Help with small leak on New hose after new radiator install.

[WilliamM2]

After replacing the radiator and hoses 2 weeeks ago, I appear to have a leak on the lower hose, on the upper connection to the thermostat housing. At least it's easy to get to. It's been two weeks since I did the repair, but I don't drive much, so it only went for a couple drives before a trip yesterday. It's a 2009 Camry, see other thread here:

Opinions on new Radiator I recieved.

I have a 2009 Camry with a leaking radiator. So I ordered a Denso replacement from Rock Auto. The radiator arrived with a slight bend/twist to one of the end rails. The radiator holds pressure. Just wondering if this kind of damage could cause an issue in the future. Dent on box that lines up...

forums.anandtech.com

The day I replaced the rad, it ran in the driveway for about an hour. No leaks. I have driven the car three times since. And I have been checking for leaks every couple of days, because...I'm paranoid, and because I wasn't sure if I got all the air out, so also checking the resevoir levels.

1st drive, 14 miles each way to the dentist a couple days after I replaced it, stop and go traffic all the way. No leaks, checked it when I left the dentist, and when I got home.

2nd drive, went to the grocery store, 15 miles round trip. No leaks.

3rd drive yesterday. I went to visit relatives 75 miles away. When I got there, I checked it right away, still no leaks. I drove about 8 miles to another relatives house, and checked again (told you I was paranoid). Several drips from the hose where it connects to the thermostat housing. I drove 70 miles back home, and stopped to fill up the gas tank about 5 miles from home. No leaks/drips visible at the gas station, but when I parked at home 5 miles later, there were a few more drips.

After I wipe it up, it doesn't appear to leak while just parked. It's been sitting overnight, still dry. It's been about 45f or so each time I've driven it.

So what is the solution? They are brand new gates hoses, original Toyota spiring clamps in good shape. Should I try any kind of sealant? Would it help to just re-adjust the clamp to a new position?

Other than this, it seems to be cooling perfectly. Temp gauge reads exactly where it did before. I was concerned that the thermostat wasn't opening, because the lower hose stays fairly cool, about 85f to 90f. Upper hose is 175f at engine end, 160f at the radiator end. So I took my wife's car (2009 Camry just like mine) and had the same results, lower hose stayed cool, temp readings were within 5f of mine, both upper and lower. But I only went about 20 miles. I'll assume that's normal for a 45f day?

Any suggestions would be great. I hope I don't need to dump all that fre$h coolant. @crashtech , since you do this for a living.
Thanks.

Here's pics, doubt it helps:

 

[Jimminy]

I would try to get rid of the spring clamp and use a regular worm gear clamp, if it is possible.Re-positioning that original clamp might help. Sealer on the inside of the hose might work too, but I just dont trust those spring clamps. I leave them alone it they are working though. I hate plumbing of any kind, but it's a necessary evil

Since it's only leaking a few drops, it may eventually seal, just from heat and temp cycling.

But if you do decide to replace the clamp, be sure to look at the inside of the hose, just to be sure it doesn't have some defect that's causing the leak.

Oh yeah, DON'T dump that expensive antifreeze. Catch it in a clean pan (like one of those cheap plastic oil drain pans). That new antifreeze can be re-used. Pan doesn't have to be perfectly clean, so you can just wipe down whatever drain pan you have, just be sure it's big enough to hold whatever the coolant capacity is. Or use two pans and switch them out quickly.

 

[mindless1]

It's a plastic thermostat housing, yes? If so then I would carefully inspect it for cracks, and also take the hose off, feel the inside for irregularities, make 110% sure that the housing nipple is clean/smooth, and replace the original spring clamps with new spring clamps. The cheaper option is take the spring clamp off, and compress it into a little tighter radius, then put it back on.

Since (if) it is a plastic housing, you could get away with using a worm gear clamp (the plastic does not have same coefficient of expansion that a metal nipple would, so lessens the impact of lack of expansion that a spring clip provides) and I might consider doing so if they are significantly less expensive, but otherwise would just get a new spring clamp.

A sealant might also solve this but shouldn't be needed and could end up being a pain to deal with if/when the hose needs taken off at a later date.

Why would you need to dump all that coolant if only disconnecting something (presumably?) that high up in the cooling system? As Jimminy mentioned, you can just catch in a container what leaks out, and if there's grime in it, run it through an old t-shirt/rag over a big funnel to filter it "good enough".

