DII Cooling System Confusion

kennith

Well-known member
Apr 22, 2004
9,570
14
North Carolina
Too tired right now to think, but I've observed some strangeness. Head and top end gaskets have been replaced, and there is no evidence of coolant or oil contamination.

1: A slow coolant loss, presumably external. I never did find this last leak, but I think I was close to narrowing it down. It was a "top it off once a week if you drive it a lot" affair.

2: Low coolant in reservoir until I open the cap.

3: Pressure or vacuum hiss when cap removed dead cold, even several days later. Haven't checked which yet. It was parked for some time a while back, and I can't remember if that's normal or not. I never had any coolant trouble with this until it blew a hose and a head gasket a while back.

4: Upon cap removal, level in reservoir will rise; sometimes quite a bit, depending upon how much is left in the system.

5: Bleeding procedures seem to function as normal.

6: Heater works.

7: Parked it earlier after a drive at a steady 193-198 on the Scanguage. A few minutes later someone saw it just let go underneath and void the system.

8: It wasn't a good idea to stick my head under there at the time, but that short hose headed to the water pump coming off that plastic manifold appears to have slid back a bit. I'd say it was balooned, but many hose kits just plain look that way. All I could tell was that the coolant was at least coming from that area, as it was still hot at the time and splashing all over the place. It drained too fast to catch it later, so I may just have to pour some in there and see if I can track the leak.

Something in the back of my mind has been telling me this thing is over pressurized. I think I recently replaced the expansion tank cap, but I moved the receipt file during that hurricane and haven't gone out to check yet.

Damned if I can remember which hose blew for certain that popped the head gasket a while back, but it may well be the same one.

There are a few tests I need to do, but now it's obviously not going to be running for a bit, and I've been told I've got several days of rain ahead of me, and perhaps annoyingly cold weather. I'm just too flagged out to remember. Either way it doesn't look like I'm going to be tinkering for a few days, so it's hypothesis time.

Cheers,

Kennith
 

K-rover

Well-known member
Jan 15, 2010
1,878
1
Raleigh, NC
Im chasing something similar. A rarely drive the truck and it seems like every year when the temps fluctuate I get a leaky hose. Usually just have to tighten a hose clamp. I had a small coolant puddle under the passenger side. Traced it back to the hose from the tank to the water pump. That hose is a not standard hose since my coolant tank is on the firewall due to the RTE shock towers. Its been on for 2-3yrs with no issue, but the OD of that hose was way too big. Its all the parts store had with the 7/8's ID. So I tighten up that hose and drive the truck around. I get to where I was going and smell coolant, Check under the truck and its raining down. Well that hose had slid completely off and drained the tank. I put it back on and filled the tank back up then drove it home Everything seemed fine until the next day and sure enough it was leaking again.
So I replaced that hose with a smaller OD hose. Burped the system and did a few heat cycles. Temp stays at 199 at idle and 188 wile driving around. I thought I was good to go, but when I stick hand under the tank it feels slightly wet, but not around the hose and not enough to really leak down onto the ground. Its wet in the middle on the underside. The tank is original from 2001 so Im now thinking the tank has a small crack in it somewhere. if it were the hose, it would be wet around that fitting. Next step is replacing the tank and seeing what happens.
 

kennith

Well-known member
Apr 22, 2004
9,570
14
North Carolina
Annoying, isn't it? :)

This might be a cap, radiator, and thermostat situation, though. It's not that expensive or time consuming to swap them out, and it would eliminate a vast number of variables all at once. I'm not normally someone to just throw parts at something, but I'm not quite in the condition to be bending all over the place just yet. Put most of the meat back on, but I'm still a little iffy.

Best to throw a bit at it and ensure those parts are functional. The thermostat is new, but it's possible that time sitting may have caused a bit of restriction in the radiator. Wouldn't take too much to cause a slow problem that builds over time. Unfortunately, I can't test it now that the system is empty.

Hopefully the leak was bad enough that tomorrow I can pour some water in there and see where it comes out. Hard to tell, as it was under pressure when it popped today. When I removed the cap it started pouring, though, so I think it's bad enough to spot with distilled water. I wasn't about to lay in the muck with hot coolant splashing all over me earlier.

