today didn't go as well as yesterday Yesterday I replaced the cross-over section and bypass hose in my cooling system. Pretty simple job, buttoned everything up, wiped down the excess coolant that sprayed all over the underside of the engine and called it a night. This morning, I notice a small puddle of coolant under the car just below the drain. I jacked it up and noticed some weeping from the drain so tried to tighten a bit more and got may 1/8th of a rotation then the drain snapped off.

What's the easiest way to remove the broken section without taking the radiator completely out?

 

Can't really tell what I'm looking at here. Is it that the phillip's head of the drain plug snapped off and the rest of it is inside the radiator? Is the petcock flush with the radiator? Perhaps, since it's a plastic piece, you could try driving a small screw on its center just enough and then pulling on it with some pliers. Maybe a reverse thread screw would work best since that would allow you to unscrew the petcock out before pulling on it with the pliers?

You also have to deal with access and visibility. Do you have access to a lift to make your life easier or is it all down to jack and jackstands?

As for the replacement petcock, you can buy the Dorman 61138 for $3 from Rockauto, it's a direct replacement. https://www.rockauto.com/en/moreinfo...=12518&jsn=586

 

+1 hoping its plastic. Glandaniel has a good question there. Can you please say what material is left in the radiator and what, as far as you can see, is its profile? Does it protrude At all?

Will it be better to loosen the lower hose to drain the radiator? Just afraid it'll be a real headache to extract the plugs reminenants and have to deal with a few gallons of coolant shooting out.

John

 

I am also wondering which bit I'm looking at.

The OE drain plug is plastic with a large X head:




Awkward to access and working on a broken one isn't going to be easy without removing the radiator.

It's been a while since I worked on an XK8 but I think the tapping in the radiator is a metal insert. If I'm right, you can be quite brutal with the remains of the broken plastic drain plug as it's a lot softer material.

Graham

 

giandaniel, yes - it's the plastic phillips head (picture is of the backside where it snapped off) and remainder is still in the radiator probable flush with the radiator shell. I was going to try and use a phillips screw driver and try to tap it into the plastic with a rubber mallet - may be able to get it that way. I only have a flor jack/jack stands but may see if I can get access to a lift

John - I was thinking about draining from the lower hose, then less of a mess once I start trying to extract the plug

Graham - hoping the insert is metal - I installed this radiator a few years back so not sure as I didn't have to mess with the drain plug at that time

Really don't want to remove the radiator but may have no choice. Will update once I get replacement plug and begin the task

 

Yet another plastic component to despise. I will never attempt to remove the factory one from my wife's 2006 XK8. So much safer to just pull a radiator hose or two and pump out the coolant with a $5 Harbor Freight hand pump....

Good luck and keep us posted on how it turns out....

 

a better shot of what I have to deal with. I did remove the gasket so that there would be more seepage - maybe by tomorrow evening when I get home with the new drain, the radiator will have drained enough to make it less of a spray when I take the broken plug out

 

Two possible approaches:

1. cut a groove across the perimeter (arrowed in red) then use a small chisel and a hammer to tap it anticlockwise
2. drill a hole in the centre (arrowed in blue) and use an "easy out" extractor to unscrew the remains




I'd go for option (1) first as the quickest.

Good luck.

Graham

 

we you can remove the busted drain plug without removing the radiator!!! took about 3 hours but a combination of using speed extractor and then a straight blade screw driver similar to Graham's method 1, it is removed, new installed and filled- now just waiting to cool down so I can check level again.

Graham - method 1 wouldn't work as that area is the old gasket - so once it was removed the plug was too far into the radiator to cut a groove.

I started with a 0 speed extractor attached to a 1/4' socket on an 18" and 12" 1/4drive socket extensions with one of those attached to my cordless drill. I ran this over the subframe and to the plug. This started a pilot hole, then I went up to a size 1 and then size 2 extractor. The extractor would not catch enough to rotate the plug as the plastic just kept breaking off. Once I got a decent hole, I was able to force the rotation with a screw driver as Graham suggested. I will check level again tonight and then double check plug tightness and level again tomorrow afternoon but consider this resolved

Here's the broke plug.

 

Well done....

 

Checked level before I went to bed last night - had to add about 1/4 cup to top it off, saw no drips under the car. This morning, I pulled her out of the garage and went to look where she was parked for any signs of leakage - not a drop so drove her in to work. Nice ride in, temp hovered around 199-201 and only got to 206 1 time sitting at a red light. Will see how she handles today's afternoon heat - supposed to be near 100.