Thread: overheating, which way does the water cycle?

blocked radiator.

as a minimum get it hit with a coolant flush treatment, then a flush gun and then again with the coolant flush but you're probably better off getting the radiator rodded.

oh and to answer the question on he edit.. (I promise one day I will think about not posting till the coffee kicks in)

most of the time coolant flow through the radiator is from top to bottom.

300tdi discos and fenders have 3 or 4 core (depends on year) double pass cross flow radiators.

End tanks are are at left and right. Water comes from thermo to top of PS end tank, runs across the top half of the rad to DS end tank then back across to hose at bottom of PS end tank. There is a baffle at the half way point in the PS tank to create the double pass.

With this set up blocking just 1/4 of the cores means you have a 50% blockage. Normally it is the lower cores that fill with gunge. Your radiator needs rodding.

Steve

Thanks fot your help guys, I will report the result of the rodding.

Cheers,
Jarrod.

ok, radiator now rodded(quite an easy job, will post photos in a while) Unfortunately no difference but im starting to think it may be the guage, whilst appearing hot(last white line before the red) I hopped out and slightly undid the cap to relieve some pressure, and quite comfortably ran my hand under the water being pushed out by pressure, it was hot but not as hot as the guage would indicate, infact I could leave my hand under it all day.. but there was alot of pressure pushing that water out, I could hear it bubbling up through the system when pressure was relieved.. also I noticed that when ignition is off the temp reads about 1/4ish or more less than with engine running.. next will be to check over the earths.
Does anyone else know if that sort of pressure is ok under a usually normal running temp?

maximum system pressure is about 14psi. normal operating pressure would be 8-10

you rodded the radiator yourself? and what cap did you remove to get the coolant to flow out from?

not queite same problem, but in my d2 v8 im losing coolant. thought it was from throttle heater so disconected, still losing it. have to top up 2-4 liters every 500km

There is a post on here somewhere about the headgasket and symptoms, worth a check

Originally Posted by lux201

Hi all, I am having an overheating problem with my 96" 300tdi disco, water pump is new and thermostat is new.
when it gets hot the bottom radiator hoses are cool enough to hold but the top hoses are almost too hot to touch.
I am getting pressure buildup in the water system, so first though would be head gaskit but fume tests came back negative and no water in oil or visa versa.
next step is to try to work out if there is a block somewhere, I have bypassed the heater for the moment but this diddnt change anything, I am going to get the radiator rodded next week and tomorrow I am going to check in front of it for debree but for now the disco is barely drivable, it just gets hot too quickly.

Im interested if anyone knows whether the water flows downwards through the radiator, considering the extreme difference in hose temps this would back up my blocked radiator theory.

looks like a kinked hose somewhere or a faulty thermostat try to remove thermostat and see if it heats up got to be your thermostat