 

[WilliamM2]

It's a plastic thermostat housing, yes? If so then I would carefully inspect it for cracks, and also take the hose off, feel the inside for irregularities, make 110% sure that the housing nipple is clean/smooth, and replace the original spring clamps with new spring clamps. The cheaper option is take the spring clamp off, and compress it into a little tighter radius, then put it back on.

Since (if) it is a plastic housing, you could get away with using a worm gear clamp (the plastic does not have same coefficient of expansion that a metal nipple would, so lessens the impact of lack of expansion that a spring clip provides) and I might consider doing so if they are significantly less expensive, but otherwise would just get a new spring clamp.

A sealant might also solve this but shouldn't be needed and could end up being a pain to deal with if/when the hose needs taken off at a later date.

Why would you need to dump all that coolant if only disconnecting something (presumably?) that high up in the cooling system? As Jimminy mentioned, you can just catch in a container what leaks out, and if there's grime in it, run it through an old t-shirt/rag over a big funnel to filter it "good enough".

This connection is about 4 or 5" below the top of the radiator, so it will pour out coolant. I could drain out a couple of quarts first. I did inspect everything, and clean all connections when I first did the job. The housing and nipple was smooth and clean, and didn't leak before, so I'm pretty certain it's not cracked. Hose was nice and smoth inside. Oddly the other (upper) hose wasn't quite as smooth, but is holding fine. Both are Gates.

As far as worm clamps, I never use them on plastic. And it gets really cold here, which often causes them to leak. Plastic expands and contracts, more than metal, not less.

I just re-positioned the clamp a couple mm farther from the barb/nipple. I looked at the old hose, and it was a little farther from the barb than I had it. Also rotated the hose slightly left, and rotated the clamp to the right. Hoping it just wasn't quite right. I've never had issues re-using spring clamps before, and this was the first time it was ever removed.

I let it idle in the driveway for 35 minutes, so far so good. But it took two weeks to drip the first time, so who knows? If it drips again, I'll get a new spring clamp, but Toyota wants $25 for them! Old hose in first pic.

 

[Torn Mind]

Could be that the aftermarket fellas(hose, rad, or both) didn't quite get the measurements down right. (I just had an experience with a bad phone screen replacement where the LCD had no touch and the screw holes didn't fully line up.)

I'm not sure how much it matters in actually, but some say no to worm clamps for the heated liquid system due to expansion cooling. .

I used the old clamps for my mom's Corolla Matrix and the original hoses....at 100k.

 

[WilliamM2]

Could be that the aftermarket fellas(hose, rad, or both) didn't quite get the measurements down right. (I just had an experience with a bad phone screen replacement where the LCD had no touch and the screw holes didn't fully line up.)

I'm not sure how much it matters in actually, but some say no to worm clamps for the heated liquid system due to expansion cooling. .

I used the old clamps for my mom's Corolla Matrix and the original hoses....at 100k.

It's not leaking at the radiator. The hoses fit good and snug. I was surprised it took a little effort get the new one to rotate a little bit, since it was only on for two weeks.

I probably could have re-used the OEM hoses, but I didn't want to risk a leak with 14+ year old hoses. Go figure.

 

[crashtech]

This thread reminds me of why we have a vacuum filler and a pressure tester for coolant system work. It seems simple, and it is in principle, but in application, numerous things do go wrong on a regular basis. Could be something as simple as a chunk of corrosion or precipitated coolant byproducts on the bottom of the hose where it was out of view during re-assembly. It has happened to every mechanic, or will. If it was mine to do, (since the hose is new) we'd drain the system, clean the connection, and refill. It's not the clamp, though a new one would not hurt.

 

[WilliamM2]

This thread reminds me of why we have a vacuum filler and a pressure tester for coolant system work. It seems simple, and it is in principle, but in application, numerous things do go wrong on a regular basis. Could be something as simple as a chunk of corrosion or precipitated coolant byproducts on the bottom of the hose where it was out of view during re-assembly. It has happened to every mechanic, or will. If it was mine to do, (since the hose is new) we'd drain the system, clean the connection, and refill. It's not the clamp, though a new one would not hurt.

When I moved the clamp back to rotate the hose a little, I did pull the hose off enough that some coolant came out. I was also trying to see if the housing had any damage I missed, and was smooth. Maybe if it was a small particle, it's rinsed away now.

I wish I had a pressure tester, but not sure if it would have helped in this case, as it did hold pressure for over 125 miles of driving. I was checking it after each drive by running a white paper towel around each of the connections, including the trans cooler hoses. Pink coolant is easy to see. It might help to have one now to see if I got it.