I think my second wind is winding down. Probably going to hit the sack, but maybe we'll get some suggestions.

Cheers,

Kennith
 

JohnB

Well-known member
Oct 18, 2007
2,225
1
Oregon
Sounds like you should use a radiator pressure test kit. Why toss parts that can just confuse the issue.
 

kennith

Well-known member
Apr 22, 2004
9,570
14
North Carolina
Sounds like you should use a radiator pressure test kit. Why toss parts that can just confuse the issue.
Because it's just as much of a waste of time, honestly.

I live in Bumblefuck Stupidville and nothing here ever fits this thing, and also because those parts will only be a few dollars more than one of those kits, anyway. This is one of those places in which residents are infuriated when they are told to go test something for themselves, such as a firearm or telescope, before purchase. We seem to have a lot of stuff here, but we ain't got shit. The closest we've got is an under-stocked Harbor Freight in which no employee or manager knows what they will be receiving in their shipments.

It's not going to screw up diagnosis, anyway.

Every external gasket and seal on the engine has been replaced aside from the rear main. The water pump has also been replaced. The heater plate is currently bypassed for ease of leak diagnosis. All the hoses are new. There's not too much left to go wrong.

That radiator sat for several years, and it's been on the vehicle for nearly twenty years without replacement. I actually bought a messed up unit a while back to send to Griffin to replace the whole damned assembly, but the vehicle needed service first. Now, it's a race for restoration, and I'm not dropping anything nice in there until that engine bay is cleaned up again.

The thermostat is new, but I'm suspicious of pressure here. I can sit back and boil the thing and end up ordering another plastic unit anyway for peace of mind after removal, but again I've done extra work and taken extra time.

The cap is just a cap. No sense not grabbing one, as many times as it's been removed and installed recently.

What I want to know is whether or not the system is meant to remain pressurized or under vacuum that long. Is it the case that it should be that sealed even after several days of sitting? I've never had a reason to even think about accumulating that information. One many vehicles, the answer is no.

I'm also trying to figure out how it could hold pressure like that and still manage to leak externally. It's faster to ask where that could happen than figure it out.

Time is also a factor. I only have half an hour or so every now and again, with no ability to predict when that half hour will be available. I'm not getting enough sleep, I'm exhausted and dehydrated all the time, and to be frank I don't feel like thinking about this issue. Also, I can only drive about fifteen miles right now. My only goal today is to find a few minutes to get out and at least spot where she blew her load yesterday; and I can hardly muster the energy to drive three miles and buy a few gallons of distilled water.

That'll be fun. It happened precisely in the muddiest part of my driveway. Lovely...

Cheers,

Kennith
 

kennith

Well-known member
Apr 22, 2004
9,570
14
North Carolina
Mine stays pressurized for a few days as well.
That much is good to hear.

Just checked. It flat-out blew a hole in the new water pump hose. Didn't pop the clamps, but that's obviously why one shifted a bit. Looks like I got happy with a fucking 1911 down there.

Now the question is why the hell did that happen. I still just have this itch in the back of my mind that the system is over-pressurized somehow.

Could be wrong, but obviously there was a pressure issue in that area.

Cheers,

Kennith
 
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The Fourth Amigo

Well-known member
Apr 20, 2009
641
1
I had similar trouble and it was a faulty cap, cheap one from the parts store. I bought one at the dealer and its been good for over a year.
 
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discostew

Well-known member
Sep 14, 2010
4,499
5
Northern Illinois
Too tired right now to think, but I've observed some strangeness. Head and top end gaskets have been replaced, and there is no evidence of coolant or oil contamination.

1: A slow coolant loss, presumably external. I never did find this last leak, but I think I was close to narrowing it down. It was a "top it off once a week if you drive it a lot" affair.

2: Low coolant in reservoir until I open the cap.

3: Pressure or vacuum hiss when cap removed dead cold, even several days later. Haven't checked which yet. It was parked for some time a while back, and I can't remember if that's normal or not. I never had any coolant trouble with this until it blew a hose and a head gasket a while back.

