2002 Disco 2 overheat mystery
#1
03-03-2012, 11:37 AM
2002 Disco 2 overheat mystery
I am new to the forum, first post.
I have a 2002 Disco 2, 107,997 miles.
Last week, noticed temp gauge bottomed out, light on ( i never saw the temp climb, and have not been driving the vehicle much lately) Was in my neighborhood so immediately parked in my driveway, coolant was low, topped it off.
Had it towed to the dealer (as the temp gauge was not reading and i was scared to drive it with no gauge), it was verified that the engine did overheat but no sign of any internal damage. Found a slight leak in the intake manifold and the throttle body heater.
The temp gauge was reset and the vehicle will start up fine (sounds and smells good) then once it warms up if you were to kill it and immediately start it up again it is very sluggish to start or wont start at all. If you wait an hour or so, it will start up fine.
Dealer could not figure out the starting problem and wants to charge an arm and a leg to dig in deep...
Any thoughts?
I have a 2002 Disco 2, 107,997 miles.
Last week, noticed temp gauge bottomed out, light on ( i never saw the temp climb, and have not been driving the vehicle much lately) Was in my neighborhood so immediately parked in my driveway, coolant was low, topped it off.
Had it towed to the dealer (as the temp gauge was not reading and i was scared to drive it with no gauge), it was verified that the engine did overheat but no sign of any internal damage. Found a slight leak in the intake manifold and the throttle body heater.
The temp gauge was reset and the vehicle will start up fine (sounds and smells good) then once it warms up if you were to kill it and immediately start it up again it is very sluggish to start or wont start at all. If you wait an hour or so, it will start up fine.
Dealer could not figure out the starting problem and wants to charge an arm and a leg to dig in deep...
Any thoughts?
#2
03-03-2012, 11:44 AM
important to note, i had the vehicle fully serviced in late October and have put very little miles on it since then. No coolant leaks were found then, and i am confused as to where my coolant went as i have not seen any coolant in the driveway.
No sign of coolant leaking into the cylinders (based off of dealer mechanic's initial review when i had it towed in)
No sign of coolant leaking into the cylinders (based off of dealer mechanic's initial review when i had it towed in)
#4
03-03-2012, 03:03 PM
Super Moderator
As for the gauge:
From the shop manual:
From the shop manual:
Under normal engine operating temperatures the engine coolant temperature gauge
will display in the centre of the gauge. When the engine is cold e.g. from first start-up, the coolant temperature gauge will display in the cold band. When the engine is over heating the temperature gauge will display in the high temperature band. If the engine coolant temperature gauge receives no input or the input is out of range the temperature gauge will read cold and the high coolant temperature warning lamp will be illuminated.
In addition to your coolant problems, this could indicate a bad temp sensor, bad wire connection to it, etc. A code scanner that reads live data can display what that sensor reads, in degrees. If unpluged, it will usually read very low, like -40F. When beginning from a cold start, that coolant sensor and the IAT sensor will be about equal.
And while this is not your whole problem, it should not be the only basis for something like a head gasket job.
As frequently posted, the weekly fluids check is a good ritual to perform.
One of the things that may be mentioned is the possibility of the crank position sensor becoming defective. It normally causes engine to stop, won't re-crank until engine has cooled off. Some users have poured cold water on the sensor to speed up that process. Some have plugged in a spare spark plug and checked for sparks when cranking.
You may have have an internal cooling to combustion chamber leak, which could cause rough running, or starting. Coolant will go out the tail pipe as smoke, may go into the oil (makes it milky). Exhaust gas in coolant test is a $50 one from auto parts store, does maybe 15 tests.
Could just be leaking while driving, and renting/borrowing a coolant pressure tester may find the leaky hose connection, might not leak at idle.
Not trying to second guess Mike, just throwing out some ideas that others will see who may not be on the phone call with Mike. These threads live a long time.
will display in the centre of the gauge. When the engine is cold e.g. from first start-up, the coolant temperature gauge will display in the cold band. When the engine is over heating the temperature gauge will display in the high temperature band. If the engine coolant temperature gauge receives no input or the input is out of range the temperature gauge will read cold and the high coolant temperature warning lamp will be illuminated.
In addition to your coolant problems, this could indicate a bad temp sensor, bad wire connection to it, etc. A code scanner that reads live data can display what that sensor reads, in degrees. If unpluged, it will usually read very low, like -40F. When beginning from a cold start, that coolant sensor and the IAT sensor will be about equal.
And while this is not your whole problem, it should not be the only basis for something like a head gasket job.
As frequently posted, the weekly fluids check is a good ritual to perform.
One of the things that may be mentioned is the possibility of the crank position sensor becoming defective. It normally causes engine to stop, won't re-crank until engine has cooled off. Some users have poured cold water on the sensor to speed up that process. Some have plugged in a spare spark plug and checked for sparks when cranking.
You may have have an internal cooling to combustion chamber leak, which could cause rough running, or starting. Coolant will go out the tail pipe as smoke, may go into the oil (makes it milky). Exhaust gas in coolant test is a $50 one from auto parts store, does maybe 15 tests.
Could just be leaking while driving, and renting/borrowing a coolant pressure tester may find the leaky hose connection, might not leak at idle.
Not trying to second guess Mike, just throwing out some ideas that others will see who may not be on the phone call with Mike. These threads live a long time.
#8
01-02-2015, 01:08 PM
Temp gauge can't be reset.
Temp gauge runs off of a sensor
which goes to the ECU.
The ECU then tells the temp gauge a voltage which makes the temp gauge read what the ECU says it should read.
If you really care about the engine temps, then put in your own
gauge in addition to the not totally worthy built in temp gauge.
Temp gauge runs off of a sensor
which goes to the ECU.
The ECU then tells the temp gauge a voltage which makes the temp gauge read what the ECU says it should read.
If you really care about the engine temps, then put in your own
gauge in addition to the not totally worthy built in temp gauge.
#9
01-02-2015, 08:15 PM
Pro Wrench
If the engine overheats, and sets a code for temp sensor out of range, the gauge stays in the cold position with the light on until the code is cleared. I recently worked on a D2 that had this happen. I cleared it with a scanner and the gauge returned to normal operation immediately. Granted, the gauge would probably have returned to normal operation after a predetermined number of drive cycles, but would you want to drive a D2 with an inoperable temp gauge for any length of time?
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