 

[WilliamM2]

This thread reminds me of why we have a vacuum filler and a pressure tester for coolant system work. It seems simple, and it is in principle, but in application, numerous things do go wrong on a regular basis. Could be something as simple as a chunk of corrosion or precipitated coolant byproducts on the bottom of the hose where it was out of view during re-assembly. It has happened to every mechanic, or will. If it was mine to do, (since the hose is new) we'd drain the system, clean the connection, and refill. It's not the clamp, though a new one would not hurt.

Could a bad rad cap cause this? I noticed yesterday, and Sunday, that the level did not rise in the overflow tank when up to temp. I put it down to cold weather (45f or less). I did put a new Motorad cap on too.

I checked my wife's car when she got home from work last night, a whopping 8 mile drive in 25f weather, and hers had risen above full by 3/8" or so. It's back down to full this morning of course.

I have them both running in the driveway right now with the old cap back on my car...I'll see if it rises now.

 

[Motostu]

The cap could potentially cause issues if it doesn't keep the pressure in the system from building past a certain level. If it's sticking for some reason, the pressure can build up too high and you could get some weeping.

 

[WilliamM2]

With the old cap on, I idled each car for half an hour, her tank level rose a 1/4", mine barely at all, So then I drove each car for about a 7 mile loop in slushy crap, hers rose up about 3/4" or better, mine came up about half as much. My level didn't move at all yesterday or Sunday that I could tell. I was actually looking for the level to drop if I hadn't got all the air out, so I never thought about it until last night.
And it didn't drip this time, but it's only done that twice on Sunday's trip. It's 28f today.

I'm sure all the air is out after 200 miles? I did bleed it when I installed as well. I'll check levels again when the roads clear, maybe with the new cap. We are having weird weather here. We are usually buried in snow by now. But it's snowed twice so far, and then it melts. Will be 50 again by the weekend.

They are sending a replacement, no return needed. Will any of the auto parts stores test caps? I'd like to know if it's really bad. My test isn't too conclusive, at least to me.

 

[crashtech]

It's prudent to replace the cap when doing a major coolant service, but it would be very rare for a bad cap to result in over-pressurization of the system. The only cap failures I have witnessed is either a failure to hold pressure, and/or a failure to hold vacuum, which is needed to draw coolant back into the system from the overflow bottle when the system cools.

 

[WilliamM2]

It's prudent to replace the cap when doing a major coolant service, but it would be very rare for a bad cap to result in over-pressurization of the system. The only cap failures I have witnessed is either a failure to hold pressure, and/or a failure to hold vacuum, which is needed to draw coolant back into the system from the overflow bottle when the system cools.

Thanks,
I agree, but I can't explain why my overflow tank was not rising when hot. It always had in the past. And it did today with the old cap.

So if it releases pressure, is it at 16psi like it should be?

 

[crashtech]

There's a spec that varies between vehicles, but it's generally between 14-18psi. I don't know what yours is supposed to be offhand.

 

[WilliamM2]

There's a spec that varies between vehicles, but it's generally between 14-18psi. I don't know what yours is supposed to be offhand.

Mine is 16psi. I'll just have to wait and see if the one they send as a replacement works like the OEM.

Intermitent leaks are annoying, No real way to know if it's fixed or not, at least for a while.

 

[Torn Mind]

It's not leaking at the radiator. The hoses fit good and snug. I was surprised it took a little effort get the new one to rotate a little bit, since it was only on for two weeks.

I probably could have re-used the OEM hoses, but I didn't want to risk a leak with 14+ year old hoses. Go figure.

I had the wrong location, but the gist is still the same. The new hose is different enough somehow to not seal.

Seems like all the issues boil down to aftermarket tolerances being not the same as OEM.

OEM Toyota is also pretty tough stuff.

Hoses, the liquid ones can, suprisingly, last in lifespan. The vaccum hoses are a different story, especically the valve cover gasket was not timely replaced and the oil is able to damage them.

 

[WilliamM2]

Seems like all the issues boil down to aftermarket tolerances being not the same as OEM.

Doesn't seem that way to me at all. They are rubber hoses, and tight.

 

[Paperdoc]

Three thoughts.
1. You have some worries about whether or not you were able to bleed out all the air. With the driving you have done, any still-trapped air would have migrated to the top of the rad by now. So when the engine and rad are COLD (do NOT try this hot!) remove the rad cap and check. IF it is not completely full up to the rad cap neck, top it up with spare coolant mix. Maybe WAIT and do this AFTER my next thought.

