Does this sound like a blown head gasket or cracked engine block to you guys?

2003 Land Rover Disco 2, 140K

Overheated this weekend. Was in red zone. I don't know for sure how long. We took a 10 min drive when we got there the temp light was red. The engine was running fine. No rough idle. No loss of power. No funny noises or smells. We turned off the engine immediately. There was some steam coming out of the expansion tank cap. There was a small puddle underneath the overflow hose. We had lunch. After, I topped off the expansion tank. Drove down the street 1 mile then it started to over heat again. We pulled off and towed home.

I boiled the grey thermostat. It opened at 185-190 F. The grey stat is about 1 year old. Radiator is about 1 year old. All new cooling hoses about a year old.

I put thermo stat back in. Idled and noticed temp started rising 205...210. I turned engine off. I think there's more air in the system. I ran the heater. Engine was running fine. No skips. No rough Idle. No funny noises No funny smells. No heater gurgling sounds.

The throttle heater is bypassed. Was not leaking coolant beforehand. Was not overheating after throttle heater bypass. No white plume of smoke upon cold startup. I used green coolant but now just water after overheating because the green 50/50 is just too expensive until I figure out what's wrong. I checked the dipstick and do not see water.

Nu puddles underneath.

OBD-II says P1663: P1663 - Throttle angle / Torque signal (power stage) Drive cycle A:Signal missing. Not sure could be unrelated to overheating.

No other codes. Next step, Autozone blocker tester.

Does this sound like a blown head gasket or cracked engine block to you guys?

 

Could just be a leak given the puddle. Would be good to run it and identify where the leak is coming from. Does the small return tube from the radiator to the overflow bottle cycle coolant when the engine is cold (and running)? If not this could indicate a failed water pump. How much coolant have you had to add? Pull the plugs and look for steam clean.

 

 

7 & 8 are most likely suspects in a head gasket failure... internals, 3,4,5 & 6 are most likely in a cracked block scenario...

However the above posters are right, you haven't yet ruled out the other most obvious causes, water pump and front cover gasket failures.

Do the pressure test, find the leak, go from there.

 

Put a hose repair bushing in the spot where the thermostat goes on the lower hoses, put the top radiator hose on the metal intake manifold coolant pipe. Essentially bypassing the thermostat. You can run it in the driveway with the top radiator hose disconnected from the radiator with a house water hose stuck in the radiator. If it idles forever without getting over about 130-140, put the radiator hose back on and fill it with water and let it run - should stabilize about 160-170. Leave the cap off while you are doing this and see if you have bubbles in the tank. If it checks out in the driveway, drive it around like this. If it overheats driving but does not in the driveway, you have a plugged radiator (unlikely based on your description).

I believe you have a bad thermostat - the Disco has weird thermostat and I have had several issues.

 

I would replace thermostat. Even if your water pump is leaking coolant if the coolant flow is continuous it wont overheat unless coolant was really low to start with.

 

There was no leak. It was overflow puddle because the coolant boiled over in the expansion tank and out the overflow tube.

I rented a block tester from Autozone. Fluid did not turn yellow.

I ran the car in the driveway this morning. OBD-II showed temperature climbing and climbing.200..204...208..210...215. so I turned the engine off.

I did boil the thermostat (grey) last week and it opened at 185.

Blocked radiator? It was put in last year.

Water pump was replaced a few years ago too.

Again no leaks. Engine idles smooth. No codes except P1668 pending. P1668 = Anti-Theft Alarm serial link faultDrive cycle A:Signal out of range - above maximum

 

Bleed the air out of the system first before you start it again. Simply unclip the expansion tank and hold it up about a foot or more above the engine bay. Top off and repeat until you stop hearing any gurgling. Have you checked your passenger floor board? If a heater core leaks thats where you'll notice it.

My guess is a thermostat. I ran the grey one for a while but ultimately switched to the motorad set up. One of the best mods you can do for this engine.

 

I removed the top coolant hose where it goes into the top of the radiator and ran a garden hose directly into the radiator. The other end that ran from the engine and thermostat over the top of the fan shroud was open. I ran the engine and temperature stayed at 208. Coolant was not gushing out of the open top hose however. Is that normal?

I did bleed the system as suggested by raising the expansion tank about 1 ft and topped off until all gurgling stopped. I did not have a hose relief bushing that Extinct suggested.