Coolant Mystery

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meyersd

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I have a '98 Disco LSE. I've had my cooling system issues this summer. Wound up replacing the radiator once and the fan clutch TWICE. Since early August, there have been no cooling issues, except the loss of coolant. After I got my truck back from the second clutch repair (first clutch was defective) I noticed the dreaded anti-freeze smell. No leaks, so I naturally thought it was a head gasket leak. But nothing but exhaust smell is coming out the back. My mechanic told me a while ago I had a small head gasket leak, but nothing major. I only lose coolant on long trips when I have the truck over 70 MPH. At speeds over 70, I notice a slight moaning noise under the hood, although I have not been able to identify where it is coming from. If I travel over 100 miles, I will lose a pint or so of anti freeze. Under normal driving conditions, I lose no coolant. There is never any puddles on the ground. The truck starts and runs like a champ. I'm thinking it may be leaking out and burning up on the cats. Anybody have an idea where my mystery leak might be? Any info would be appreciated.:ahhhhh:
 

joey

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Try the back of the intake manifold, this is where they normally start leaking.
 
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poolorpond

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The fact is that the overheating issues are very well documented in rovers. These engines run rather lean, creating very high combustion cylinder temps. If there are any issues (bad hoses, leaky pump bearings, old viscous clutch, etc) with the cooling system, it will act up. The blocks develop cracks in the aluminum wall behind the sleeves. Coolant usually leaks into the bore (indicated by a steam cleaned bore) and will eventually cause total failure. I would not jump to such a tragic conclusion in your case. But, people throw a lot of money at these engines chasing problems that really began with bad sleeve bores. Be patient. In my case, the lost coolant eventually got worse over time. I did not notice a problem until the heater core started to gurgle, indicating air in the system. Eventually, exhaust gas entered the cooling system and pressurized it. Coolant would get pushed out of the radiator cap. This was the first time that I actually saw any coolant on the floor. I put a combustion leak tester (napa) on the radiator and this confirmed a leak. The problem went from gurgling to bursting over the course of a year. Of course, I only came to this conclusion after replacing head gaskets (twice), rad, visc. cltch, hoses, heater core (failed from increased pressure). . .The failure rate from this prob goes through the roof if the engine is ever allowed to overheat. The coolant has to go somewhere. If you cant find any trail, it might be coming out of the exhaust. They have dye kits that can test this. Spend the money on the tests. It will save money in the long run. The fix for me was a new short block. the heads are usually fine other than a carbon buildup problem on the valves. A quick check by a machine shop is recommended.
 

joey

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Not to sound critical, poolorpond where did you hear that a rover runs lean. I have yet to see a Land Rover that runs lean, they all run very rich... i.e. the main reason they almost always end up with carbon build up on the exhaust ports, and why they are so fond of there fuel. The only way I have heard of a rover running lean is when someone supercharges one and doesnt' install the extra fuel management or bigger fuel pump.
 
M

meyersd

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I took the truck to my mechanic to check it out, and it was indeed leaking from the head. So I bit the bullet and got both gaskets changed and a valve job. Also got the plugs, wires, manifold gasket and valve cover gaskets (they were leaking too) changed. The repair taxed my wallet, but not smelling coolant burning and not having to worry about the old gaskets going critical was worth it. Now I'm back to dealing with the steering box leak.
 
M

meyersd

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poolorpond said:
The fact is that the overheating issues are very well documented in rovers. These engines run rather lean, creating very high combustion cylinder temps. If there are any issues (bad hoses, leaky pump bearings, old viscous clutch, etc) with the cooling system, it will act up. The blocks develop cracks in the aluminum wall behind the sleeves. Coolant usually leaks into the bore (indicated by a steam cleaned bore) and will eventually cause total failure. I would not jump to such a tragic conclusion in your case. But, people throw a lot of money at these engines chasing problems that really began with bad sleeve bores. Be patient. In my case, the lost coolant eventually got worse over time. I did not notice a problem until the heater core started to gurgle, indicating air in the system. Eventually, exhaust gas entered the cooling system and pressurized it. Coolant would get pushed out of the radiator cap. This was the first time that I actually saw any coolant on the floor. I put a combustion leak tester (napa) on the radiator and this confirmed a leak. The problem went from gurgling to bursting over the course of a year. Of course, I only came to this conclusion after replacing head gaskets (twice), rad, visc. cltch, hoses, heater core (failed from increased pressure). . .The failure rate from this prob goes through the roof if the engine is ever allowed to overheat. The coolant has to go somewhere. If you cant find any trail, it might be coming out of the exhaust. They have dye kits that can test this. Spend the money on the tests. It will save money in the long run. The fix for me was a new short block. the heads are usually fine other than a carbon buildup problem on the valves. A quick check by a machine shop is recommended.

I'm halfway thought changing out all the original parts in my truck. This year I'm changed :
plugs
wires
head gasket (with valve Job)
radiator
fan clutch

I did the coil pack at the end of last year. I still need to change:
transmission'
drive shafts
steering box
axels
diffs
belt tensioner

as they will altimately fail.
 

joey

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You must be doing some serious off roading to expect all this to fail. Or you know that the previous owner didn't do any maintenance at all.
 
M

meyersd

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I bought my truck wuth 86K on it. I bought it from a used car lot, but took it to the stealer to get some remotes programmed. The local stealer(where the truck originated) had a service record on it at 50,000 miles. I figured it was probably turned in on lease, or somebody got rid of it before they had to pay for the 90K service. So there was almost 40K of driving that there is no service history. I love the truck, but at times I am puzzed how so many things can go out at once. Most things are minor, which is why I continue to sink the money into it. But I know eventually EVERYTHING will fail, thus the reasoning for replacing everything.
 

joey

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With several Discos on several boards that are still running with over 300,000 miles and just having basic maintenance I am not sure I would agree. Mine has almost 130,000 and no major issue yet.
 
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poolorpond

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joey, it does not sound critical at all. Rover had some issues getting their vehicles to pass govt emissions standards. The result was a different ECU for the us than everywhere else. It runs as clean as possible. The o2 sensor feedback system is designed to keep the air fuel ratio as close to 14.35 to 1, which is a little lean for this engine to run well. ALL reputable aftermarket comp chips enrich the fuel ratio. This does not have to mean poor mileage. The high combustion temp is another indication. Have you noticed when pulling heads that one valve is usually crusty white and the other grey? Yah, the piston tops are usually crusted with dark carbon. But, that could be from leaky seals, round town driving, etc. Additionally, Just because it USES a lot of fuel to move the truck does not mean that it runs rich. Poor mileage could be caused by many things. Even a bad vac advance cold cause 10% decline in economy.

These engines can run for a long time. The initial overheating problem is typically a water pump or hose failure. But if they are allowed to overheat more than a couple of times, they are usually doomed. 25% of 3.9 and 4.2 fail from cracking- 80% of 4.0 and 15% of 4.6.
 

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