Radiator plastic drain-petcock replacement

The little thing that we Brits call a radiator drain plug and people in the US call a "petcock" on my 93 4.0 XJ has started leaking seriously. It dripped from the pipe, whichever way I turned it, and attempts to screw it tighter didn't seem to help.

To my surprise it unscrewed easily.... and of course dumped all the coolant. Fortunately I had a large bucket underneath!

Only when I got it out did I realise that it was made of plastic (how stupid is that?) and needs only a quarter or half-turn to open and close..... and in fact when I removed it I found that the head, or tail of the thing (the bit at the inner end with the two prongs) had sheared off right where the O-ring fits! I suspect that it might have been weakened or cracked, and that my turning snapped that inner end off.

So I guess that little broken bit is lying at the bottom corner of the radiator (where I hope it can do no harm, as I can't see any way of getting it out).

First question: can I simply fit a new replacement? I don't think the threads around the hole are stripped: the plastic threads on the actual leaky broken petcock I removed look fine. I guess I won't know till I try...

Which leads to the next question: HELP!! It seems a new petcock is available from any auto parts corner store in the US, like NAPA, O'Reillys, etc , or online, for about $4. But over here in the UK they seem not rare but impossible to find. Even the dealers have to place special order and that costs a fortune. US suppliers, if they ship overseas at all, charge a minimum of $30-40, for an item that will fit in a Jiffy bag and go in the postal mail!

The most widely quoted part number is Dorman 61126. I have found the Crown number 83505381, and the Jeep p/n is 4773 259.

So... HELP! Is there a kind member who would be prepared to do me a favour and put one of these into a little padded envelope and send it to me in UK? I'd happily pay all the costs - PayPal is probably easiest. Without a new petcock my Jeep is pretty well unusable, so I am in urgent need! Please PM me if you are willing to help this Jeep owner over here in Scotland.

If I can repay the favour by sending anyone any similar hard-to-find small parts from the UK, I'm happy to do so - though I'm not sure if we have anything that isn't available in the US anyway.....

I live in hope of a helping hand!

Check www.RockAuto.com
They ship outside the US, and usually have good (at least for this market) pricing.

Wow, okay, yeah, $30 postage. Scratch that.

Yes, hubs.... now you know why I feel pain!

Rock Auto are always an essential online reference for me, especially for finding alternative parts numbers, and I have occasionally used them for high-value small-to-medium size parts like wheel hubs for my Pontiac. But for tiny items the shipping cost is outrageous, and large parts like suspension arms or body panels are almost impossible to ship internationally.

I still live in hope....!

I have no clue as to what you guys use for pipe fittings over there, but could you source a plug in that size instead of the chintzy plastic drain?

Have you tried actually getting Rock Auto on the phone and asking them about shipping? Alot of websites give flat rate shipping quotes. One that comes to mind is Rusty's. Their website says everything shipped to my door mostly is like 40 bucks! Give them a call and its alot cheaper depending on what you are buying.

This will easily fit in a small flat rate box...US$16.95. If you can't do better than that direct, send me a PM. I'll pick one up and mail it to you.

I call it a crappy POS Chrysler Drain Plug. I figure they think anything older than five years is going to fall apart anyway. Also that most owners are not going to flush thier coolant until the drain is out of warranty. Then it's your problem. A plug is probably better than a butterfly valve.

I have a Pet XXXX...but that's different story. Censor away, they'll know!!

Thanks to all - especially Brown Dog - for replies so far. I'll see if I can get Rock or Rustys' to quote a sensible shipping rate, and post again if I need to take up that kind help-offer.

I did think about alternatives, like a plug to shut the hole off completely (I can always drain via lower hose when I need to). But I saw some forum post that said it's a weird thread size. The spares websites suggest the thread is 5/8" - 18, whatever that is. I can't see what the thread is like inside the hole of the radiator tank. Is it metal (aluminium?) or is there a plastic or other threaded insert?

If anyone knows for sure what size/thread or spec of metal (brass?) drain plug would fit, I'd be willing to simply stop up the hole if that is likely to be more reliable than fitting another flimsy piece of plastic. Any wise advice welcome!

If your radiator is older, you may want to consider replacing it.

More than what you originally thought you would have to do, but is an option if you could source a replacement radiator in the UK at a reasonable cost.

And in the future, change coolant by dropping the lower radiator hose. The petcocks are a piece of crap and I never touch them.

I feel your pain, i unscrewed an XJ's petcock and had the whole fitting and all fall right out of the radiator. I used most of my profanities on that one

not sure what you've got going on in the UK but here I would take what you;ve got left of the plug to a hardware store and see if you can match it up, it's most likely what we call over here "tube thread", commonly used on AN type fittings and 45° flared tubing connections.

i used a factory bumper/crossmember bolt to plug on my dd, 2 years with no leaks

What about using a little epoxy on the old one and letting it cure in place before adding coolant?

what do you do for radiator drains over on your side of the pond?

