Diagnosing overheat on D2

[kcabpilot]

I spent all day today thinking about this. I've owned this truck for almost ten years and in that time I've refilled the cooling system a number of times. Never have I encountered a problem such as this and after trying fan clutch, thermostat, pressure cap and radiator I think it's time to admit that it is indeed either a head gasket or a cracked block.

I did the heads about five years ago at 100,000 miles because of a small leak at the forward end of the left bank. The engine now has 141,000 miles on it and if I'm going to invest the time and money to fix it I'd just as soon do a complete overhaul rather than just head gaskets. It makes sense at this point for new timing gears and chain, cam, lifters, rocker assemblies, oil pump etc anyway so might as well go the whole nine yards.

So that puts me in the position of looking for a new flanged liner block or a way to convert my current block. As I mentioned earlier Atlantic British sells modified short and long blocks but they aren't new and I'd have no idea what their history was plus the shipping to west coast would probably be expensive. I'd probably rather use my original block if I could get it repaired and modified here.

 

[rovercanus]

I bought an engine to rebuild and had the block pinned. Heard some stories about AB motors, I'm not sure I would trust them for the prices they re charging.

 

[kcabpilot]

I've done a lot of reading over the past two days and I've determined that there is one more long shot left before I start taking the motor apart and that is the possibility that one or both of my catalytic converters is clogged. The reason I'm thinking this is because as I was doing my test drive the other day I was monitoring my coolant temperature using a Bluetooth dongle in the OBD2 port and the Torque app on my phone. One of the other displays I happened to have on the screen at the time was my instantaneous fuel mileage and I just happened to notice that it was really pretty bad, like around 11 mpg, never saw more than 13 and that is not normal.

Problem is, how do I determine if there's a flow restriction through my Cats?

 

[Shiftonthefly1]

Temperature of exhaust should be reasonably the same both in and out of the cat. If you have a IR thermometer you can read the incoming and outgoing exhaust temps.

 

[jymmiejamz]

I highly doubt it is the converter as that would be an extremely rare, as far as I know.

 

[kcabpilot]

I agree it's grasping at straws but in one of the articles I read by Robison Service the only two things left on his list are catalytic converters and water pump impeller separation. I can remove the water pump first when I decide to begin removing the heads but I'd like to do some sort of test to see if the Cats are okay. I'd also like to get to the bottom of why my fuel mileage is suddenly so horrendous, the average on last jaunt was 10.8 mpg.

There is also a remote possibility that I screwed up big time. When preparing for the Utah trip I made a mount for the roof rack to hold two jerry cans for extra fuel and to test the auto-siphon hose I had bought I drained them both into the tank. The fuel in them had been there for awhile, quite awhile and I'm not positive about this but it's very possible that one of them may have had 100LL aviation gas in it. The LL stands for (Low Lead) but actually it has a pretty high lead content. I can't be positive about this and it was less than five gallons and also happened a week or two prior to even going on my nearly 3,000 mile journey so hopefully it's not true but I'd sure hate to build a new motor only to see it overheat first time I try to go over a hill. So while the truck is still running I'd like to at least eliminate this far fetched possibility.

I got a cooling system vacuum bleeder yesterday so this weekend I'll drain the system (again) and do a vacuum leak check. If that's good then I'll fill it with distilled water (again) and do some more tests. Perhaps there is something I can monitor from the OBD2 that can tell me more about what's going on with the fuel flow.

From all my research and reading of other people's tales who have been down this road before me it seems most likely to be a cracked block and it can be very difficult to diagnose this without disassembling the engine and doing a block pressure test with the liners removed but before I get there I want to eliminate every other possibility, no matter how remote.

 

[seventyfive]

4 liters usually just blow head gaskets. you said its been up to 260 degrees? it has a blown head gasket for sure now.

 

[squirt]

If you want to test the cats for flow, you can do that in your driveway with a vacuum gauge.

 

[kcabpilot]

4 liters usually just blow head gaskets. you said its been up to 260 degrees? it has a blown head gasket for sure now.

Well if it didn't before there would still be the underlying reason of why it overheated in the first place. From what I've been reading and looking at in my research over the past week most of the blown head gaskets were caused by a cracked block even if they weren't initially diagnosed as such. As I said in the beginning if this engine has to come apart, and it's looking like it will, I am not going to try patch it up with new gaskets. I will do a complete overhaul with top hat liners and yes, I know this is a daunting project that many, if not most, would say is not worth it.

 

[number9]

I read by Robison Service the only two things left on his list are catalytic converters and water pump impeller separation. I can remove the water pump first when I decide to begin removing the heads

Takes about 30 minutes to remove pump to check if you've done before. Why wait?
......

 

[kcabpilot]

I will but for right now the truck is all together. I can move it, he'll I can even drive it into town. Plus I just got the vacuum bleeder so I want to do that check and see what the results are. Basically I just want to go at this systematically and try find the smoking gun, the true culprit. Also, the mention of water pump impeller separations in the article was talking mainly about BMW pumps with plastic impellers, which I don't have so it's a long shot at best. But I will check it first before taking the motor apart.

