Every once in a while 2003 Land Rover Discovery 2 overheats.

1. Pulled over each time and waited until engine was cool before proceeding home. This has happened 6 or so times in the past year. Now it's happening more frequently.
2. Coolant expansion tank was dry last couple times. Filled then couple weeks later overheats.
3. Checked engine temp with OBD2 scanner and laser temp gun reads 198-210.
4. No diag lights. No codes.
5. Replaced thermostat year ago with grey one. Have idled until 185 and thermostat opens
6. No leaks under the car.
7. Throttle heater bone dry.
8. Once there was a gurgling sound when heater was turned on, but since then no gurgling sound.
9. Often seems overheating is more likely when heater is turned on. But today blasted the heater and no overheating.
10. Auxiliary fan comes on at 200 degrees or so.
11. No oil/coolant. Tranny/coolant mixture
12. There a drop of water coming out the tail pipe every 30 sec or so when engine is warm.
13. Green 50/50 coolant mixture. I started using more water because I was wasting too much $$ on the green stuff
14. fan clutch seems tight enough. Travels less than 5 degrees when I try to spin it. no broken blades. Nothing blocking the rad.
15. Replaced radiator about a year ago.
16. Coolant bleeder screw is dry
17. I ran until warm filled the coolant expansion tank then when shut off engine, green stuff gurgled out. I added more water as the engine cooled down then topped off.
18. No apparent loss of power.
19. idles well all the time. even when cold.
20. No smell of coolant in the passenger cabin
21. Have read forum posts on this issue extensively.
22. 3rd owner. 2nd owner replaced engine I think. Was originally death VIN.

I'm afraid it's a cracked or leaking sleeve. Any ideas? Would greatly appreciate.

 

I just got done fixing a leak where the manifold outlet pipe is, also where the heater core pipe goes into the block. I didn't have drips on the ground because it evaporated before making its way to the ground.

 

I ran the car but do not see any leaking by the manifold outlet pipe. I also looked at the return heater pipe where it connects to the hose going back into the water pump and looks dry.

 

Water drops out of the tailpipe tend to be either a failed head gasket (white smoke out of exhaust on cold engine startup) or else utterly perfect fuel/air mixture ratio.



In contrast, I'd expect the superhot temps of a cracked sleeve liner to evaporate all coolant that made it through the crack.

Hard to imagine a cracked sleeve without the Disco tick from the coolant causing the liner to slip, too.







Buy the $12 exhaust gas test for your coolant to see if head gasket is leaking.

 

Head gasket can leak in more than 2 places, too...

 

Try a new reservoir cap

 

Or try setting your truck on fire and collecting on insurance

 

Thanks to No Doubt I rented one of these tools. OEMTools for head gasket leaks from Autozone. The test showed no head gasket leaks. The ink did not turn blue to yellow.


I drove 10 miles using OBDII scanner checking temperature and it was steady at 189 deg. Sometimes it went to 194 deg at idle. I turned heater on and temp would drop 2 degrees.




Atlantic British says there is a problem with coolant seeping out the sleeves between the aluminum and steel. They seem to have a 'top hat' sleeve solution versus OEM straight sleeve. To identify if you have coolant seeping into the cylinder, you need to remove all the spark plugs when engine is cold. Have someone start up while you see whether coolant shoots out of the spark plug holes.


Anyone try this?

 

I remembered watching this vid on testing what cylinder might be leaking with a head gasket leak. Not a disco but the concept is the same, hope it helps.

 

You can also use a cheap USB boroscope and your phone to look into the spark plug holes... This can be done one at a time after the engine is cool enough to reach in to get the plugs out but still warm enough to still see the coolant bubbling into the cylinder between the block and the head.

When I had a cracked block (water jacket area behind cyl 5) there was not enough coolant bubbling through to spew out if I would have tried the AB method. However it was enough coolant to foul the spark and eventually create misfires. If I cleaned the plug the misfires would go away for a few days and then return.