Bad core plug repair? Looking for opinion

Hello, new to etype ownership and first time posting in this forum. I recently had a couple core plugs replaced. The engine was recently rebuilt and plugs replaced prior to my purchase but they were leaking so needed repair. Anyways, took it to a local jag mechanic with 40 years experience. He replaced the plugs and sealed it with jb weld but he put it all around the plug. I didn’t plan to necessarily enter the car into any shows but this looks awful. Am I wrong? Ps. He also got a couple drips of weld on the painted frame rails.

Welcome to the forums Larry. That looks awful, have you tried chipping off the residue/excess. I have to say it looks a very unprofessional job.

Welcome to the J-L Forum Larry!

Yeah, hard to believe you had to pay someone to make that mess. I’m with you, it would bug me every time I saw it and I would see it every time I was under the bonnet.

Also not so great that he used Dorman plugs with ‘CHINA’ so prominently displayed.

Hopefully he will make it right but one gets the feeling he may not see anything wrong with it.

What you wanted…

What you got…

Big difference.

Thx all. Yeah my concern is doing more damage trying to remove the jb weld. I think anyway you do it some paint repair will need to be done. Really frustrated that these leaked considering the engine only has 500 miles after rebuild and they didn’t notice the plugs leaking during the pre purchase inspection.

If it was my car, I would clean up the excess JB weld with a dremel and sandpaper, and paint the area so the “repair” is indetectable.

The only alternative is to do the repair all over again, you would still have to clean up the excess JB weld though

This is the one reason I do all repairs myself wherever possible


I do a decent amount of diy but new to jags and had some other repairs being done (cool cat radiator & fans) so didn’t want to tackle this one. Just wanted to get it repaired and enjoy it.

Welcome Larry,
That’s a pretty shitty job that I would be embarrassed to put my name to, but pretty easy to remedy. If you are comfortable with working on “ordinary” cars, an E type shouldn’t generally give you any concern, especially given the help you can find here. If you are half way competent, you are probably miles ahead of anyone you are likely to pay money to do any jobs on your car, so just accept it as being part of the price of owning such an iconic vehicle. awg tony is spot on, if you don’t intend to show the car, tidy it up to the degree you feel comfortable with, and get on with life and enjoy it. If the car is a good, usable driver, you can make improvements as time, money and enthusiasm allow. Entirely your call.

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Has he fixed the leak?

If yes, just sand it back and paint it black.

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Maybe I’m wrong, but I get the impression from the photo that the plug is far from flush with the block - ie it hasn’t been driven in far enough. The JB Weld around the edge appears to be a fillet between the outside diameter of the plug and the surface of the block, and I’d be concerned that if I chip it away to clean things up it may impact the integrity of the repair. I use the work “integrity” here very loosely, as it doesn’t seem appropriate with such a lousy job…

Its hard to decide what to do about such a bodgy looking job, so I think I would need to clarify this matter with the mechanic as to why he did this…it is an E-type, not some cheap jalopy, and the appearance of that repair is unacceptable imo, so unless he can give you a rational reason as to why it has been done this way, then it really should be done again…properly this time

I would note its not uncommon on Jag and other engines to have corroded lips on the plug recess, and for new core plugs to leak (usually because of this

I clean them up with a rotary wire brush and flat screwdriver. I think if one was too bad, I would JB weld the corroded area, rather than slather it over the top

Bit of a hard call, but definitely ask the mechanic (nicely)

It looks like that one would be easy to redo, I use a self tap slide hammer to get them out, as bashing and prying them out is not ideal for the lip recess imo

If you do , get one without 'China" on it…imagine selling your car, and someone looks at that,bodgy looking job, “China” on the part…I would haggle and demand at least $1000 price reduction :slightly_smiling_face:

Thx I will talk to him today but honestly can’t imagine any excuse. Should I get input from another mechanics shop to have as ammo? Before I talk to him.

My best guess though is he couldn’t get the plug fully seated so he covered the edge with weld. He actually did the front two plugs on the car, the other one doesn’t look nearly as bad. (Pic below). I honestly thought all 4 were leaking as I could see a dried white line coming from the one closest to the firewall but he said that one was fine.

