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Discussion Starter #1 (Edited)
John Deere 4650 tractor. 466 engine is ( suspected) hydraulic-ed. Coolant in a cylinder??? Suspected cracked head/liner, bad gasket or cavitated liner. I'm currently in the process of stripping it down to remove the head to check it out. Anything special to look out for as I go about stripping hardware of it. I'm at the point of removing the intercooler. Presume that after I remove mounting bolts and tubes it can be pulled off of the turbo at the joint. Presume there's an O-ring seal there or something? Not looking forward to removing the exhaust manifold as I'm sure there will be some stubborn bolts that'll break off. Any advice much appreciated.
 

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Turbo has to come off first, do not remove the elbow off the manifold, just the turbo, then intercooler needs to be disassembled, remove all the bolts around where the two halves bolt together, then remove the top part, then the core itself, then you can access the bolts to mount it to the head. Then exhaust manifold is next.
Once you have the head off, be sure not to roll the engine over unless you bolt down the liners, as if you don't, when the engine turns it can cause the pistons to push the liners up and out of the block and bugger up the orings.
When you pull the head, unless you have pulled the injectors, be very careful, they protrude below the surface of the head and you can damage the tips. I usually prefer to pull them. Also watch the injector lines when removing/installing at the pump, you need to hold the pump barrels so they don't turn, takes a 12pt 7/8 flare wrench.
Be best if you could get your mitts on a book, you will need it for the torque patterns and more when it goes back together.
 

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Originally did this as an edit but thought I'd make a separate post so to make sure you didn't miss it...

Was thinking about this and thought I'd add this, if you do some searching on here Lynas you should find a thread from more than a few years ago about head gaskets on these engines, particularly the 46/4850 tractors. Thinking madsnake and madcow were involved besides myself and possibly others, and I think there may be some tech info posted that may help you some, but still you are going to need the book and some tooling. In the later years, there were about three different styles of head bolts and such, and each required different methods and more. Not sure if they still provide the booklet with the updates in the gasket kits anymore. The tooling comes into play as there is no timing marks, engine is timed with a pin in the flywheel and you need a turning tool to roll it over. This is needed to reset the valve train.
Needless to say, don't get into this unless you really need too lol
 

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Discussion Starter #5 (Edited)
What's the back story on it?
What makes you think its locked??
Backstory is that it's been pushing coolant out the radiator overflow, even on start-up when cold. Sometimes I would use it and it wouldn't put much out at all. Other times it would use lots. Suspected it was ingesting the coolant elsewhere as well but couldn't figure it out. No water in oil. It was running hot so I removed radiator and had it professionally serviced. After that it didn't overhead much but still poked out coolant I had the coolant tested for combustion gasses and test was inconclusive. I already had a new waterpump on it, plus thermostats plus radiator cap. I reinspected these and they're all good. Finally narrowed it down to cracked head/Liner, gasket, cavitation/electrolysis or O-rings although O-rings wouldn't explain the pressurisation at the radiator. Tractor would start okay but sometimes would sound slightly rough on start-up (like a miss). Went to start it one day and she wouldn't turn over...just a clunk as the starter tried to kick it. I've had coolant in a cylinder a couple times before on tractors, so know the feel of a hydraulic-ed cylinder. I'd been told that if it is a suspected head gasket, the engine will run really hot since combustion gasses are mega hot, but it wasn't running that hot after the radiator was serviced, so that confused me somewhat.
So I've been waiting for a sign that would narrow down the problem and I guess a hydraulic-ed cylinder is telling me something.

I'll probably get a pro to pull the head/injectors once I've removed the hardware off it. Don't want to stuff anything up! :)

Engine has 8500 hours now. It was rebuilt at around 4-4500 hours. 2nd owner purchased it then and a few years later he had overheating issues and ended up getting the radiator serviced. Head was removed, checked, machined and reassembled. I bought it sometime after that and have run it for a few years just fine.
 