4: Upon cap removal, level in reservoir will rise; sometimes quite a bit, depending upon how much is left in the system.

5: Bleeding procedures seem to function as normal.

6: Heater works.

7: Parked it earlier after a drive at a steady 193-198 on the Scanguage. A few minutes later someone saw it just let go underneath and void the system.

8: It wasn't a good idea to stick my head under there at the time, but that short hose headed to the water pump coming off that plastic manifold appears to have slid back a bit. I'd say it was balooned, but many hose kits just plain look that way. All I could tell was that the coolant was at least coming from that area, as it was still hot at the time and splashing all over the place. It drained too fast to catch it later, so I may just have to pour some in there and see if I can track the leak.

Something in the back of my mind has been telling me this thing is over pressurized. I think I recently replaced the expansion tank cap, but I moved the receipt file during that hurricane and haven't gone out to check yet.

Damned if I can remember which hose blew for certain that popped the head gasket a while back, but it may well be the same one.

There are a few tests I need to do, but now it's obviously not going to be running for a bit, and I've been told I've got several days of rain ahead of me, and perhaps annoyingly cold weather. I'm just too flagged out to remember. Either way it doesn't look like I'm going to be tinkering for a few days, so it's hypothesis time.

Cheers,

Kennith
Too tired right now to think, but I've observed some strangeness. Head and top end gaskets have been replaced, and there is no evidence of coolant or oil contamination.

1: A slow coolant loss, presumably external. I never did find this last leak, but I think I was close to narrowing it down. It was a "top it off once a week if you drive it a lot" affair.

2: Low coolant in reservoir until I open the cap.

3: Pressure or vacuum hiss when cap removed dead cold, even several days later. Haven't checked which yet. It was parked for some time a while back, and I can't remember if that's normal or not. I never had any coolant trouble with this until it blew a hose and a head gasket a while back.

4: Upon cap removal, level in reservoir will rise; sometimes quite a bit, depending upon how much is left in the system.

5: Bleeding procedures seem to function as normal.

6: Heater works.

7: Parked it earlier after a drive at a steady 193-198 on the Scanguage. A few minutes later someone saw it just let go underneath and void the system.

8: It wasn't a good idea to stick my head under there at the time, but that short hose headed to the water pump coming off that plastic manifold appears to have slid back a bit. I'd say it was balooned, but many hose kits just plain look that way. All I could tell was that the coolant was at least coming from that area, as it was still hot at the time and splashing all over the place. It drained too fast to catch it later, so I may just have to pour some in there and see if I can track the leak.

Something in the back of my mind has been telling me this thing is over pressurized. I think I recently replaced the expansion tank cap, but I moved the receipt file during that hurricane and haven't gone out to check yet.

Damned if I can remember which hose blew for certain that popped the head gasket a while back, but it may well be the same one.

There are a few tests I need to do, but now it's obviously not going to be running for a bit, and I've been told I've got several days of rain ahead of me, and perhaps annoyingly cold weather. I'm just too flagged out to remember. Either way it doesn't look like I'm going to be tinkering for a few days, so it's hypothesis time.

Cheers,

Kennith
 

discostew

Well-known member
Sep 14, 2010
4,499
5
Northern Illinois
Did you deck the heads Kenny? I haven't seen a straight damn head in years. Did you replace the stat? They all suck.

Have you thought about getting rid of it and finding something like a D1 ?
 

kennith

Well-known member
Apr 22, 2004
9,570
14
North Carolina
Did you deck the heads Kenny? I haven't seen a straight damn head in years. Did you replace the stat? They all suck.

Have you thought about getting rid of it and finding something like a D1 ?
I have no reason to suspect the heads. My "proper" heads are currently oiled and in storage. These were prepped and refurbished in whatever manner required. I can see why the mind would immediately go in that direction, but I'm confident enough here that I'll try everything else first.

