hi all,
my landrover disco 2 2001 goes to red when I drive. it didn't smoke like overheating it just went all the way up to red. I changed the thermostat and let it run in driveway no issues... as soon as I drove it it went to red again. no clue maybe water pump? help... it seems to be when I drive it goes to red.

 

Air pocket, probably right at the sensor.

1) did you download the RAVE and follow the correct bleed procedure? RAVE is free, link is in sig. line of Savannah Buzz posts (He'll chime in for sure, looks like I'm just up before him.)

2) Get an ultraguage. You are risking slipping a liner on your $7k-to-replace engine. $65 is an easy decision. Find out what your temps really are. Could be a bad sender. Maybe not.

3) Mileage? At 100k, you best swap out the ENTIRE cooling system, including your new T-stat (replace with 180 degree TD5 thermostat or Motor-rad). This includes hoses, clamps, thermostat, water pump, FAN CLUTCH (important), and radiator. If you are still running dex-cool (orange/red coolant), FLUSH the system, and replace with regular stuff.

Should cost you $5-700 in parts, DIY is fine. Again, this is CHEAP insurance because once you slip a liner or blow a head gasket you are essentially done. $2k-ish for a good shop to do headwork, and $7k to stuff in a top-hat long block.

Best to rip out your old rotting cooling system, put a new one in, and monitor constantly with an ultra-gauge.

 

How mechanical are you, have you checked your coolant for oil or oil for coolant?
I would tell you, once you have gone red there can be internal engine issues.
Hve you tested your electric fan and viscus clutch for proper operation.
In the mean time, do not drive it.

 

jesus really... It was just fine and now I have major engine problems??? so no way it is a water pump. does it mtter that it only happens when driving? and mike I cant seem to find ur number and I cant get to the stored email that we discussed my tranny sensor. can u send that to me again. Im so mad, everyone told me to get rid of this truck but I love it. rebuilt the head gasket etc 6mnths ago invested a chunk of change and now I could have major engine issues bc it went to red as if to overheat... insane

 

Air pocket? I m not a mechanic but most mechanics I take it to are ***#@%... they don't seem to know anything abt car and dnt seem to want to work on it. so me and my husband try to do a lot but like I said limited know how. anyone know a good one on longisland in Suffolk county. I didn't bleed the system I just changed thermo and refilled. the antifreeze looks clean and it took about gal and change? was that the wrong thing to do?

 

KP, you might want to send me your number and I'll walk you thru what to check/do.

 

Some facts to consider: Normal temp range with 0EM stat is in the 190s-200s. Electric boost cooling fan shouold come on at 212 (if functioning). That would tell you that Rover thinks 212 is getting warm, time to cool off a little. Red light comes on at 284. To remind you to schedule an engine replacement with dealer. As others have mentioned the oem heat gauge will point at 50% until it gets above 240F. So you are already too hot when it starts to crawl up. The OBDII scanner (Ultra Gauge) will tell you the true temp reading in raw data sent to the ECU.

If you have a big air pocket, it fills with steam. May not have much heat. The temp sensor may not be touching the liquid level and is not giving a good reading. You bleed by elevating the coolant jug (unbolt, bungee cords), open bleeder and keep adding until bleeder flows continous. Don't stop at the first bubble or two. Messy. Do this when truck is cold.

If you hooked up hoses to thermostat wrong bad things happen. The center hose on top goes toward the bleeder T. The side arm hose goes to water pump. Be sure fan belt is correct route, don't want water pump doing the backstroke.

Coul you have a bad sensor? Maybe. Using a scanner you can see the cold engine temp, which should be abot ambinet. Not 150F to start with. Temp should rise in logical fashion. If bad cooling at idle,also check fan and fan clutch. If bad cooling underway, couild be sludged up radiator, you can measure top to bottom on fins and should see less than 10F spread. When sludged up the lower rows are much cooler, and you have 1/2 of a working radiator.