12 replies to this topic

[MikeJE]

Has anyone had any problems with core plugs in a 998? I have had three blow out now, two from the same hole. I put sealant in and then give them a good bash to splay them. The last one lasted 60 miles before blowing out rather dramatically just after exiting the M25 (with the suicide breakdown lanes!).

 

Has anyone else had a similar problem?

 

Best wishes and stay safe everyone

 

Mike

[E23TFD]

Make sure the cups and bore are clean. Use some Loctite 638 or 648 apply to bore and also to cup and then seat. Make sure clean and dry.
That’s an option, alternatively I’m sure either options will come your way.

[MikeJE]

Thanks E23. I have ordered Loctite 638 and will give it a go. I have seriously cleaned the bores each time but will have a try with a wire brush this time.

 

Best wishes

 

Mike

[RooBoonix]

Make sure you don't over splay them, if you hit them too much they just dish the opposite way and any outwards force is lost.

 

However, with a bit of 638 on them I don't think they'll go anywhere anytime soon 

[MikeJE]

Make sure you don't over splay them, if you hit them too much they just dish the opposite way and any outwards force is lost.

 

However, with a bit of 638 on them I don't think they'll go anywhere anytime soon 

 

Many thanks - fingers crossed!

 

Best wishes

 

Mike

[Spider]

In addition to what the other guys have suggested, before fitting them, measure the size of them, just to be sure they are big enough to start with.

 

To clean everything before I fit them, I give the holes in the block a bit of a go with a wire wheel in the drill, then get a scriber to get right in the corner, finally cleaning with thinners. I also clean the new plugs with thinners too.

 

When it comes to expanding these type of plugs, I use a ball pein hammer, starting in the centre of the plug, just hitting it enough to flaten that part of the plug, then work out in a spiral towards the edge, so that when I've finished, just about the whole plug is flat. Can't say I've ever had an issue doing them this way.

[weef]

Let us not forget the whole principle of the core plug. They are designed to come out if the coolant freezes, admittedly not too common nowadays , but thats what they are for. Loctite 638 is maybe not the best for this job. First off you will have to decide why the core plug keeps coming out. Sort this mechanical problem first and then refit the core plug. A more appropriate sealer might be something like Dirko HT. 

Why waste Loctite , you might as well weld them in.

[MikeJE]

Let us not forget the whole principle of the core plug. They are designed to come out if the coolant freezes, admittedly not too common nowadays , but thats what they are for. Loctite 638 is maybe not the best for this job. First off you will have to decide why the core plug keeps coming out. Sort this mechanical problem first and then refit the core plug. A more appropriate sealer might be something like Dirko HT. 

Why waste Loctite , you might as well weld them in.

 

Many thanks weef. The problem is that I cannot work out why they have come out! And I cannot find any plausible explanation as to why this may happen either.

 

It is not overheating and is running properly, but this is the third one to go awol. I have used Minispares' replacements but this time have used one from Minisport, which seems to be 0.1mm larger in diameter. I cannot see how that could make any difference, but with the Loctite I am keeping fingers crossed. 

 

Best wishes

 

Mike

[sonscar]

The purpose of core plugs is to enable the casting of the block,the freeze plug term is anecdotal?.This is just my view.Steve..

[weef]

I take it you are fitting the correct type of core plug. There is the domed type and the cup type. With the domed type select the correct size and fit it into the hole, there is a small lip that the core plug should seat on. This type has to sit square on this lip to fit correctly. Apply a small amount of sealer, whichever type you decide to use, and with a soft drift expand the plug by hitting it in the centre. It does not need a huge knock just enough to secure it. 

If it is the cup type the fitting/selection process is similar but this time using a suitable sized socket drift the plug into the hole, keeping the plug square.

The hole prep is the same for either type. Clean up as best you can, if there is space a cup type wire brush in a drill is good if not emery cloth stuck onto a small piece of wooden dowel will do nicely.

As with everything these days it appears that there are some poor quality parts out there so be careful with your spares sourcing.

[MikeJE]

Thanks again weef. These are the domed ones. I see you suggest they don't need a huge knock, which I had assumed to be the case, although others say they hit it until nearly flat. All those I have seen previously have still had a dome shape, but with a concave bit in the middle where they were knocked in. The new one is in now and I will try running the car locally to see if it stays in (though the last one came out after a 60 mile run...).

 

I used Minispares replacements before (and one of those remains in situ). I have tried one from Minisport this time, with the Loctite.

 

Really hope it works as I am planning on going to the Mini Cooper Register event at Beaulieu next weekend.

 

Many thanks for all your comments - very helpful as always

 

Best wishes

 

Mike

Edited by MikeJE, 06 June 2021 - 10:47 AM.

[PoolGuy]

Are you using steel or brass plugs? 

[MikeJE]

Are you using steel or brass plugs? 

 

Steel I think - these from Minispares http://www.minispare...px|Back to shop

 

Not sure I have seen them in brass

 

Best wishes

 

Mike