The thermostat is next up. I'm certainly going to swap it out, given the location of the breach. Shame if a new, quality unit has an issue, but it's absolutely possible, and with enough pressure to blow a hole in a hose, I could have been facing numerous, minuscule leaks not detectable by eye in strange places. If that's the case, it would explain the mysterious coolant loss with no head gasket indicators.

On a D1 replacement:

I have no desire to "replace" the DII. I bought it brand spanking new, and I still have every single receipt and service record. It was sitting back behind the dealership with flat tires covered in dust, as it didn't run quite right. It never has, but it's got more pep than it should. I'm quite attached given all we've been through.

It has been solid as a rock through absolute hell over the years. No issues beyond Amigos and things that have rattled loose. I've destroyed wheel bearings, but that's obvious given my use cases in the past. Hell, I lived in it for a while several times. It's got a "special thanks" credit in a movie, for crying out loud.

That's why I'm hesitant to buy certain SUVs in the same category. Also, I may be short (5'7"), but I'm built like a broad triangle up top, and a D1 just plain isn't wide enough for comfort. I can't even come close to getting in something like a Lotus; and I've fucking tried. Defenders aren't right for me, either. :ROFLMAO:

The problem that ended up causing it to sit started on a test drive after some stuff was done, and it blew an old hose out, drained itself at speed, and there went the head gasket. That was right when the injuries started coming back to bite me, so it just sat there.

I suppose it could have been the same hose, but I'm not entirely sure at this point. If I recall correctly, it was one I'd forgotten to replace, and mud got to it. If it was the same hose, I'm calling coincidence.

It wasn't in my care at the time, as differentials were being set up, and that's not really something I wanted to do. The Quaife units required some adapters and stuff, and I've never had much cause to dick around with that, so it was better to let a drag shop handle it. That was several years ago, so I doubt it was the same event.

So, we're operating under the assumption that a different hose was breached this time, and that the heads and gaskets are perfectly fine.

Cheers,

Kennith
 

discostew

Well-known member
Sep 14, 2010
4,499
5
Northern Illinois
What I was going to say was test for exhaust gasses in the cooling system. You can get a good tester for cheap. Your going to need it if you keep driving that Disco 2.

I personally think its the heads. You bleed it and then you get air in it again. I'm assuming you know how to bleed them. If you take the cap off the reservoir with engine running and you should see that steady stream of coolant down into the coolant. Like a little guy pissing into a pool. If you have that and drive it a little, then check for it again. If your getting air in it again it's coming from a head gasket. Plus. how else would it build up to much pressure? How much air is the fan moving?
 
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kennith

Well-known member
Apr 22, 2004
9,570
14
North Carolina
What I was going to say was test for exhaust gasses in the cooling system. You can get a good tester for cheap. Your going to need it if you keep driving that Disco 2.

I personally think its the heads. You bleed it and then you get air in it again. I'm assuming you know how to bleed them. If you take the cap off the reservoir with engine running and you should see that steady stream of coolant down into the coolant. Like a little guy pissing into a pool. If you have that and drive it a little, then check for it again. If your getting air in it again it's coming from a head gasket. Plus. how else would it build up to much pressure? How much air is the fan moving?
I've got a kit, and it passed the test on multiple occasions. Picked it up a while back when I was sorting leaks. The oil is fine, as well, and I've yet to catch an indication of anything related out of the exhaust. The head gaskets were just done a few months ago.

Yeah, I know how to bleed it. I'm surprised I haven't damaged that old reservoir repeating the process so much. There are some things I don't do because I just don't feel like it, and other things I don't do because I've got some issues at the moment.

What I was trying to figure out was, given the coolant flow direction, why that specific short length of hose between the water pump and thermostat was the one to go, and why it may have happened.

There's not else for me to do right now except swap some of those external parts and test other potential causes. Everything else has been done, and with ten days or so of rain ahead (followed by five days of mud) and an iffy schedule, right by a well-traveled and drained incredibly dusty road, I'm not exactly going to be getting into much detail.

I got that coolant tester when I started to think the pressure was high, expecting the result to be a failed head gasket. No dice there. They aren't perfect, but if it's kicking out this much, one would think even the least sensitive fluid would throw a flag on the system.

