Coolant plug TD5 cylinder head thread......assistance reqd

[Nomad9]

Hi There,
So I embarked upon the quest to repair a coolant leak on the plug on the stepsons TD5 cylinder head. The job went from good to a nightmare in about five minutes. Thought my problem would have been the manifold studs, nah!!!! They were easy in comparison to the next task....... The coolant plug undid quite easily for about a turn and a half then is steadily got tighter and tighter until the allen key turned in the plug.... :eek:

Then is was out with the drill and four hours of using every tool in the tool box to get what was left of the plug out without damaging the cylinder head. Fat chance.........:censored:

The plug is now out (all the parts even the one that dropped into the head) and the thread looks average, before I rip the head off I want to try to fix another plug back in, this is now where I am at. Does anyone know what thread is in the head? Is it 3/4 BSP? Don't think it is NPT however if someone knows that would be appreciated.

I thought that taking the plug out whilst the engine was warm would have been a benefit however I'm now not so sure, any learnings here would be good. The threads galled up, that was the problem.

Cheers Marty.

[BMKal]

Marty - if it's the same plug I'm thinking of, you might struggle to find a genuine LR replacement. My young bloke had this plug fail on my old D2 a little while back.

Subaru uses an almost identical plug in one of their engines. Give Steve at Lifestyle 4WD in Morley a ring (9271 7500). He sourced the correct plug and fitted it, and will know what thread it is and where to get a replacement.

I think that they may have had to modify the Subaru plug slightly - Steve will be able to confirm this ..............

If he needs a reminder, tell him it was Shaun's grey D2 from Kalgoorlie. ;)

[Pippin]

Hi Marty,
I just tried to get one out of an old head to post up to you. No wonder you had trouble as I couldn't shift it cold with a 1/2 inch drive. I'll try with a 3/4 drive if I have the adaptor but I don't fancy my chances.
Nick

[BMKal]

Hi Marty,
I just tried to get one out of an old head to post up to you. No wonder you had trouble as I couldn't shift it cold with a 1/2 inch drive. I'll try with a 3/4 drive if I have the adaptor but I don't fancy my chances.
Nick

They had trouble getting the old one out of the one I'm talking about too. Ended up having to heat up the head with an oxy torch. Would need to be careful doing this though - not too much heat.

[discorevy]

Onya Nick
Heat the head with heat gun around the plug area then cool the thread area of the plug with inox / lanox or similar, try to undo 1/4 turn then tighten / loosen, spray more and allow the lube to reach what will be the crusted coolant on the back threads to soften then undo back and forth till easy enough to remove .........worth a try
Meanwhile I'll have a search in the workshop

[Pippin]

Thanks Discorevy,
But no go, after 16 years it's not going to move on this one.
Cheers
Nick

[Nomad9]

Hi Guys,
Really appreciate your efforts here, Southerns have sourced one for me, it will be there tomorrow morning my wife will be picking it up for me. The thread is 25 X 1.5 and it is a conduit thread. I "borrowed' a tap from work today, the tap engaged and also cleaned the thread up a bit.

I'm now just contemplating options, rip the head off tonight and send it to M & D Auto Engineering tomorrow to install a "normal" core plug, cap style, which they have done on several TD5 heads before with great success, or get the plug tomorrow, try it in pressure test it and then plan the more permanent repair later on.

just out of interest these guys sort of gave me the idea that heating the head up wasn't the best idea, might promote galling. the other thing I have considered now in hindsight is leaving the coolant in the head, this might lubricate the back of the plug around the exposed thread I was trying to screw out this could of acted as a lubricant..... maybe.

Pippin, Thank you for your efforts, please don't wreck your own head on my behalf.

Cheers Marty

[Pippin]

Don't worry Marty that was an old cracked head I still have a good spare.

[discorevy]

Bit late in the day I know , but found one anyway , so if anyone else needs one!!! . Marty this is only my opinion but I'd save yourself the extra work , fit the plug using 567 loctite or similar
I wouldn't heat the head too much either but heat gun followed by lubricant draws the lubricant down the thread as it cools preventing the galling , I usually use lanolin based for that application.

[Nomad9]

Hi There,
Good sound information, I've got some 567 however I was going to use Toyota black sealant, this is the only product I have found that can stop the oil leaking out of the transfer case cover. Yeap know oil V water however a very good all round sealant.

The proof of the pudding will be tomorrow evening, I'll be in touch. Appreciate everyones constructive comments.

Cheers Marty.

[Nomad9]

Hi All,
Got the cad plated steel plug today from Southerns, not aluminium, obviously a design flaw that has now been rectified. The plug had good thread engagement, I put some Toyota black on the plug, wrapped two turns of PTFE tap around the plug and put another smear of Toyota black over the top of the tape. Plug has now been replaced and left until tomorrow night when I'll rebuild the rest of the engine.

Thanks for the advice and support, everything so far looks really good. I'll put the coolant back in tomorrow night and pressure test.

Cheers Marty.

[worane]

Gee, and I thought I had problems!
Well done all of you.

[morozka]

Hello! At my colleague in D2 the cooling liquid began to leave. Question: Is the coolant cap tightened to the stop, or is it turned off for a half turn? that is, when twisted to the stop, it should be weakened? Thank you!

[kelvo]

You must ‘tighten to the stop’.

Do NOT ‘weaken’ it.

[morozka]

Many thanks for the answer, friends !!!!