to my Rangie it had a leak at the back of the engine. I spent quite a bit of time looking for it with mirrors, etc before deciding to pull the manifold.
I found the two rearmost bolts on the drivers side were only finger tight. I probably could have got away with tightening them, but I had a gasket in the shed so I fitted it.