Over here they are mostly pipe thread, and an off the shelf part (same thread that you'd use for fitting iron pipes together.)

I'd be tempted to retap the hole for whatever you all use for the same application, and buy a generic universal petcock from your local auto parts store.

I do not use that POS valve, used it once and it makes a mess and a PITA. I just disconnect the lower hose.

br1anstorm said:

Thanks to all - especially Brown Dog - for replies so far. I'll see if I can get Rock or Rustys' to quote a sensible shipping rate, and post again if I need to take up that kind help-offer.

The spares websites suggest the thread is 5/8" - 18, whatever that is. I can't see what the thread is like inside the hole of the radiator tank. Is it metal (aluminium?) or is there a plastic or other threaded insert?

If anyone knows for sure what size/thread or spec of metal (brass?) drain plug would fit, I'd be willing to simply stop up the hole if that is likely to be more reliable than fitting another flimsy piece of plastic. Any wise advice welcome!

Click to expand...

5/8-18 refers to the bolt diameter (5/8") and threads per inch (18).

Lots more useful advice, for which many thanks. An inspired idea from birchlakeXJ, too. A late-night session with Mr Google turned up trumps. I went browsing for "XJ radiator...." and guess what turned up on eBay. Some chap here in UK selling a brand new OEM radiator, but for a LHD vehicle so it was being offered at a ridiculously bargain price. It is said to be made by Valeo, so might have been for a Euro-spec vehicle. I pounced, and bought it at once. With luck it will be a worthwhile replacement for my 20-year old original. Now I'm off to hunt for a new set of hoses, and meanwhile I think I will just find a suitable threaded 5/8" bolt to plug the drain hole in my existing rad. We haven't solved the problem yet, but it's looking a bit more promising than a few days ago!

br1anstorm said:

An inspired idea from birchlakeXJ, too.

Click to expand...

I am good for one inspired idea per year. See you all in 2013. :viking:

New radiator just makes sense here if it's old. And you say it's original and that qualifies. A 20 year radiator owes you absolutely nothing and is probably going to fail very soon anyways, so with your score of a replacement, you should be good for another 20 years!!

I don't touch the drains for this reason, just pull the lower hose. You could possibly just try to drain the rad and JB weld it in place.

The story in this thread ain't over yet. Life with an XJ is full of highs and lows. I now need a different kind of advice.

I thought I'd benefited from a minor miracle, finding a brand new OEM (made by Valeo) radiator over here in UK that would fit my LHD XJ. I had started flushing and removing the old one - and in doing so discovered that the cooling fins were in a bad way. All the more reason for putting in a replacement.

So, the new one arrived, and yep, it's all shiny and the correct part. It was in its original box, but not brilliantly packed (just a few bits of polystyrene, cardboad and shredded paper), so the rad could slide around loose inside. I checked it over. Disaster.

Somewhere along the way from factory to warehouse to parts dealer to me, the box had obviously been thrown or dropped on its end, and the left-side end of the rad, where the petcock is, had been banged (on the floor?). I found that the plastic drain-petcock (a different design from the one on my vehicle) which fits into a little plastic pipe-shaped mounting on the rad, had been stoved in. The petcock was in three pieces, wedged into the 'pipe', which was cracked, and the plastic moulded lugs which should hold it in place on the inner end of the 'pipe', inside the tank, had sheared off.

Despair. Finding another new rad for an LHD XJ over here is almost impossible, and an order from the US is totally unaffordable.

So - my question. How can I rescue this new rad and make it usable? The obvious solution is somehow to seal up, permanently, this hole at the bottom of the new rad where the drain-plug should be. I'd like to know how others have done it, because I can see some problems.

• it's all plastic, not metal, so no scope to seal up the hole by normal welding or brazing;
• there is no threaded hole, so I can't just fit a bolt and washer/O-ring (as I have done temporarily on the old, original rad);
• the 1" plastic pipe that projects out of the bottom corner of the plastic rad moulding and into which the petcock would fit, is cracked, and anyway has a little drain-pipe tee'd off it, so I can't just clamp a hose over it and then find a way of clamping the hose shut;
• the whole piece (each side, or end 'tank' of the rad) is some kind of hard black plastic moulding. Most epoxy and superglue won't bond well to such material, so I'm not sure if I can glue a "bung" or plug into the hole which will withstand the heat and pressure.

I'm really reluctant to junk an otherwise brand-new radiator. But I need to find a 100% sure way of sealing up the hole which that b****** petcock was supposed to fit into.

Help!

I think XJ's were sold in Germany as well, might be a source of replacement parts there? I know I've seen taillights on German eBay (and have been tempted...)