hi,
I have a W reg Land Rover Discovery TD5 (Auto) and it keeps overheating on long (ish) journeys. It does roughly 50 miles then overheats and pours water out of the pressure cap, I have changed the pressure cap and the thermostat. I guess the water is circulating properly because i have heat inside the car when the car is revving, but when stationary for a while, it starts to blow through cold. I have also fitted a new power steering pump, but do these cars have problems with the Water Pump? the car can run for hours without the pressure cap on outside. Theres no signs of oil in the water and no smoke coming out of the exhaust. Can you help, or give me advice of what to do next?
Thanks.

 

Things that it could be, in no particular order:

1. Coolant level low. Hopefully no coolant being consumed other than overflow.

2. Radiator (and AC condenser) clogged with mud and leaves on outside.

3. Radiator clogged wth sludge on inside, flush (reverse direction), remove al traces of Dexcool coolant (turns to sludge under a wide variety of conditions). Also flush heater core both directions.

4. Won't be fan clutch - does not overheat at idle and slow traffic - but spin anyway when engine hot, and not running. A viscous clutch should not make more than one turn when released and warmed up. When cold should feel like peanut butter inside. No freewheeling allowed.

5. Maybe water pump, but should show up faster than 50 miles.

6. Belt route making pump run backwards.

7. Fan was removed and replaced in reverse direction, now pulls air away from engine, rather than toward engine.

8. Cracked engine or head or head gasket.

 

With the heater going cold at an idle, you have air in the system, which means you have a coolant leak.
I would suggest you do a coolant pressure test along with testing the coolant cap, to find your leak.
Let us know what you find.

 

How long does it take at idle to loose heat?
1 minute?
15 minutes?
Diesels loose heat when idling because the run cooler than petrol engines and that is 100% normal, so is excessive smoke after idling for extended periods.
Check the drive belt tension and condition of the drive belt, if it is slipping it will not turn the water pump fast enough to cool the engine.

 

I have already done a pressure test and bought a new, Genuine Land Rover pressure cap and i still have the problem. When running the engine without the viscus fan on the radiator all the hoses, bar the two bottom ones on the rad, both going to the fuel cooler, which stay cold, could the fuel cooler be blocked?

 

The heater loses heat VERY quickly (1/2 minutes) but from all the comments on this forum and another one I use seem to be pointing to the water pump. So I will change that and see if there is any change.

 

Please report back when fixed.

 

How about i trade you for my 04 Nas DII that does not overheat?

Email me and i will give you delivery address....

 

When you say trade, what sort of deal do you have in mind?

 

It is not your water pump, air in the cooling system causes the heater to go cold, coolant leak or blown head gasket cause the leak, so go back and do the coolant pressure test again, up to 18 pounds for 15 to 20 minutes and get back to us.