Danger turning radiator petcock too tight?

[paulri]

Is there a problem if I tighten the petcock too much--as in stripping the thread, etc.?

I've been leaking all day after draining & filling the coolant. Each time I am hand tightening it a bit more. It feels like I have it tighter than it was when I twisted it off. I have looked and I'm pretty sure I have ruled out a leak higher up than the petcock--everything else I touched was dry. I have felt the hoses where they connect with the radiator cap and the overflow container, and they are dry as well. They are not cracked, and I couldn't find anything leaking from the hoses, so I can only assume the petcock isn't tight enough. The puddles are all right below the petcock.

Another option that I've come across (to simply twisting tighter and tighter) is to put on teflon tape. Obviously with a radiator full of coolant that will be complicated. Is there a way to plug up the duct that it pours through, with my fingers, while someone else wraps teflon tape around the petcock? Or is teflon tape simply an option to remember next time?

Honestly its not that much--I still have some left in the overflow compartment, and the car is not overheating at all. Its just frustrating, seeing a small puddle every time I go out to my van.

 

[SZR48207]

If it seals with gaskets or o-rings then you only need to tighten it enough to create a seal. If it's made of plastic then be careful as well.

 

[TheLawnRanger]

I would run it a day or two and keep a close eye on the situation. You may have gotten coolant somewhere that keeps dribbling. It may stop on its on if there is still coolant in the resevoir. If not, take it to a mechanic that might be able to set your mind at ease or fix the problem if there is one.

 

[4WD]

Had enough of this plastic fail on me where I just either take a hose clamp off … or use my super syringe to rotate new coolant into the top cap periodically …

 

[John_K]

I had this happen once, finally figured out the petcock had a hairline crack and only leaked while under pressure.

 

[KneeGrinder]

Negative on the Teflon tape, your "Petcock" lol, has an oring, orings do not require an extreme amount of pressure to make them seal. If you replace, which I would suggest, put a little Vaseline on fingers and lube it before installing it on your Petcock. Should fix it right up.


The kindergarten censor is slaking...

 

[BigD1]

If it's the push-in plastic type, don't over tighten it because the stem will break, and you will be holding the knob.

Best thing to do is just replace the petcock before it does break because they are a royal PITA to get out. All you have to do is unscrew it, and if it's not broken it should pull right out. Get a big pan to catch the antifreeze, and just pour it back in after you make the repair. Petcocks are about $5 out the door.

 

[demarpaint]

I remove the lower radiator hose, it makes life easier.

 

[Lubener]

Originally Posted By: demarpaint
I remove the lower radiator hose, it makes life easier.

Always. I never touch these plastic petcocks anymore.

 

[nobb]

Originally Posted By: Lubener
Originally Posted By: demarpaint
I remove the lower radiator hose, it makes life easier.

Always. I never touch these plastic petcocks anymore.


Those petcocks take forever to drain and often times you'll get a better drain from just using the lower hose.

 

[Sayjac]

Used them on Nissans, Toyotas, Hondas, never had a problem. Generally have o-ring(s) on them that seal before they hit the stop point on tightening. And ime they can either be completely removed which helps them drain faster, or just turned until AF comes out the drain tube.

Of course if one overtightens them as the topic states, then there could be an issue. IME with hand tightening shouldn't be an issue.

 

[CorvairGeek]

Originally Posted By: Lubener
Originally Posted By: demarpaint
I remove the lower radiator hose, it makes life easier.

Always. I never touch these plastic petcocks anymore.


+2

Had one spit out (broke, internal portion still in the radiator) in the Costco parking lot. The trail went so far I didn't follow it. It had been a long time since I had serviced the car. I now carry a replacement in the the glove compartment(s), so it will never happen again.

 

[Chris142]

We recommended that our customers don't ness with the drain plug. Every manufacturer is different and if it breaks you may not be able to find a new one. Pull a hose.

 

[FCD]

They're useless!!
You get more coolant out by disconnecting the bottom radiator hose and it's safer.
Imagine you screw up somehow, which is easier to get, a particular petcock for your particular radiator, or a hoseclamp??

 

[4WD]

Hose is the popular choice here … but does the OP still have a leak?
It might be best to leave it alone a try a radiator stop leak at half of recommend dose … once it seals something that low in the system, good chance it will stay sealed …

 

[paulri]

Yes, I went out today and saw that I still have a leak. In the 30 seconds I was below my car, I saw two drops fall. I don't see how this much could just be residual stuff that spilled out when I was changing the fluid.

I have found two parts stores that say they have one that is an exact fit, so I'll get one and then put it on later today. I topped off the overflow again--it is obviously draining, but as I said before, not enough to cause me to overheat. The fact that I believe it is draining slower, as I've tightened the petcock, makes me think that really is the problem.

If the new "radiator drain plug" doesn't do the trick, I can follow up 4WDs solution and try some stop leak.

Since you are talking about an o ring, now that I think about it, I recall seeing black rubber that looked like it formed one (it was cut), about wide enough to go around my little finger--it was floating around the coolant that I was draining. Perhaps that was the oring? I just thought it was engine gunk that fell down into the drain pan. When I take out the old one I'll check and see if there is one still there. Regardless, I'll try the new drain plug this afternoon and report back.

 

[Drew99GT]

You simply need a new o-ring, most likely. You can take the old one to Ace Hardware and get a new one. In fact, on our 2007 Impala, for whatever reason, whenever the petcock is opened, I always get a new o-ring as it almost always leaks after opening.

 

[Mr Nice]

Spend the $1 and install new O-ring.

 

[paulri]

Interesting. I inserted the new drain plug, and saw that the old one still had a black ring around it, so it must not have been the o ring that I saw in the old coolant yesterday. Regardless, I put in a new one. I'll see if that does the trick or not.

I had tightened it so hard that I thought I had to use pliers to get it to come loose, but in the end I was just able to twist it off. The new one I tightened hand tight, but not nearly as tight as the one I got loose. And next time I'll look at the lower hose. Both my cars are done now for coolant drains, the Sienna will get it flushed at 200K, the Civic is due in 3 years, but when I do this, I'll look at removing the hoses. A lot of folks here are saying that is how they do radiator drains.

Hopefully that does it!

 

[BigD1]

Glad you got it fixed. Coolant leaks get expensive, and overheating is a concern if the coolant level gets too low.

Wise choice to replace it because that plastic threaded stem can break just sitting there.

Had a petcock to go bad the other day, and the radiator is only 25 months old. Threaded stem must have been barely holding the o-ring against the drain because when I went to take it out to replace it the knob came off in my hand. Never have used the petcock on the radiator since new.