[8990TRAC]

Hello,
I got a lot of help here last summer, when I rebuilt an old Leyland 262 and I'm very grateful - thanks all those who offered advice 👍

I didn't really use the tractor over the winter, just a bit of moving trailers about, nothing heavy, but I could tell things weren't good, as I was losing coolant, but not onto the floor...long story short, I discovered this:

So...having drained 9.6 litres of milkshake out of the sump, I've started stripping the head down, ready to lift it off and change the head gasket, which I presume (hope) is the problem.

A bit of background; when I tidied up this tractor last summer, I found the radiator bottom hose was split and it had obviously been running with no coolant in it for a while. It runs really nicely, though, so I didn't think the engine had taken any real damage...now I get to find out...

I've not got a service manual, but it all seems fairly straight forward (so far...). I've removed the exhaust manifold, oil breather pipe and the two block to head oil-feed banjos.

The radiator top hose came off the thermostat housing fairly easily.

I've taken the air hose off the inlet manifold, but now I need the advice of wiser, greyer heads...

I'm going to remove the fuel lines from the injectors, but should I remove the injectors themselves?

Once I get the head off, assuming it's not obviously pitted or (God forbid) cracked, should I get it measured and possibly skimmed, or is that overkill?

When I drained the oil, the first quarter litre was neat coolant - does that give any clue as to how it's getting into the sump?

Thanks for any advice and guidance - I really appreciate it!

Thanks,

 

[Fedup]

Advice and guidance. I'm afraid I have very little of either, but plan to follow along here primarily because I've never seen a Leyland engine(or tractor for that matter).

In your opening statement you used the term "rebuilt". I wonder what that means. Was that the engine itself, or the whole tractor overall getting needed repairs, cleaning, and general spruce up?

As for the current engine problem... my experience with diesel engines putting coolant in the oil has been from problems below the head gasket. Holes in cylinder liners, liner O rings or seals, cracks or holes in the block, things of that nature. Cracked heads or leaking head gaskets usually show up in heating problems, using coolant while running, strange colors in the exhaust, rough running, that sort of thing. You usually know there's something wrong before you see water in the oil.

That said, I repeat I know nothing about your engine so I will wait to see what you find when you open it up.

 

[LouNY]

I would pull the injectors and do a compression test, followed by a leak down test.
Both inexpensive and very informative tests to be done before loosening the head.

 

[8990TRAC]

Hi chaps,
Thanks very much for your advice and thoughts.

Perhaps "rebuild" is a bit overly grand I spent last summer welding patches into the cab sides, replaced all the side windows, welded one of the lift arm brackets back together, stripped out all the old wiring and pretty much painted everything. The biggest job turned out to be overhauling the front hubs and steering links. I didn't do anything to the engine except replace all the fuel lines and move the filters to a bracket lower down to make them accessible.

A compression/leak down test sounds very sensible - would bad results suggest piston rings/liners rather than head gasket? I haven't got a compression tester - the engine is a BMC 4/98 3.8 litre diesel, so if anybody knows what thread the injectors are, I'd be grateful to know, so I can buy a suitable gauge.

I'll keep you updated on how it goes...
Thanks

 

[8990TRAC]

Another quick question;

If, as seems quite possible, the source of my coolant leak is in the block, I can get a full rebuild kit for my engine (as above) for only a moderately pain-inducing sum of money.

The kit, though, comes with everything short of a kitchen sink - if I'm planning an in- frame rebuild just to fix this problem, would I be better just getting liners and a head gasket, or is it a mugs game not to replace as much as possible with the engine apart?

I think I already know the answer to that but, again, I'd be grateful for you opinions and guidance.

Thanks

 

[Hacke]

Here is the shop manual AKM4019 (I downloaded it and nothing exploded), it is too large to upload to this forum:

Leyland Tractor Service Manual PDF free download

Leyland Tractor Service Manual PDF 245 262 272 282 462 472 482 free download; History of Leyand Tractors

tractormanualz.com

I do not know much about these tractors, but I know that there were changes made to the 4/98 engine during the years. If the engine has BMC markings, it sounds a bit early for a 70's Leyland. Probably not a problem, but check it. It could be an earlier Nuffield/JCB engine.

Lots of good information:

https://www.thenuffieldandleylandtractorclub.co.uk

The Nuffield Tractor Forum - Index page

nuffieldtractor.com

It is not good manners to redirect someone to another forum, but I think this tractor is not that common in North America. But, please, report back and continue with the communication here.