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That sounds like a head gasket issue Lynas, surprising you haven't been getting some water in your oil as well unless you haven't checked the plug for it.
Usually its the 48s that gave trouble as they were pushing the limits of the 466 in them and then especially if the pump got turned up that just made it worse.
I've lost count of how many times the head has been off mine since new, (I know the history on mine and its over 13K), and it is always between 4&5 it lets go, begins simply losing small amounts of water and then progressing to where she simply blows most of it out. If it has been going on for a while, you may need to get your head planed, as cavitation happens when the fire ring blows and water is present. Becareful getting a reman head, they may not want to give you credit for your old one, if so repair it.
I have heard of head bolts breaking on some of them as well, anything like that can cause the gasket to go south. Heat is an issue as well, finally pinpointed on my 48 it was the air seeder that was taking it out every second year thereabouts, between the high load and heat that did it. Retired the pto powered air seeder, haven't had to go there for a while now knock on wood lol. There again, it don't do much heavy lifting other than the one combine anymore now, hell been feeding silage with it all winter, does more chores that anything.
Any question just ask. BTW, in the 50 series, engine serial number comes into play with parts and more. Was changes during production.
 

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Besides getting head checked/planed id check liner protrusion and make sure the block is straight. Heads always seem to get checked but never those two things. And dont reuse the old head bolts... pretty sure the head bolts were updated but its been a very long time since i worked on one of those.
 

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Besides getting head checked/planed id check liner protrusion and make sure the block is straight. Heads always seem to get checked but never those two things. And dont reuse the old head bolts... pretty sure the head bolts were updated but its been a very long time since i worked on one of those.
THIS^^^^
Absolutely critical.
Always new bolts on JD.
 

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Before you get too horny about ripping it all apart, pull out the injectors first to make sure it's hydrolocked like you think. And if it is, is it coolant or fuel? And also will tell you which cylinder is the issue, sometimes by the time you get a head pulled off you will have coolant running into some of the cylinders and that just makes it a little harder to find where and why it did what it did.
 

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If the charge air cooler was leaking pretty bad it would fill up the intake until it started running into an open valve so yeah that could hydro lock it but probably the least likely. It would be really apparent when you take the intake apart if it was leaking or not.
 

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Leaking intercooler into the intake could cause the hydrolock.
But it doesn't really fit with Lynas back story.
Backstory is that it's been pushing coolant out the radiator overflow, even on start-up when cold.
That indicates a compression leak into the cooling system.
 

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Discussion Starter #16
I'm gonna have a guy pull the injectors and run a pressure test first.
 

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Just gotta check the easy simple stuff first.. always.
Reason being I remember an instance where somehow starter drive tooth hit a ring gear tooth just right and jammed up. Turned it backwards a couple degrees and good to go... so like mentioned, popping injectors is probably a good idea and give you good insight into identifying the root cause.
Good luck.
 

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I'm gonna have a guy pull the injectors and run a pressure test first.
Most likely a head gasket or a cracked head if you are blowing water out. Leaking intercooler is unlikely.
Problems with the head gasket can be caused by liners not protruding above the block (should be about 2 to 4 thou above the block) and I have had to shim liners on occasions.
A friend who is highly experienced with overhauling diesel engines, tells me you must always replace the head bolts on John Deere engines or you will likely break a head bolt in the future and cause problems. These are not cheap from JD parts but are available from after market suppliers at a much reduced price. On an 8.1 litre JD engine, the head bolts are very tight with an exact sequence to tighten them. Initial tension is 55 ft/lbs and then another 3 tightens in sequence of 90 degrees each time for a total of 270 degrees. The last 90 degrees requires a strong arm and/or a long lever. Apparently this is an updated method and almost feels too tight for my liking and is probably why the bolts break if they are reused.
As has been suggested, it is advisable to remove the injectors before removing the head to prevent damage.
Hope it works out well for you.
 

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The head bolts are referred to as torque to yield bolts.
They are single use only.
And for as much trouble as JD has with their engines and head/gaskets in particular the 4wds new bolts are just a normal cost of doing the job.
I thought kevlars idea was good to remove the injectors first.
Probably they need overhauling by now anyway and secondly to narrow down whats in the cylinder and which one is affected.
Plus head removal will be easier with them removed.
Sometimes head gasket failure isn't always that apparent by looking at the gasket.
 

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Took me a bit but I found that thread for you Lynas, knew Madsnake was involved but what threw me was it was for a 8440 instead, but thats basically the same engine as yours. Everything about the change in head bolts and more is there and be some good info you as I suggested. I just get tired of typing the same info out time and time again each time someone asks, guess the older I get I suppose I lose interest in taking the time lol.

 
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