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Flushing a defender Radiator

Les Henson

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The following thread is removal of the Radiator and intercooler from a 300TDi CSW in order to clean out the core - internally and externally. Vehicle is owned by DrGoon.

Radiators can be cleaned reasonably well while still in the vehicle, but an after-market intercooler or air conditioning radiator can make this a lot harder, and the most effective way of cleaning the radiator is to remove it. Mud trapped in the fins can greatly reduce the ability of the radiator to do it's job, and can lead to overheating problems. Some types of mud get baked with engine heat and it then becomes very time consuming to remove it all. You can remove the rad/intercooler in one piece, but together they are quite heavy and awkward - especially with the bonnet prop in the way. I chose to remove the two seperately.

Remove top radiator hose and top intercooler hose, then a 32mm water pump spanner on the viscous fan unit. The thread is left-hand, so knock the spanner to the right (clockwise).


Unscrew the fan and carefully lay it inside the fan cowl.

Remove the two 8mm nuts that holds the top of the cowl to the radiator.



The bottom radiator hose splits in three directions - one part goes to the header tank and is held to the fan cowl by two clips.

Close to the steering box


And right at the bottom.


The connection is right at the point where the bottom pipe joins the radiator.


The cowl and fan have to be lifted out at the same time, be careful not to damage the radiator.


Now the amount of mud in the radiator fins can be seen.


The top radiator mounts next, which are retained by 2xm6 nuts/bolts. In order to get at the nuts, you need to remove the grille.

4xsmall self-tapping screws at the top, and 2xlarge self tapping screws at the sides.



The grill panel will now lift away, revealing the air con rad. This is a pressurised unit, so be careful not to damage it.


You can now get at the nuts that secure the radiator mounts to the slam panel 2x10mm.


The two mounts.


The top of the radiator panle now has to be removed - just 4x13mm bolts.



With the top of the frame off, the seperate intercooler/radiator can be seen.


Bottom radiator hose (left) and bottom intercooler hose.


Undo the radiator hose first and it'll lift up and can be laid on top of the engine while still being connected to the header tank.

The interccoler is connected to a metal section of pipe that should be clamped to the inner wing. Undo both jubilee clips (6mm)


The rubber sleeve will then slide up out of the way.


Disconnect the thin bypass hose in opposite corner of the radiator, then undo the two oil cooler pipes (24mm), and tie them out of the way.There are two o-rings for each pipe, make sure you recover them. There will be some oil loss as the oil cooler at the end of the drains down. Find some way of blocking the two pipe stubs.


Carefully lift the radiator and then the intercooler out of the engine bay.



Using a garden hose or pressure washer (held 2-3 feet away), and work slowly across the core of the radiator. It's wise to move the dirt back out the way it came in. Some larger particles will be removed more easily.


Once the dirt is out - clean water will pass through the core quite easily.


Back flush the radiator at the same time. Even though you may have anti-freeze in the engine - there still tends to be a build-up of sludge in the bottom of the rad and elsewhere in the engine.


Keep going until the water runs clear.


A couple of hours later and the core is completely clear - inside and out.


Put it all back together exactly reverse of how it came apart, taking care not to damage the fins of either the radiator or intercooler. Jubilee clips don't need to be mental tight either. if they strip, they have to be cut off, which is very awkward sometimes.

While you have plenty of room, check fan belt, bearings on waterpump, fan idler, tensioner, PAS pump and alternator. A good blast in there with a hose would be good as well.

Les. :)

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no wonder it had problems if the bottom hose had 3 splits in it....

Good thread (as ever) Les, a credit to the forum.

I think what Les meant was the bottom hose diverts into 3 directions -- water pump/header tank/thermostat housing, not splits as in damage.

not surprised Dr Goon has had heating problems with a rad full of crud.he should be ultra toasty now.

Edited by western
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I am amazed at how much crud there was in that radiator and intercooler. I have jet washed it repeatedly to get it clean after the last off-road venture but obviously with the fan shroud in place, there is an awful lot of the rad that the jet wash nozzle just does not get to.

Let's see if there is any difference in heater performance now, especially as Les has left the fan off in readiness for a new viscous unit to be fitted in January.

Once again, excellent thread Les.

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Having given the truck a good run yesterday without an engine driven fan fitted, the temp guage needle never went about about the 1/3 mark, which I regard as normal for the vehicle (when the rad is not coated in muddy goo......... :rolleyes: )

The heater never really did get properly warm and, when I got home, I opened the bonnet and could hold the top hose without any discomfort at all, suggesting that the coolant is not getting particularly hot.

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could be the thermostat thats dodgy & the mud in the rad has been disguising the fault by keeping it warmer? i know on the 200 some had 82degree stats & some had 88degree. i dont know on 300s, but when i had a 82degree stat my heater never got past warm. with the 88degree one now fitted its toasty.

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in that case if you want a better heater id try flushing the heater matrix & checking its not blocked with anything. much the same job, just a different part of the car to take apart. i've seen a few matrixs from regulary offroaded defenders that where totally solid (zero airflow) from being blocked with mud.

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Andy, that's the next job. I have had the truck for 5 years and used it off-road a fair bit. I suspect that there is a lot of dried mud in there, especially when you look at the muck in the radiator.

What had accumulated in there was the result of one off-roading weekend only as the rad and intercooler had been out the previous year and been cleaned :blink:

I suspect that the inside of the heater box resembles a brown brick!! :rolleyes:

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remember to do a thread about it when you do it :rolleyes:

ive had the heater box out of my disco & that was 'fun' with the entire dash out, i suspect a defender shouldnt be as difficult to get too.

something that only occured to me several years after starting this game is so obvious i cant believe i didnt think of it before. put the heater on recycle before playing in mud/water, that should stop most of the crud getting near the matrix - now if only the recycle bit worked on my heater...

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