200tdi overheating (HELP!!!!!)

[JD LWB]

Hi Guys

I've been having a problem with my 200tdi (Defender engine) 110 running hot for a while now.

It never actually overheats, but on a sustained run (20 mins or more), the temp gauge sits just below the edge of the white.

On a run on the motorway, if I travel at 50-60, the temp creeps up, but if I run at 65-70, it sits at or just below the top of the white and doesn't move (I got down to Billing and Malvern along with 2 runs to Shrewsbry and back from here in Derbyshire with no problems).

After a short but fast run (plenty of turbo use), the top of the rad is hot and the bottom (and water in the expansion tank) is almost stone cold.

My first thought was a faulty thermostat (not opening properly and restricting flow).  I took it out and tested it and it works perfectly.  While I was checking the thermostat, I flushed the radiator.  This seemed to be clear (got a bit of gunk out, but not much) and the water flowed freely.

I assume from this that the water is not circuilating properly.  The only causes I can come up with other that the thermostat are, either a dodgy water pump or a blockage in the system (in the Rad or elsewhere).  

Can anyone shed any light on what the problem might be and any solutions.

Thanks

[TULL]

I get this quite often it tends to clear itself, however i always give the radiator a good hours water jetting in the garden you will be amazed what comes out . Just ask anybody who went to Driffield this spring.

[JD LWB]

I know it's not that, the rad is clear externaly (I met you at Driffield, so I know what you mean).

[drmike]

Personally I would replace the thermostat - it's only 4 quid and then you know it's right. I'd also make sure it was a genuine one too as I have heard some pattern parts don't work so well.

Mike

[landyman Ash]

I agree, thermostat to start with
 
I had a rad thast was the problem.  Water ran freely, no gunk but over heated.  Was blocked internally.

Lastly (and well worth considering) as you have a defender have you considered putting a Tims temp guage in?  Its capillary and shows degrees rather thans land rovers black white and red  

The guage is cheap off ebay and screws straight in and being 52mm, it just solts into where your old guage was.  Well worth it I can assure you

[JD LWB]

Ash

I've found the Tim gauges on e-blag, but how do you plumb one in (where and how do you connect 1).

Thanks

[hobbit]

Have a look closely and the fins on the rad, see if the cooling vanes have dissolved, it will flow ok, but not able to cool the system down

run your finger tip over them, mine just disintigrated when I did this on the disco

[JD LWB]

Rad's not that old.  It seems to be in good condition externaly!

[landyman Ash]

Ash

I've found the Tim gauges on e-blag, but how do you plumb one in (where and how do you connect 1).

Thanks

They screw into the old sender position.  I needed an adapter for my Tdi BUT it only cost for 21p from a decent plumber supplier.  The wire cmoes from the guage and goes right into the top pipe bit.  Get some PTF tape too as you dont want a leak  

[JD LWB]

Gauge on order! :D

[JD LWB]

Thanks Ash

Just put the gauge in and it works perfectly.

Didn't need any extra adaptor.

The temp sits at between 88 and 91 degrees now, so it seems like the problem was only the gauge (phew - thought it was going to get expensive). :D

Just need to take it on a good run now to make sure nothing else is wrong.

Thanks again