Hi all.
I recently have been fixing a HGF (Head Gasket Failure) on my 1986 Series 3 XJ6.
In the midst of this ive been doing some side jobs that are either easier done or any can be down with the head off.
One of these side jobs has been replacing the head studs and core plugs.

Now for the main point of this post.
the studs and core plugs were removed from the exhaust side a few weeks ago and everything looked good all things considered.
however I removed the intake studs and plus the other day and discovered ALOT of "goop/sludge" for lack of a better term.
I assume its due to the coolant and oil mixing and sitting in the block (all I can really think of that would cause it)
I reached out to a friend of mine who has some experience rebuilding motors as this is the first time ive ever gotten this far down into an engine and he suggested I remove the entire block and get it professionally cleaned.
While obviously there isn't an option that will beat that level of cleaning, I dont currently have the budget or time to take on removing the block (at least I think, again im not sure how much more work would go into a block removal but I assume its at least double the amount that it took to get the head off)

So the big question(s) for me here is, is there a way to clean this block out well enough to not be concerned without removing it?

- While I didn't see any sludge any where else (at least to this degree there was some "chocolate milk" in the coolant system but what's in the block is more like chunky mud) should I inspect the heater core and radiator further incase some of this debris has managed to clog itself inside?

-How much more work would go into removing the block from this point? am I something like 3/4ths of the way there and should just pull the trigger or is it more like ive only just scratched the surface in what it would require?

Ill attach a pic below for a better idea of what's in the block.

 

I am assuming the engine is still in the car and the head removed. This makes it difficult to blast out these passages. Your studs look to be in good condition. Put the head back on, remove the water pump and then use a pressure washer in each core plug hole and, if you can through the rear plate opening at the back of the block. Much easier if the engine is out. To clean the block as you friend recommends means a full strip down. You will then be up for many $ thousands. My car is 50 years old now and has never had the mains caps removed. Oil pressure is perfect. Why fix something if it is not broken?

 

I'd say run a pressure washer through those holes,and down the coolant passages to flush out what you can. Is the oil pan still on? If so, you'll need to make sure any water is out of that, and ideally is totally clean.

 

When I rebuilt the engine of my 1980 XJ6, I rebuilt it around an uncracked block, so I started with a bare block on the engine stand. WIth the core plugs out and a hose, plus some wire to poke around inside the water jacket, I got most, if not all of the "gloop" out. I removed all the head studs, and got a tool made up to clear out the tapped holes the studs screw into. However, first I vacuumed out these as well to make sure no gloop had got in. Everything went OK, but it will be a PITA of a job with the engine still in the car. A lot of gloop collects at the back of the block, so really the cover plate at the rear needs to come off, and also the small diameter core plug as well, to make sure it's all removed

I assume you have the slotted block, so won't have to check for block cracking between the bores.

 

Sorry for the late response work and school has been a bit much lately but am getting back around to doing this.
only part im would it be possible for you to send a picture of the cover plate youre talking about?
or is this something thats only accessable with the block out?

for some clarity i have all intake stuff and exhaust stuff removed aswell as radiator, head, ac, and starter. water pump is still attached as well as all the timing stuff.

 

so all in all would you reccomend attempting to pull the block myself at this point or see how clean i can get it while still in the car?

 

My recommendations are for a daily driver.. do not pull the engine for sludge. Change out all studs. Use rust remover on freeze plug holes, put new freeze plugs in with Permatex sealant. Remove thermostat. When all is back together put 1/3 bottle of Downey dish soap in the cooling system with hot tap water. Run engine 5 minutes and let sit over night. Flush out until water runs clear with garden hose attached to radiator cap with garden hose attachment (available at Auto store). Open Block Tap on left side and radiator hose at top. I use large dia. plastic hose over open hose to direct dirty water into 5 gallon bucket.
Close system back up and a can of coolant flush from Auto store. Run engine 10 minutes and let sit over night. Flush again with engine running next day. When water runs clear, remove hose, drain all water from cooling system. Replace any cooling system hoses that are suspect, and install new thermostat. Fill coolant system with 50/50 premixed anti-freeze. All top offs in future should be with 100% anti-freeze. Check for leaks at all hose joints.
You will have removed 95% plus of the cooling system sludge and with proper Cylinder Head installation and torqueing you are good for 75-100,000 miles.
Rgds
David
PS: left out, leave heater on the whole time to clean and not trap any soap or chemical flush in heater core.
Also you must fabricate a 1- 1/2" plug for top of radiator tube where upper hose goes, when you remove hose to put on temporary plastic drain hose.

 

Block off the cylinders/pistons with a heap of rags packed tightly to stop debris.
Get a high pressure water blaster into all of the access holes in the block like core plugs inlet and outlet points and water passengers leading into the head etc.
Use some fencing wire ie 1/8inch (6mm) or similar to work the lower parts of the block and dislodge hard grunge.

After all that I suggest you follow Davids's advice for follow up to achieve the maximum of cleanness.

 

Quick update for anyone interested.

So ive cleaned out all passages best I can with the block still in the car.
I ended up taking a pressure washer to it as the whole engine bay was CAKED in grease and grime and having a lot of the engine removed was a good opportunity to get to places that would otherwise be impossible to clean.
all in all I think it came out quite well!
no more gunk in the block as far as I can tell, my only concerns at this point would be the possibility of some water managing to collect either in the transmission or oil pan, I did leave the oil pan screw off as to allow for any water that may have ended up in there to drain and hopefully that did the trick because removing the oil pan really isn't an option for me at the moment.
as for the transmission I will probably just drop the pan and replace the fluid just to be safe, cant hurt any.

the only other problem I have come across is flash rust in the block from the water drying off, I did dry it best I could (rags, air compressor, a very hot day outside) but there were some spots in which the water dried up leaving rust behind, I dont think this is to concerning considering the state the block was in before, although I figure I should mention it just incase.

lastly the only other concern I really have is possible metal shavings ending up inside of the pistons, this would be due to the studs needing to be removed with vice grips, some of the metal shavings that were made via the vice grips teeth digging into the studs did work their way onto the piston heads, I have blown away or cleaned off any that I spotted but my concern is any shavings wedging themselves between the piston and the cylinder wall, how concerned should I be about this scoring the cylinder walls and causing major issues? all shavings were very very small so my hope is that if anything did manage to work its way in there it would either fall out the other side or get sucked up with exhaust. reguardless I will of course be doing a final deep clean in attempts to ensure no debris are in the cylinder prior to putting it all back together but it was something I wanted to ask about.

 

where is the block tap located on the left side?

this isn't the large fitting that acts as a core plug right? ( as everyone ive asked has said they've never heard of anyone getting that core plug out)
would it be the smaller bolt located near the oil filter?

 

Early engine had it, I think it was deleted towards the end of the 1960's. Should be towards the rear on the left side of the block, just above the ribs. Might be just a plug.

 

Item 10 or 11
Rgds
David

 

The plug rearward of the dipstick tube is the block coolant drain.

 

What I did to hopefully ensure removal of any filings in between the cylinder walls and the top ring of the piston was dip a feeler gauge in grease and work my way around each piston top sliding the greased gauge blade down to the top ring. And do a 360 around each piston a few times, pulling it out a few times. Cleaning it, and redipping in grease again. Repeat, repeat.