I had to leave a lady in the car while I was getting my health certificate. This took a lot longer than expected as the doctor had to deal with a few emergency patients. The lady stayed inside the car with the car parked and the engine on for a good 2 hours.

When I finally got back into the car I noticed the coolant temperature at 220 ºF. It's was a hot day. I took her home and then I returned to mine. As I was driving back home I got an random low coolant light. But it came and went so I expect the coolant level to be at about mid-tank. I decided to drive a bit further and made it to my house. It was only about a mile away. Once home, I popped the hood to see if I could find a leaking hose. Nothing, but as I went to the passenger side I noticed coolant leaking from the bottom right corner. I jacked the car up to confirm the leak wasn't coming from the upper radiator hose or the supercharger pump. Well, when I stuck my head down there I noticed the leak was coming from the radiator drain plug. I tried tightening it by hand but as soon as I touched it the head snapped off flush with the radiator. I checked my spare parts and luckily I do have a brand new drain plug.

Now all I need to do is find a way to remove the one I have. I was thinking, instead of trying to drill or pick-off the plug. Could I heat up a flat head screw-driver until it is red, jam it inside of the drain plug, let it cool and then just unscrew it? The plug is plastic. I think it should work?

 

I like the way you think! Not a straight shot on the plug, but perhaps a heavy long screwdriver would hold the heat long enough to melt into the plug from underneath . A past post indicated these are a std. pipe thread and may find at a HELP section board at store similar to Auto Zone. GOOD LUCK!

 

Judging by the access of my radiator drain plug on the ’02 XKR, you won’t have enough room to monkey around with a hot screwdriver unless it is just 2 inches long, at most. Even then, there’s no room to whack the hot screwdriver to imbed it into the plug. It’s not going to go just in like it’s cutting into soft butter. The plastic is very brittle You are likely to just bugger-up the radiator threads if the remaining plug is forced to any degree.

I think you are better off the old fashioned way; with a compact 90 degree drill and drill out the remainder of the plug, or enough of it to get an e-z out screwed onto it .


Z

 

Damn the plastic parts throughout these cars' cooling systems....

I agree with carefully drilling it out. Good luck and keep us posted....

 

The main reason I am advising caution is that this job can get a lot more expensive once the threads on the radiator itself are damaged. Those threads are just as old as the drain plug’s, and have gotten pretty hot, maybe compromised, during the the last adventure with the car idling for a couple of hours. So taking it easy on them would be my top priority.


It is unfortunate that many or most radiator tanks are plastic these days. But lasting 20+ years is pretty good.

Z

 

Actually, my radiator is 2 years old. I replaced it in 2020 because it developed a hairline crack and was leaking. I replaced it with the Nissens radiator and immediately noticed that the drain plug that came with was different looking.

I decided I am going to remove the radiator this weekend if the weather allows it. I feel that way I am less likely to damage the radiator.

 

That is surprising that a 2 year old Japanese radiator couldn’t better withstand some modest overheating .


Z

 

if you have a pair of 90degree needle nose pliers - you can use those to try and grip on to the remaining piece of the plug and try to unscrew or as I had to do a few years back - use a speed extractor to attempt removal

https://www.jaguarforums.com/forum/x...solved-220501/

 

I could not grip the remaining piece of the plug with the 90° pliers as it was broken flush.

I removed the radiator, drilled out the plug just a little bit, then used the pliers to grab the new wall that I created and drove it out. Threads were unharmed. I installed the new plug and re-assembled the radiator, fan shroud, refilled with coolant and burped the system. All done within 3 hours.

Problem solved. Removing that plug without removing the radiator is a fool’s errand.

 

Your comment on finding the expansion tank half full worries me ....it should be right up to the top of the filler hole or the atmospheric tank does not or is not working right. Having just been stuck in an 8 mile traffic jamb I can tell you that these cars do not like to idle too long ..I put it down to the water pump not rotating fast enough at idle.

 

I didn’t find it that way, that is what I was expecting to find given the intermittent low coolant warning. However, what I instead found was a leak from a broken radiator drain plug.

 

For anyone needing to drain any amount of coolant from their system in order to effect a repair (hose replacement, thermostat replacement, cooling outlet duct replacement, etc.), given the age of these cars now you are much better off just pulling one end of an easily accessible coolant hose (with a catch basin underneath), letting it drain as much as it will, and then pumping sufficient coolant out with a cheap hand siphon pump in order to carry on with your repair. Attempting to open these baked and brittle plastic radiator drain plugs is just asking for trouble....

 

Agreed Jon, but here’s the interesting bit, the drain plug broke while driving, not while doing any repairs. That’s what still does not make much sense.

 

Part being not that old tends to make one believe the part was not up to specifications, quality sub-standard.

Z

 

Agreed, I replaced it with an OE plug. But, the plug that was on there came with the Nissens radiator, which makes me question the quality of that radiator.

 

Nissens parts are typically good quality. But a plastic radiator drain plug, regardless of who made it, is simply a design flaw that we all live with....