 

[jymmiejamz]

I've never heard of a Land Rover water pump doing that.

 

[kcabpilot]

Yes a real long shot, I can't even imagine that happening.

So, further research and it comes down to the question of how much is my Disco worth to me? Ignoring the marketplace because there are at least a dozen '00 to '04 Discos locally on Craigslist right now for less than or equal to the number I just came up with to do a proper rebuild of my engine and that number is just a meal at McDonalds short of six grand. This is considering all of my labor to be free lol. So here is a breakdown, I priced most of this stuff off of Atlantic British so I can probably save a bit by shopping around plus with the GBP being so weak right now it's a good time to buy stuff from the UK.

For the block itself I've decided my best option is Q&E in Anaheim. I can exchange or have them do my block with complete top hat liners and new cam bearings for $1500

The rest of the list:

Camshaft 275 (Crower)
Lifters 85 (Crower)
Rocker assys 280 AB
Bearing set 160 AB
Rings 240 AB
Gaskets 250 AB
Oil pump 100 AB
Waterpump 80 AB
Motor mounts 90 A
Hoses 275
Pistons 800 (if needed)
Timing chain 50
Cam gear 30
Crank gear 15
Ign wire set 120
Ign coils 140
Rod bolts 80
Ex valves 160
In valves 180
Valve springs 80
Push rods 120 (if needed)
Valve guides 120
Shop work 500 (I can do everything that doesn't require milling i.e. assemble rockers, install valves, shim etc)
Misc 200 (hardware, fluids, cleaners, lubes etc)

Total comes out to $5975 plus anything I might have missed.

So how much is your Disco worth to you?

 

[Dave03S]

did you ever properly bleed the system with the engine cold?

I just read this whole thread and nowhere did I see that you correctly bled the system.

Maybe you just assumed we would understand you bled the system, but a whole lot of people miss this detail, as evidenced by the many bleeding procedure posts. Sorry if you have but it would help make things clear to know what method you used.

 

[kcabpilot]

I bled the system as I always have successfully in the past, per the manual. Heater worked, no sound of air going through heater core etc. I do have a new vacuum bleeder that I just got the other day and plan to use it this weekend. I should emphasize that I'm still in the diagnosis stage and have not ordered any parts yet. I'm just looking ahead because I've been working on this truck for years and I know my way around it and I'm fairly convinced that there is a major internal issue, one that is often discussed in all LR forums.

 

[JohnB]

Why not get a 4.6 crank and rods if you are going that deep in.


Q&E does appear to know what they are doing and I'd consider using them also since they are West Coast.


That water pump would have been off if this was me if I'd gone through what you have done to this point. If you have a cracked block you would be blowing the shit out of hoses.

 

[kcabpilot]

Yes I've been thinking about 4.6 crank mod. The waterpump is not that old, put it on a couple of years ago and I've never experienced a waterpump failure that didn't include a wobbly shaft and leaking seal. I suppose anything's possible but I'm not suspecting it seriously. Getting it off is easy, getting all the sealant cleaned up to put it back on not so easy and I still want to do some testing and be able to move the truck to where I'll do major work on it if it comes to that.. I do get high pressure in the system when it overheats but that's only when I try to climb a big hill. The rest of the time it acts perfectly normal. Also I've not yet been able to detect any combustion gasses in the system using the block tester so the problem remains a mystery but my bet is still on a cracked block. I've read too many past tales nearly identical to mine while researching over the past two weeks.

 

[jymmiejamz]

Is there any kind of test strips you can dip into the coolant to detect exhaust gases?

 

[kcabpilot]

I have not seen anything like that and I don't think that any combustion gasses actually reside in the coolant because the instructions that come with the block tester explain how to isolate the source by waiting for the gasses to clear then repeating the test with the ignition wires of one bank disconnected and then eventually isolating it down to one cylinder with all other plugs disconnected. This is why you have to have the engine running to do the test and probably why my tests have been negative because it seems that if I do have combustion leaking into the cooling system it is only occurring when I am going up a steep hill. I'd have to somehow put the truck onto some sort of four wheel rolling road to load test it while stationary. Well, that's not gonna happen so I need to think of something else.

 

[number9]

The waterpump is not that old, put it on a couple of years ago and I've never experienced a waterpump failure that didn't include a wobbly shaft and leaking seal. I suppose anything's possible but I'm not suspecting it seriously. Getting it off is easy, getting all the sealant cleaned up to put it back on not so easy

First time change a bitch due to sealant LR used. Shouldn't be a repeat battle cleaning newer sealant/gasket off unless you used one of the popular cement forming sealers some folks insist on doing. I'm confident mine will clean up easily next change after using Hylomar blue on both sides of gasket.
......