Kv6 overheat when drives

[JCLR]

Hi

New on here

Have a freelander 1 with the 2.5 kv6 engine

Had new water pump + Cambelts fitted approx 18months ago

Recently started overheating with top hose being hot + bottom hose stone cold but only when driving, at standstill it won't overheat, I've left it running on the drive for 40 mins with no issues, fans come in then go off and both hoses are hot

Doesn't loose any water, have used a sniff tester on header tank which comes back fine, good water flow, no blockages in rad either

At first I though thermostat so put a new stat in but no change

Any suggestions?

Many thanks

 

[Dorsetfreelander]

Sounds like an airlock, on some engine you have to go through a special sequence of bleeding the pipes.  Might be worth checking but I don't know this engine.

[toastkid]

Any other symptoms?

Doesn't sound like a head gasket - I'd agree with the airlock diagnosis. They can be a bugger to burp.

From Landyzone:

This is the procedure from the LR manual, I figure they spent some time getting it right.

1. Remove bleed screw from heater return hose.
2. Slowly fill the system through the coolant expansion tank until a steady flow of coolant is emitted from the bleed hole.
3. Fit and close bleed screw in heater return hose.
4. Continue to fill system through the expansion tank until coolant reaches to the base of the expansion tank bleed hose.
5. Fit expansion tank filler cap.
6. Start and run engine at idle speed for 5 minutes.
CAUTION: DO NOT operate air conditioning
7. Switch off engine.
8. Squeeze bottom hose several times to remove any trapped air.
9. Start engine and run at speeds varying between idle speed and 3500 rev/min for 7 minutes.
10. Switch off engine and allow to cool.
11. Remove expansion tank filler cap and add coolant until it reaches the 'MAX' mark on the expansion tank.
12. Fit expansion tank filler cap.
13. Start and run engine until normal operating temperature is reached.
CAUTION: The bottom hose must be warm/hot, this will ensure the thermostat is fully open.
14. Ensure warm air is available at vents.
NOTE: If warm air is not available, an air-lock may be present in heater matrix. If necessary, allow engine to cool, remove expansion tank filler cap and repeat bleed operation at heater hose
15. Switch off engine and allow to cool.
16. Check for leaks and top-up coolant to 'MAX' mark on expansion tank
17. Fit underbelly panel.
18. Fit engine acoustic cover.