 

[LouNY]

One other test would be to pressurize your radiator to 15 PSI and leave the oil drain plug out, leave the pressure on for several hours and see if you get water dripping from your oil pan.
Of course that still won't tell you if it's a head gasket or a sleeve o-ring.
Good compression and no excessive leakage on a leak down test would lead a person to suspect liner o rings.

 

[8990TRAC]

Hello all,
Thanks very much for all your help!
I'm fairly certain the engine is a 4/98 - from memory, it's stamped on the block, but I'll double check.
Thanks very much for the link to the manual - I've downloaded it, printed it and will be looking through it for hints tonight.
I'm still looking for pressure fittings that will fit my engine - I think I'm just going to pull the head off and see what it looks like, to be honest. How can I check the liner o-rings once the engine's apart...or should I just assume they're bad and replace the liners, anyway?

Thanks again for all the help!

 

[Hacke]

Hello all,
Thanks very much for all your help!
I'm fairly certain the engine is a 4/98 - from memory, it's stamped on the block, but I'll double check.
Thanks very much for the link to the manual - I've downloaded it, printed it and will be looking through it for hints tonight.
I'm still looking for pressure fittings that will fit my engine - I think I'm just going to pull the head off and see what it looks like, to be honest. How can I check the liner o-rings once the engine's apart...or should I just assume they're bad and replace the liners, anyway?

Thanks again for all the help!

Yes, it should be a 4/98, it was the "BMC" part I thought was odd. Maybe they did not change the molds to show "Leyland" instead of "BMC". I suppose there should be an engine serial number to tell.

 

[8990TRAC]

Hello,

Here's a bit of an update - just one unexpected thing, really so far;

First job was to get the injectors out. Starting at the front of the engine, this one was stuck in good and proper. When I managed to pull it free, it brought the sleeve with it(!) and, as I hadn't drained the coolant yet, the cylinder then filled with coolant...a good start 🙄.

The other injectors came out far more easily, so maybe the first one was the problem? I'm carrying on, taking the head off, anyway...

The next job was clearing away all the coolant and heater pipes. Getting the pipe off the water pump was so difficult, I had to remove the top hose fitting from the head to get at it...

Next, the rocker cover came off without much of a fight - I was expecting much worse than this inside.

Pushrods removed and put through a sheet of card to keep them in order.

The rocker assemble unbolted pretty easily - 13mm bolts (imperial equivalent) at the ends and middle, 14mm half way along.

The last job I did was to remove the head nuts, following the sequence in the manual Hacke kindly uploaded 👍. As I'm working on the engine from a ladder, though, I didn't fancy my chances pulling the head off the block and carrying it, so I need to get an engine hoist in on the act and I've called it a day here.

If the seized injector sleeve was allowing coolant into the front cylinder, could that be the source of my problem here?

Watch this space for the head coming off...
Cheerio

 

[Hacke]

If an injector sleeve is leaking, you would not get water into the sump. Head gasket is still the prime suspect, I think.

A compression test will not be of any use if the injector sleeve(s) is/are leaking.

I have only seen a few engines with broken injector sleeves (no BMC/Leyland) and they were cracked at the bottom edge. Does this have an o-ring?

I suppose you will renew them all anyhow. Stumbled on this one that does not need a special tool for the forming/rolling operation. Maybe you already know of it:

https://www.tractorspareparts.co.uk/images/injectors.pdf

 

[8990TRAC]

Thanks very much for that, Hacke; I've not looked at rebuild parts in any serious way, yet, so that's a great help!

The parts diagram for the head is a bit non-committal regarding an o-ring:

3: Guide-valves
4: Sleeve-injector
7: Washer-sleeve injector
O-ring-injector sleeve

I don't know if that means there is an o-ring, or there used to be but it was superceded (there's no part number)...I'll find out when I get the head off, I suppose...

I'd imagined the sleeve was much heavier than this - what holds it in place at the bottom?

The challenge now is going to be getting the stuck injector out of its sleeve...I suppose I could just cut the sleeve open...

Thanks for your help

 

[Hacke]

Thanks very much for that, Hacke; I've not looked at rebuild parts in any serious way, yet, so that's a great help!

The parts diagram for the head is a bit non-committal regarding an o-ring:
View attachment 78932
3: Guide-valves
4: Sleeve-injector
7: Washer-sleeve injector
O-ring-injector sleeve

I don't know if that means there is an o-ring, or there used to be but it was superceded (there's no part number)...I'll find out when I get the head off, I suppose...

