Leaking antifreeze

[jeepzj]

Had my leaking water pump replaced by the dealer....also replaced original hoses(73K miles). No more leaking water pump. A couple of days later I notice a little antifreeze on the driveway. I figured out it was leaking from the hoses(clamp to upper rad, clamp to water pump and clamp to thermostat housing were loose). Tighened all 3 one full turn and no more leaks for 2 weeks. Well, the last couple of days the hoses start leaking again. These past few days have been really cold here(down to 0*-10*) and that's when it started. If it's not too cold in the morning it will not leak. I checked the clamps again to make sure they didn't come loose and they didn't. I know this because I marked where the screw on the clamps stopped originally and all 3 did not move. So why would antifreeze leak when it's really cold outside? By the way, once the engine warms up the leak stops...I guess that's because the thermostat opens and releases pressure from the radiator and hoses once it reached 195*?


Thanks.

 

[Kestas]

I doubt it's from the tightness of the clamps. A healthy cooling system actually needs very little clamp force to hold pressure. The rebuilt water pump probably has a lot of pitting at the connection surfaces. Once I even bought one that was perforated from corrosion!

 

[Spector]

Yea, in cold temsp the o rings may contract permitting coolant to seep by. Agree, probably the pump in some manner

 

[jeepzj]

quote:

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Originally posted by Kestas:
The rebuilt water pump probably has a lot of pitting at the connection surfaces.

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Pitting at the connection surfaces??? Sorry, what exactly does that nmean?

The water pump(weap hole) doesn't leak, it's leaking at the hose connections. Why does it leak only when it's really cold out and not when it's above let's say 20*?

 

[7TFord]

Hoses will leak when cold due to the contraction of the rubber. When hot everything swells and seals better, as you say. I'd try tightening the clamps a little more first. If that doesn't stop the leak I'd remove the hose and clean all mating surfaces (inside the hose also) with an alcohol or paint thinner to remove any grease and then reassemble. If the clamps are originals you might consider new ones.

 

[jeepzj]

quote:

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Originally posted by 7TFord:
Hoses will leak when cold due to the contraction of the rubber. When hot everything swells and seals better, as you say. I'd try tightening the clamps a little more first. If that doesn't stop the leak I'd remove the hose and clean all mating surfaces (inside the hose also) with an alcohol or paint thinner to remove any grease and then reassemble. If the clamps are originals you might consider new ones.

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I'll try that thanks. The clamps are no longer the originals or even the same as the originals. The dealer decided to use the screw-on clamps instead of the self-clamping oem design.

 

[Stooge]

If it is the hoses leaking past the clamps, and the hoses are new, definely take them off and clean the insides. I always wash new hoses with detergent to remove the oils used in the molding process. The oils allow the hose to come out of the mold great, but also allow movement around on your waterpump nipples (and leak) regardless how tight your clamps on. The hoses should be (almost sqeaky clean) and require some force to slip on the radiator/water pump nipples. Ideally, the hoses would hold pressure without the clamps.

 

[jeepzj]

quote:

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Originally posted by Stooge:
If it is the hoses leaking past the clamps, and the hoses are new, definely take them off and clean the insides. I always wash new hoses with detergent to remove the oils used in the molding process. The oils allow the hose to come out of the mold great, but also allow movement around on your waterpump nipples (and leak) regardless how tight your clamps on. The hoses should be (almost sqeaky clean) and require some force to slip on the radiator/water pump nipples. Ideally, the hoses would hold pressure without the clamps.

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That makes sense thanks. I will try that myself or have the delaer do it since they installed the hoses originally.


Thanks all.

 

[oilrecovery2003]

" The clamps are no longer the originals or even the same as the originals. The dealer decided to use the screw-on clamps instead of the self-clamping oem design. "


Those screw on clamps are a lot better then those piece of **** OEM orig clamps.

 

[jeepzj]

quote:

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Originally posted by Kestas:

There are some mechanics that actually favor spring clamps for cooling systems. For one, it prevents over-tightening the joint. And now it appears that it can compensate for thermal shrinkage/expansion.

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I agree. I never had a leaking problem with hoses when I had the OEM self-clamping design. I will tell the dealer to clean all mating surfaces including the inside of the hose and use the OEM clamp design again.

 

[XS650]

quote:

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Originally posted by Kestas:

There are some mechanics that actually favor spring clamps for cooling systems. For one, it prevents over-tightening the joint. And now it appears that it can compensate for thermal shrinkage/expansion.

