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2000 discovery overheating

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Old 02-28-2010, 06:28 PM
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Default 2000 discovery overheating

Ok I bought this thing about 6months ago. I had no issues with it and the previous owner had the headgaskets changed because of overheating long before I purchased it. About the last month it's been overheating without any warning. I swapped the thermostat out in it and had the coolant vaccumed into the system. My buddy works at a foreign autoshot that has everything. Worked 2 weeks without any issues then it happened again. I wasn't getting any flow of coolant into the tubing going to the heater core. I swapped the thermostat again because it seemed like it wasn't opening. I believe the coolant was hot above it and cold below. May have been the opposite. Worked another 2 weeks and then started boiling the coolant out of the overflow so I just topped it off every other day. I only drive this beater back and forth to work because I don't trust it at all and honestly never will. So yesterday i had the heat on and bam it went freezing cold in about 1 second. I get home and it's burping out the overflow. There is obviously coolant in the system because it was comiing ou the overflow tube. Why would the flow suddenly stop when there is plenty of fluid? I let it cool down topped it off with it cold and it worked ok today. I did the exhaust in the coolant check last time I was at my buddies shop and it didn't go full yellow but did change a bit towards greenish. So there is no way a headgasket leak that small would keep pushing out coolant at the rate it is. I can leave it overnight and come outside in the morning and have full tilt pressure in the system lime I just shut it off so that's another thing that makes me think it's not a hg issue. I am basically doing a pressure test all night long and it's still there in the morning. A decent hg issue would drop pressure quickly. I have a car I drag race so I'm pretty decent with leakdown and compression issues. I have been using a brand of thermostat other than lr stat. Is there a chance this is the issue? I've put 2 in it now with no success. I was thinkng of going old school on this thing and popping the guts out of the thermostat just so I could see if this is the issue. Any ideas are greatly appreciated. I always want a disco 2 but my wife decided on a Mercedes ml430 which is also a gian piece of junk. Lol. Thanks guys.
 
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Old 02-28-2010, 06:36 PM
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Hi Flyin2jz
My experience with head gasket. sudden loss of coolant, frequent overheating. Had "sniffer test" ( put LPG in air intake and "smell for hydro carbons in coolant) negative. replaced head gasket now all fine. I gather the best way to tell if head gasket is leaking is to do a short, perhaps moderately hard drive and stop before operating temerature is reached. Check radiator hoses-should still be soft, if firm then prob head gasket. I understand that they usually only need replacing once. Is your head warped? (the engine I mean (;-).

sg
 
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Old 02-28-2010, 06:58 PM
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Thanks for the quick reply. I just don't get the time intervals between the issues. I have always had the water under the dash sound lime there is air I. The system but I drove it 5k lime that without ever having an issue. I know the electric fan is not working but that's not the issue. Although someone less familiar with cars may believe this I simply know better. The electric fan kicks on with extreme driving or when the a/c is on. A good working coolant system won't need this at any time. I'm stumped as to why it holds pressure lime a champ all night. A hg issue would most likely foul plugs or at least run rough for the first few seconds when just started. This thing runs great all the time. I'm half tempted to completely rework the coolant system my way and see what happens. Still only uses a radiator,t stat, fan,waterpump. Why would they make this thing such a trainwreck? I just hate to think of pulling this thing apart as I have never worked on a lr before. I'm sure it's not too bad. I'd be really ticked if I pulled the heads off and mill the heads and it still did it. Which from my research with this issue could very well happen. My guy atthe auto shop I go to said they can use this special stuff that would fix a headcrack or gasket issue bu he says it takes 2 or three applications in the system to fix it. He said the product is cheap but the system needs drained and filled multiple times. Thanks alot.
e
i
 
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Old 02-28-2010, 08:12 PM
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do a hydrocarbon test on the coolant after running the engine, infact you can leave the tester in the bottle as it wrms up and see if bubbles are coming out of the tester if so then your block may have a crack behind a sleeve.
pulling the plugs would also be a good thing to inspect, look for either a rusted electrode or a very clean tip
IE steam cleaned
 
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Old 02-28-2010, 08:57 PM
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I will ask my buddy if he can do that. Can a headgasket be replaced easily. Do u need any special lr specific tools to do the job. I wouldn't be so mad about this issue if it just did it all the time or was a definite issue that could be tested. Maybe the hydrocarbon test cod give me the answer I am looking for.
 
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Old 03-01-2010, 03:14 PM
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Ok I just had it do it again. I felt the top two hoses above the t stat and they are super hot. The hose going to the radiator is cold. To me that seems lime a t stat issue. Seems like it's not opening at all. Lmk what u think.
 
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Old 03-01-2010, 04:51 PM
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Take the thermostat completely out. Check it again.

If it continues to overheat, your radiator might be clogged, I have heard of that happening when oil gets into dexcool.

No, changing the head gaskets is pretty easy. Think of it this way: This is old Buick technology. If you can change the head gaskets on a race car, you can do it to a Rover.
 
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Old 03-01-2010, 05:29 PM
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What would I put in it's place since it's a 3 way stat. I think I may just bust out the insides. They are only 30bux at least these aftermarket ones are. I believe I have some type of gasket leaking allowing air into the coolant system. I also believe air may sit on the stat that makes it close because it is cooler than the coolant and doesn't letthe stat open. I will test my theory by altering the stat. I don't mind a bit adding coolant if it boils out a bit. Just the overheating is really bothering me. Thanks for the info
 
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Old 03-01-2010, 05:39 PM
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https://landroverforums.com/forum/sh...ad.php?t=29258

He has another thread about overheating, 3 t-stats, top rad hose rock hard and hot, lower hose cold, truck overheating.
Turns out it was a cracked block.
 
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Old 03-02-2010, 09:16 AM
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I hate long threads, so I will just say this, DO NOT touch the t/stat, you will cause problems beyond your wildest dreams.
It is obvious you are low on coolant, may not know how to bleed it and need help, so fill it and do a coolant pressure test for 15 minute looking for any leakage. If need be then do a chemical block test to verify blown head gaskets.
In the mean time, do not drive it.
Let us know what you find.
 

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