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Discussion Starter · #1 ·
I've read a number of threads on this, but I'm not sure I'm understanding everything correctly. I clearly don't know what I'm doing and I think I've really screwed things up. I'd love some input.

Current situation:
If I try to drive it, it overheats abruptly. When I pull over, steam is coming from the expansion tank. When I open it (I know this is not advised because it can be dangerous, but I used a towel and did it because I was worried the high temp/pressure might be causing damage) it erupts water. This afternoon, I tried to bleed the system by unscrewing the radiator bleed hose and expansion cap, and slowly filling the coolant while the car ran, idling up to 2500rpm occassionally. The radiator bleed nipple had steam coming out of it and drips of water as soon as it got hot, but never let out a constant stream of water, even at higher rpm. It continued to steam and the level in the expansion tank slowly rose and eventually the water in the expansion tank boiled (this is all within about 10 minutes of idling). The truck was parked facing uphill so the front end was elevated. I turned the truck off and came back in.

The history:
The truck overheated the first week I had it, and the coolant was empty, with a leak in the passenger wheel well. A mechanic bypassed the heater and told me it probably needed the heater o-rings replaced.

It drove fine without overheating for 2 weeks.

When I replaced the o-rings (this forum was very helpful for that btw), I didn't do anything special to refill the coolant (I just checked the level and it seemed fine). It drove about 30 minutes before overheating on the golden-gate bridge (quick spike) and I drove it hot for a few minutes before I could pull over without causing a major traffic jam. When I pulled over, it was steaming. I opened the cap and it exploded and boiled over. At that point, I re-bypassed the heater, added water and tested it. It overheated at idle and I sent it to a mechanic (range rover expert in san rafael).

The mechanic pressure-tested the system, and drove it for 30 minutes without it overheating. I thought maybe the pressure testing had cleared an air bubble and it was fixed, and I took it back and drove it happily for a couple weeks before it overheated again (quick spike).

After reading the forums, I tried disconnecting the bleed hose, blowing through it (it sounded like some water came through), reconnecting, then idling while filling the expansion tank, waiting tell the top hose got hot, turning it off and putting the cap back on.

I tried testing it to see if that bled the system and fixed it, it idled fine for 10 minutes, so I drove it to the grocery store. The needle never spiked, but when I got there, the expansion tank cap was steaming. I didn't open it this time. After getting groceries, everything was still a little hot. When I opened the tank to check on it, the water level was down to the neck. I filled it back to cold and drove it for about 3 minutes before it overheated. I opened the cap, it exploded, and boiled over. I added cold water and waited about 10 minutes. Drove it for about 3 more minutes turning the truck off at stop lights (don't know if this is bad or good but I was feeling desperate at this point to get it home). It overheated again, this time exploding so violently that I lost the expansion tank cap in the engine bay and had to go buy a battery for my flashlight before I could find it. The truck made it the final 3 blocks home without overheating again.

Today I did the steps mentioned above in current situation, after unbypassing the heater because I didn't trust the tube that was being used for the bypass (it had some tears in it on the ends from when I got frustrated trying to get it off last time) and I thought that might be letting air into the system.

Questions:

What does steam coming out of the radiator bleed nipple mean? air in the system? immediately too hot? clear sign of one of the problems I don't want it to be? normal and the people who said water should come out didn't think it was worth mentioning what phase the water would be in?

What's the next step? Based on reading threads, I would try removing the radiator top hose and filling from there, but I am not trusting my own decision making abilities in this regard. If I do this, should I drain all of the water currently in it first?
 

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1995-2002 Range Rover P38A
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Just to be clear...

1.) When you say radiator bleed nipple, do you mean the plastic nipple/hose connection attached to the radiator leading to the expansion tank, or the metal fitting inside the expansion tank that should be streaming coolant while the vehicle is running?

2.) How much "water" do you think you've added in emergency, in relation to coolant/water mix as spec'd?

3.) What type of coolant are you using?

4.) Are you positive the hose connection between the radiator and expansion tank is free from all obstructions? Do you have access to compressed air that you could blow through (from radiator hose connection end towards expansion tank) the hose to be sure there's nothing lodged in there?

5.) When filling the expansion tank, are you doing when the truck is cold, and adding coolant/water mix to the cold level graduation on the expansion tank or always when the truck is boiling hot?

Good Luck getting this sorted out - pej
 

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Discussion Starter · #3 ·
Just to be clear...

1.) When you say radiator bleed nipple, do you mean the plastic nipple/hose connection attached to the radiator leading to the expansion tank, or the metal fitting inside the expansion tank that should be streaming coolant while the vehicle is running?
By radiator bleed nipple, I mean the plastic nipple on the end of the radiator that the hose going to the expansion tank attaches on. Today I had the hose removed and steam was coming out of the nipple. Is that maybe normal to come out of the nipple and I should be looking for a stream of water in the expansion tank with the tube connected to make sure there is no air?

2.) How much "water" do you think you've added in emergency, in relation to coolant/water mix as spec'd?

3.) What type of coolant are you using?
At this point, everything that's in there is water. A mechanic told me that was fine for this climate but maybe that's wrong?
4.) Are you positive the hose connection between the radiator and expansion tank is free from all obstructions? Do you have access to compressed air that you could blow through (from radiator hose connection end towards expansion tank) the hose to be sure there's nothing lodged in there?
I'm not positive and I don't have compressed air. When I blew through it, it sounded like some water came out and then the air was going through. When it boiled today, the hose wasn't even connected though.
5.) When filling the expansion tank, are you doing when the truck is cold, and adding coolant/water mix to the cold level graduation on the expansion tank or always when the truck is boiling hot?
Twice now I have added while cold. Once before the grocery trip when it boiled over last. And then again today when I was trying to bleed it.