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I've seen a lot of over tightened worm screw clamps that had smashed the life out of the hose. If you tighten them too tight they damage the hose and smash it down so that it can't expand and contract as much. The people that do that would definitely be better off with spring clamps.

I'm in the process of replacing all the radiator and heater hoses on my car because the PO overtightened all the screw clamps and squished the life out of otherwise good hoses.

Here are some interesting clamps. Worm screw with built in springs to maintain tension
http://www.breezeclamps.com/ct.htm
I was going to use them until I found out they cost about $5 per clamp.

 

[cousincletus]

Cold water leaks are pretty common on big trucks and heavy equipment. This isn't a big deal as long as you check your fluids regularly. IMO, the spring clamps are better, but the screw type are usually easier to work with in tight locations. Try tightening when the engine is hot. The rubber will squeeze a little easier. Just don't overtighten.

 

[XS650]

quote:

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Originally posted by cousincletus:
Try tightening when the engine is hot. The rubber will squeeze a little easier. Just don't overtighten.

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The trick is developing the proper amount of self control while tightening a hose clamp on a leaky hose so you don't smash the life out of the hose.

 

[Kestas]

Not always. On another forum people are experiencing coolant leaks in cold weather. This may be due to thermal shrinkage of aluminum and loss of clamp force.

There are some mechanics that actually favor spring clamps for cooling systems. For one, it prevents over-tightening the joint. And now it appears that it can compensate for thermal shrinkage/expansion.

 

[Cressida]

Some of you are outdated on your understanding on hose clamps. In almost all cases the spring loaded type of clamp is preferred. It allows thermal expansion of the hose when needed whereas the screw worm-drive clamp compresses the hose material when hot and then when it cools it looses part of it's clamping force as the hose contracts. For better understanding go to the Gates WWW site to see info.

I do have to confess that I've put a double screw worm clamp on a radiator hose to stop a cold wheather leak as is described in this thread. However I believe the spring band clamps (not the wire ones) are best , I've ordered a new hose and will clean it up and use the spring clamp when I install. Perhaps cleaning up the new hose ends with a detergent and checking over the connector ends makes a big difference too.

[ January 24, 2004, 10:15 AM: Message edited by: Cressida ]

 

[labman]

Co efficient of expansion, degree C.

aluminum--------23 x 10^6
brass-----------18 x 10^6
cast iron-------11 x 10^6
stainless steel-19 x 10^6
Plastic---------likely higher

Naturally everything varies some depending on the grade. For the last 40 years, I have been throwing away the wire types and replacing them with stainless steel screw clamps. The only repeated problem I ever remember was on the heater core of my 92 Grand AM. I don't remember, but I think it may have been plastic. This thread has me wondering if what worked so well so long with conventional materials and lower rates of expansion, isn't working as well with more and more plastic and aluminum. I don't have a figure for plastic, but believe it is much higher than metals. I appreciate the many benefits of plastic, but it does have some drawbacks. One of those is molded surfaces sometimes are harder to seal because of mold lines. I can't imagine the wire style have improved enough to trust them. Perhaps when my 02 Cavalier needs for new hoses, I should look at some of the newer spring styles.

 

[jeepzj]

Went to the dealer yesterday about the leak. They tightened up all the clamps then pressurized the system and found a small leak around the pep-cock seem which is on the passenger side of the radiator. They replaced my radiator under warranty and they said no more leaks....we'll see. They used the same screw type clamps because they said they don't even carry the self-clamping design anymore due to many leaking complaints by customers. Hope this time they are tight and won't leak again.

Question:
I was wondering, can you damage the upper raditaor nipple if the clamp is on too tight? How delicate is that?

Thanks.

 

[ZR2RANDO]

Something else to keep in mind. I have noticed that lots of times the parts houses have the hoses hanging up by a plastic wire that is threaded THROUGH one end of the hose, it pierces the rubber hose in 2 places (usually close to the end but sometimes rather far back..pierce spot equals leak!!!). I had one of those hoses that was hard for me to place the clamp far enough back to seal the hose before those pierce spots, I eventually had to cut off about 1/2 in of hose and then stretch the hose a little tight in one of the pre-formed curves to make the clamp seal off that pierce spot....you'd think they could use duct tape to hang em huh? I use it for most anything else...