Those hoses are tough, after all. The fact that it burst suggests the system didn't vent, but I've got to check the flow diagram again. I was totally zonked out when I checked, but I believe it was between the water pump and the thermostat. I'll have to look again when I get back in a bit.

Finally got two hours of sleep... Ugh.

Cheers,

Kennith
 

discostew

Well-known member
Sep 14, 2010
4,499
5
Northern Illinois
Sleeps over rated. I think your describing a thermostat issue. These thermostats don't work even when they work. They recalled them right after the D2 came out. I put one on any D2 that came near me. There was a green dot on the good ones as I remember, but that green dot was just a sticker I think.

Either that or the hose just let go and your way over thinking this.
 

kennith

Well-known member
Apr 22, 2004
9,570
14
North Carolina
Sleeps over rated. I think your describing a thermostat issue. These thermostats don't work even when they work. They recalled them right after the D2 came out. I put one on any D2 that came near me. There was a green dot on the good ones as I remember, but that green dot was just a sticker I think.

Either that or the hose just let go and your way over thinking this.
I was thinking thermostat, but the breach was the last part of the system, just before the water pump. If it flowed the other direction, it would make more immediate sense, but that's a strange area, and it could still be the cause.

I do know the leaks generally presented themselves when the vehicle was parked. This happened about ten minutes after parking it, and the only reason I know was that I had a visitor who went out to get something from his car, and he saw it happen.

The heater plate simply wouldn't hold a seal. Even a hard copper bypass silver-soldered with barb fittings complained, and that's when I started to get suspicious about pressure. I got another to seal, but it was a pain. The metal water pipe leaving the engine leaked severely, but it was a touch pitted at the sealing bead. Clearing that up stopped that particular leak.

A partial radiator clog before the breach should increase velocity and thus decrease pressure in that location. I should think a stuck thermostat would do the same thing, but that manifold has coolant coming in from two directions, according to the plumbing diagram.

It was still losing a bit of coolant, so I don't think the hose just let go. It's possible, but I still suspect something else. Regardless, I'm going to replace the hose and thermostat and see what happens. I want it working on the factory setup before I modify anything. I've got a question about that, but it's for another thread once this is sorted.

I'm accepting the possibility of a block problem, but I'm ignoring it for now. I want to make absolutely sure everything else has been sorted as well as possible. If it's the block in the end, I'll be replacing the engine and putting mine on a stand for work over time. Probably shouldn't have sold that extra unit I had laying around... Oops.

Cheers,

Kennith
 

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ukoffroad

Well-known member
Jan 13, 2010
1,484
5
Lynchburg, Va
I am in the same boat with this 2000. New head gaskets, radiator, therm, water pump, etc. Drives fine for a week. Randomly it spits coolant out, off the back of the engine. I find it pooled at the front of the engine where the intake bolts are. So far I have checked all hoses, deleted the intake heater, blah blah. Temps run around 195-200 in town, 205-208 sitting at idle.
I guess a new cap is next. bought a pressure tester, sent it back because it would not pressurize. Another one arrived this weekend but have been too busy to even try.

I shit you not, this truck sat for 2 weeks, did not turn it over. In the garage, no leaks. Randomly dumps about half a cup of coolant behind the engine.
 

kennith

Well-known member
Apr 22, 2004
9,570
14
North Carolina
I am in the same boat with this 2000. New head gaskets, radiator, therm, water pump, etc. Drives fine for a week. Randomly it spits coolant out, off the back of the engine. I find it pooled at the front of the engine where the intake bolts are. So far I have checked all hoses, deleted the intake heater, blah blah. Temps run around 195-200 in town, 205-208 sitting at idle.
I guess a new cap is next. bought a pressure tester, sent it back because it would not pressurize. Another one arrived this weekend but have been too busy to even try.

I shit you not, this truck sat for 2 weeks, did not turn it over. In the garage, no leaks. Randomly dumps about half a cup of coolant behind the engine.
It's amazing how these things can make a competent wrench-turner feel like a moron. :)

Cheers,

Kennith