I'd imagined the sleeve was much heavier than this - what holds it in place at the bottom?

The challenge now is going to be getting the stuck injector out of its sleeve...I suppose I could just cut the sleeve open...

Thanks for your help

I know less than you about this engine, but I guess that the groove you see in the attached picture from injectors.pdf is for an o-ring. As I understand it, not all 4/98 had an o-ring.

I do not think anything is holding the sleeve at the bottom.
*** Edit
It looks like I was wrong about that, the picture from the shop manual shows that there is a blind hole with a smaller hole at the bottom for the injector nozzle. Looking at the first picture in your post #10 gives the impression of a straight through hole. Maybe the light area is a water surface above the bottom?
***

 

[8990TRAC]

Thanks for all this 👍
The light surface in that picture is the top of the coolant, which filled that cylinder to the top of the injector hole when the sleeve came out.
The injectors I've got aren't quite like the diagram you've attached, but I guess the sleeve is probably pretty similar.
Thanks for that

 

[8990TRAC]

Well, I borrowed an engine hoist, but a combination of the tractor being too high and the ground being too rough meant there was no safe way of doing it, so I went for plan b...

A back-hoe/loader is like the Swiss army knife of budget agriculture 👍. I hung a chain hoist off the bucket and carefully started lifting...

The head lifted off fairly easily - let's not dwell on the rope lifting sling...

It turns out that this plate, which holds the bodywork in place, is bolted to the back of the head. You can probably imagine my amusement when I realised the bodywork was lifting with the head! When I was finished laughing, I unbolted the bodywork from the plate (the wood panel is OEM, believe it or not, and is also bolted to the plate) and started hoisting again.

Here we are an hour(!) later, then, finally lifting the head clear of the bodywork.

Right, here's the start of the interesting bit; this is the head gasket on top of the block - the gasket was very stuck down in places and had delaminated all over the place, but probably as a result of the head being lifted off.

Here's the block with the outer two cylinders at TDC...

...and with the inner two at TDC. I can't see any obvious cracks, damage, scoring or anything unpleasant at all. The liners aren't loose or obviously damaged. The engine smells like cigarette ash - I've heard it said before that a smell of burnt toast from the oil can indicate head gasket issues, but that might be nonsense...

This is the head face after a quick wipe with paper towels - again, nothing obvious to see here...
So, what should I do next? Would putting a cup of diesel in each cylinder and seeing how quickly it drains tell me anything? There's a lot of carbon and filth everywhere - how much cleaning off should I do?
I'm going to remove the sump and have a look at the crankshaft and big ends, just out of interest, really, so I'll post a picture or two of that when I've done it.
Any suggestions for what I should be looking for here would be very much appreciated!
Thanks

 

[SidecarFlip]

Rusted head studs are usually indicative of a coolant leak. They should not be rusty at all. Your first hole and your second hole, the head gasket shows leakage. In picture 8, the fire ring on the far right looks to be compromised as well. I'd clean all the carbon and filth off before going any farther. Get the old gasket off and use a putty knife and clean the head and the deck. You need to flip the head over and use a straight edge and feeler gauge to determine if it's warped. Same with the deck. There will be a 'flatness' spec in the shop manual for the allowable limit.

 

[8990TRAC]

That's really helpful advice, thanks for that! The cylinder with the leaking fire ring is the one at the front of the engine, which is also the one which lost its injector sleeve, so perhaps that one has taken the brunt of the overheating
I'll do everything you say and take stock - I really appreciate you offering up your knowledge!
Thanks

 

[Hacke]

I am no expert at this, but I see no obvious path for the coolant to get into the sump, or vice versa. I lean more towards the liner seals. I am not sure how to test that. If there are heavy leaks, maybe they can be watched if you fill the block with water and observe the liners when the pan is away. Sealing the system and pressurize it would be best, I think. Better wait for a second opinion on that, though.

 

[SidecarFlip]

Why most modern diesels are now 'Parent Bore'. No crevice seals to deal with.

 

[Fedup]

Just an observer here so my thoughts are worth very little, but I agree with the theory of a bottom end leak as the cause for coolant in the oil. That condition is often easier to identify with the head on and the pan off, but that's not where you are.

I too noticed the area on one cylinder where it appears that combustion has been getting by the fire ring portion of the head gasket. Is that the source of the transfer? Possibly, but I'm in no position to make that call.