Also not sure why he didn’t use brass plugs, he didn’t ask me if I had a preference and considering all the other plugs are brass it’s now a mismatch.

Also keep in mind they dropped weld onto a couple painted spots inside the engine bay as well.

You dont need to talk to another shop, as you have had input from here, and I am sure they would say that is sloppy work

I have changed my mind.

This car is an E-Type, get brass plugs and have it done properly unless a really good reason can be advanced

maybe the apprentice did it, maybe he has got dementia, tell him you want it in Concours

I would do it myself if you can get at all the plugs

Yeah kind of hard to get to some of them. The shitty thing is I felt the car ran warm hence me ordering the cool cat setup and then noticing the plugs leaking which probably contributed to it on top of realizing the car was running way rich. He said when he drove the car the temp was sitting on the A in normal but during my drive home yesterday I got past the L, never got to red and it didn’t boil over but long story short I think it still isn’t cooling properly. Then again I live in Az and it was 104 yesterday.

I’m not defending the guy but
These cars are old and require TLC ( money)
They are awkward to work on (money)
Corrosion is often a problem ( more money
Parts are well suspect
What did he charge you
I’m thinking it’s a metric plug ,what he had to do the job
Is the leak fixed
As mentioned this is exactly why we do our own work
Quality Control
Cheap lesson


If the ambient temperature is 104 and you are driving around town, stopping at lights etc. that doesn’t sound bad or unusual. The engine temperature will vary and “L” is still part of Normal. On my Series 2 (also lives in Arizona) I only start to get concerned when the needle gets one needle width away from the Red zone. Even then, it has never boiled over, but I have pulled off the road to cool down on one occasion when in the middle of the Red and on a long uphill stretch in 100+ degree temperatures. I also suspect that my gauge may be reading a little higher than it should, but haven’t checked it - maybe because the delusion that it’s over-reading helps reduce my concern :smiley:

A leaking freeze plug will only impair the cooling ability of the system if it leaks sufficient coolant that you are significantly below capacity. If you check your coolant level regularly you’ll know that - note don’t fill the expansion tank or it will all just get purged onto the ground when the engine is hot. 1/2 full or less is plenty. One easy test that you might want to do is a pressure check on your cooling system. It will tell you if any leak is large enough to cause premature boiling due to lower than designed pressure.

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Totally understand that and knew there would be yearly upkeep but this just had a 50k mechanical restoration by the prior owner so a lot of maint. Issues should be deferred for at least a little while.

I have also since noticed that he left a 13 mm wrench laying near the vin plate, not really a big deal but then I noticed he left the ac pulley just lying in the bay. We removed the compressor as the ac clutch is getting sent out to be rebuilt. Wish I could upload the video but here are some pics. Unbelievable.


This says two things. Sloppy to leave any tools in the car, but maybe we all do that occasionally, BUT there is no place for a 13mm wrench on an E-Type. That says he’s using it as a lazy 1/2" wrench and that is sloppy in more ways than one. It will cause some unnecessary damage to the fasteners he uses it on.


Hi fellow Arizonan!! The level didn’t really drop before and I am now already familiar with the expansion tank filling when trying to figure this out before I took it in. :grinning: The temp was running one needle past the L which is what was getting me nervous. I also thought that maybe my gauge was a bit off, I know cool cat sells an updated voltage stabilizer but like you haven’t gone there yet. Only owned the car a few months.

Do you have stock rad/fans or upgraded ones? Also curious if you have a good local mechanic as I may be in the need for a new one.

My guess considering where I found it they probably used it to tighten down the battery terminal bolts.

That would irk me. My house had a previous owner window repair that looked just like that, ugly gray mastic plastered all around it. It probably took me 10 times as long to chip it all away as it it took for someone to bodge the repair.

It’s going to be a pain to get that off with the engine in the car. It would at least homogenize it if you shot it all with black paint, assuming the leak is stopped. If it isn’t I’d drill it, pry it out, and use one of the rubber Dorman cinch up stoppers.

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