Thanks for the thorough response and thoughtful questions. I'm in over my head here, so I'm probably not always describing things with the right terms.
 

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1995-2002 Range Rover P38A
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Hi

There must be something wrong in your system. The radiator should be full of water and overflowing through the small line towards the expansion tank. I would look at the thermostat as a start if it malfunctions it does not let water flow towards the radiator but circulates the water over the engine bypassing the radiator.

If the thermostat is working, (You can test it with hot water) there must be something blocked in your radiator that does not let the water flow freely.

Regards

Jos
 

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Also when filling the system, free the expansion tank and lift it so that it's above the inlet manifold when filling. The expansion tank just pops free, if you look at the bottom of the tank it should be pretty obvious.
 

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Regarding water your mechanic really should know better, even a look at RAVE or the Owners manual would give this [extremely basic] info.

There is really nothing to be gained from taking the cap off all the time, indeed you really shouldn't unless you want steam/gas pockets instantly forming (boiling) within the engine block. Fill the system as per RAVE and if that's not working some else is wrong.
 

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Discussion Starter · #7 ·
Hi

There must be something wrong in your system. The radiator should be full of water and overflowing through the small line towards the expansion tank. I would look at the thermostat as a start if it malfunctions it does not let water flow towards the radiator but circulates the water over the engine bypassing the radiator.

If the thermostat is working, (You can test it with hot water) there must be something blocked in your radiator that does not let the water flow freely.

Regards

Jos
Sounds like the steam is a sign that the radiator doesn't have enough water, otherwise water would overflow. I'm wondering if this is something as stupid as refilling with the front end elevated (based on advise to prevent air locks) leaves the expansion tank below the radiator so it's just not filling enough.
 

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Discussion Starter · #8 ·
Also when filling the system, free the expansion tank and lift it so that it's above the inlet manifold when filling. The expansion tank just pops free, if you look at the bottom of the tank it should be pretty obvious.
Thanks for this suggestion. It makes sense that this would be necessary if I fill it with the front elevated like I did. If it's level though, I wonder if this could lead to overfilling?
 

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Discussion Starter · #9 ·
Regarding water your mechanic really should know better, even a look at RAVE or the Owners manual would give this [extremely basic] info.

There is really nothing to be gained from taking the cap off all the time, indeed you really shouldn't unless you want steam/gas pockets instantly forming (boiling) within the engine block. Fill the system as per RAVE and if that's not working some else is wrong.
In the mechanic's defense, I'm sure he knows that the manual suggests a mixture of anti-freeze water, he just didn't think it was necessary in our temperate SF climate. However, I can see that having all water would make the boiling problem worse, since anti-freeze has a higher boiling point than water. As far as leaving the cap off, the RAVE seems to suggest it's okay to leave it off until the top hose gets hot. I wasn't sure if it was useful to leave it off or just a matter of convenience so you can keep filling it. I left it off for longer yesterday mostly because I was confused by the steam and thought maybe it was getting air out of the system and would eventually become a steady stream of water.

My plan today is to put the car on level ground, drain the water, and start over adding coolant exactly per rave instructions.
 

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Not really a defense as its nothing to do with temperate climate, it's to do with corrosion and it does also raise the boiling point, although the cap does most of the job of raising the boiling point.


From RAVE Workshop Manual

" Use an ethylene glycol based anti-freeze (containing
no methanol) with non-phosphate corrosion inhibitors
suitable for use in aluminium engines to ensure the
protection of the cooling system against frost and
corrosion in all seasons. "

"CAUTION: Anti-freeze content must never be allowed to fall below 25% otherwise damage to the
engine is liable to occur. Also, anti-freeze content should not exceed 60% as this will greatly
reduce the cooling effect of the coolant. "

From Owners Manual

" Anti-freeze
Anti-freeze contains important corrosion
inhibitors. Ensure the 50% anti-freeze/water
solution is maintained and topped up all year
round (not just in cold conditions). Failure to
do so may cause corrosion of the radiator and
engine components. "
 

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1995-2002 Range Rover P38A
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The small radiator 'bleed nipple' as you call it may be blocked - doesn't let water through but steams under 'pressure'. If this is blocked then trying to fill the system properly will be almost impossible unless you disconnect the top hose, wait for the system to fill and then reconnect it. To check, if you disconnect the top hose from the 'engine side' and then fill the radiator through the top hose until it is completely full does coolant then run out of the 'bleed nipple'? If not then it may need to be cleaned out - carefully, they are notoriously easy to break off!

Once the bleed nipple is clear but the overheating persists, I would remove the thermostat completely, refill the system and see if it overheats. If this cures things then a new thermostat is the order of the day.

If this doesn't cure the problem does the radiator get hot all over or does it have cold spots. If so, you could try 'back-flushing' the radiator to clear any blockages. Disconnect top hose and bottom hose and run water in through the top hose and let if flush through and out the bottom hose - best done with a hose pipe with some pressure behind it and seal it onto the top hose with rags or similar for the duration. If this doesn't clear any cold spots in the radiator then more drastic action is required. Obtain some central heating 'sludge' remover from your local DIY store, add it to the cooling system, top up and run for as long as you can. Might have to break off occasionally if the engine still overheats. When finished, drain and flush the system through thoroughly with clean cold water.

If that doesn't work and the radiator still has cold spots then time for a new or reconditioned radiator I'm afraid.

If none of the above works or there are no obvious cold spots then I would suspect the water pump.
 
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