Thread: 2.7 TDV6 EGR coolant system delete

Originally Posted by PerthDisco

The EGR coolant circuit is a loop around the passenger seat side of the engine and easily deleted along with the crossover pipe at the back that is in the way of future oil cooler and fuel pump jobs. I think it flows in direction of passenger side.

On the drivers side it amalgamates with the heater core pipe work before the EGRs which is where you need to do some plumbing work to maintain flow but cut off the EGRs here.

The layout of this circuit seems to differ between vehicles or years. According to the flow diagram in the Land Rover workshop manual, what you describe is correct:



But on my MY12 D4 TDV6 it uses t-pieces and there is no connection between the EGR cooler coolant circuit and the heater coolant circuit other than them both connecting into the main engine to radiator circuit. I don't know why they changed it as the plumbing on mine is more complex with some long hoses that go all the way down to t-pieces near the bottom of the radiator in front of the engine.
The models with the fuel burning heater seem to have a similar setup, but they too differ a bit.



The bonus is it made cutting out the EGR cooler coolant circuit even easier though as no creative plumbing required, just the blanking caps.

Originally Posted by twr7cx

The layout of this circuit seems to differ between vehicles or years. According to the flow diagram in the Land Rover workshop manual, what you describe is correct:



But on my MY12 D4 TDV6 it uses t-pieces and there is no connection between the EGR cooler coolant circuit and the heater coolant circuit other than them both connecting into the main engine to radiator circuit. I don't know why they changed it as the plumbing on mine is more complex with some long hoses that go all the way down to t-pieces near the bottom of the radiator in front of the engine.
The models with the fuel burning heater seem to have a similar setup, but they too differ a bit.



The bonus is it made cutting out the EGR cooler coolant circuit even easier though as no creative plumbing required, just the blanking caps.

The EGRs aid in heating the coolant on a cold engine which explains some of the tie back to the thermostat. Probably more useful in colder climes.

Originally Posted by PerthDisco

The EGRs aid in heating the coolant on a cold engine which explains some of the tie back to the thermostat. Probably more useful in colder climes.

What tie back to the Thermostat?

I see a tie in to the heater core, which would result in the heater inside being warmer quicker

Originally Posted by Tombie

What tie back to the Thermostat?

I see a tie in to the heater core, which would result in the heater inside being warmer quicker

Via the big block in the valley I suspect.

Touched on here with note there is a slight difference between models.

DISCO3.CO.UK - View topic - What is the TDV6 running temperature?

Originally Posted by PerthDisco

The EGRs aid in heating the coolant on a cold engine which explains some of the tie back to the thermostat. Probably more useful in colder climes.

Yes, perhaps the EGR aids in warming up the coolant faster but I doubt it. I doubt it because the EGR cooler has it's own mini thermostat (item 3 in diagram below) in it which limits coolant flow through when cold and if the coolant can't flow through when cold then it's not gaining and transferring much heat.


Screen-Shot-2021-09-20-at-11-58-47-am.png

The second reason for my doubt is I doubt the EGR flows through when the engine is cold. If the hot exhaust gases aren't flowing through then you've just got stagnant exhaust case filling the EGR cooler void - I suspect that the thermal transfer is then somewhat limited at this time.
For vehicles that have had the EGR deactivated this is the state all the time as a result of the deactivation - so probably limited/reduced amount of heat transfer occurring for me prior to blanking off.

One of the reasons why it would take longer to heat the coolant up if you bypassed this circuit instead of deleting is you'd be bypassing the main thermostat (or at least you would on the plumbing on mine). This is because the circuits entry and exit are opposite sides of the main thermostat.

All this thread has pushed me to get of my backside and do the FULL delete I had been thinking of doing for quite some time.

I’ve ordered an old EGR cooler for a template so I can make the flange blanking plates to pull the entire system off. I’m then looking to make some heat shields to replace the missing units.

Originally Posted by Tombie

All this thread has pushed me to get of my backside and do the FULL delete I had been thinking of doing for quite some time.

I’ve ordered an old EGR cooler for a template so I can make the flange blanking plates to pull the entire system off. I’m then looking to make some heat shields to replace the missing units.

Bravo. Full documentation and photos please. I reckon their could be some demand for those blanking plates.

Getting access to the buggers will be fun.

I'm not ignoring questions in this thread, I'm simply pushed for time and post when having a coffee break.

*Everyone is in the ballpark with ideas.
*When I said "D4 is more complicated" I ment 3.0lt.
*The 3.0lt, the egr circuit is part of the heater circuit and needs a loop to finish of or rather to complete the circuit, out of the heads (hot coolant) and then into the heater matrix etc.
*A machined blank rather than a rubber end cap, see pic below. Its what I use on the TD5 (and Defender TDCi water pump), same idea but its a bigger blank.

*The early 2.7 had a T piece coming out from the top plastic outlet as some of you noted, the later 2.7 had a single hose, the 3.0lt went back to a T piece.
*The passenger side of the T piece is where I fit one of the machined blanks.
*The other end I had thought went straight to the pipe that feeds the heater matrix.