2. You also say that the suspect connection is about 5" below the rad top. So if you could drain enough coolant into a pan to drop the rad level to nearly empty, there would be no coolant to leak out when you disconnect at that point. You have not told us HOW you drained it to make the original repair. But the RAD itself should have a drain valve at the bottom. Often it's kind of tucked away but if necessary you can stick a short hose on the end of the valve to direct the drainage into your pan. Open the valve and remove the rad cap to drain the system (mostly). When it stops draining, close the valve and do your adjustments. CLOSE the drain valve and re-install the drained coolant until the rad is almost full, then start up with the rad cap still OFF. Watch the coolant level. It will drop when the engine heats up enough to open the thermostat. Slowly add more of the recovered coolant until it is all in. If necessary, top it up while still open and not under pressure. THEN put the rad cap back on. Check the drain valve underneath to be sure it is not leaking. When you shut down and the system cools off it will suck some coolant back from the expansion tank. If that level is too low, top it up.

3. It is possible that the leak is very small, so that when you drive a long distance it all evaporates from the hot pipe and hose and you don't notice. But on a short drive if you start out cool it may not evaporate before you look.

 

[WilliamM2]

Three thoughts.
1. You have some worries about whether or not you were able to bleed out all the air. With the driving you have done, any still-trapped air would have migrated to the top of the rad by now. So when the engine and rad are COLD (do NOT try this hot!) remove the rad cap and check. IF it is not completely full up to the rad cap neck, top it up with spare coolant mix. Maybe WAIT and do this AFTER my next thought.

2. You also say that the suspect connection is about 5" below the rad top. So if you could drain enough coolant into a pan to drop the rad level to nearly empty, there would be no coolant to leak out when you disconnect at that point. You have not told us HOW you drained it to make the original repair. But the RAD itself should have a drain valve at the bottom. Often it's kind of tucked away but if necessary you can stick a short hose on the end of the valve to direct the drainage into your pan. Open the valve and remove the rad cap to drain the system (mostly). When it stops draining, close the valve and do your adjustments. CLOSE the drain valve and re-install the drained coolant until the rad is almost full, then start up with the rad cap still OFF. Watch the coolant level. It will drop when the engine heats up enough to open the thermostat. Slowly add more of the recovered coolant until it is all in. If necessary, top it up while still open and not under pressure. THEN put the rad cap back on. Check the drain valve underneath to be sure it is not leaking. When you shut down and the system cools off it will suck some coolant back from the expansion tank. If that level is too low, top it up.

3. It is possible that the leak is very small, so that when you drive a long distance it all evaporates from the hot pipe and hose and you don't notice. But on a short drive if you start out cool it may not evaporate before you look.

Thanks, but...

1. Radiator is fully topped up, I changed the cap today to the old one. I think you are correct, all the air is out.

2. I didn't say how I drained it, but did state I changed the radiator and all hoses and cap. So it was drained. I have changed coolant before. Used a no spill funnel to bleed the air, and let it idle in the driveway for about an hour after install.

3. The first time I noticed it drip was immediately after parking and shutting the engine off, after driving 8 miles. I get out of the car and open the hood. It's the lower hose, it was not hot, in fact still cold at the lower end. Second time was later the same day after driving 75 miles home, and it was not dried up. Dried Toyota pink coolant is easy to see. It also was not leaking while I gassed up the car (still running). It seems like it leaked right when I shut it off at home 5 miles later. It's all in the first post.

It was a tiny leak, just a few drops. And it has not leaked while just sitiing in the driveway idling, while I stand and watch. Or dripped at all while being parked for up to a week.

 

[jmagg]

Water pumps leak after the car is turned off. It starts slow and intermittent and get progressively worse. I know you said you see the leak at the hose but water is tricky. Just something to look at.

 

[WilliamM2]

Water pumps leak after the car is turned off. It starts slow and intermittent and get progressively worse. I know you said you see the leak at the hose but water is tricky. Just something to look at.

I checked that. The connection is above and almost a foot to the right of the water pump, and completly blocked by the engine and components.

It was replaced under warranty from a tsb. When they leak it's easy to see. It leaves bright pink dryed coolant on the underside of the hood, from the belt slinging it. Wife's did it too, supposed to be a new revised part.

 

[crashtech]

Since there isn't a pressure tester available, the next best thing is to put a jug of coolant in the car with you and go on a drive that will get the car hot enough to really pressurize the system, like a 5-10 mile jaunt on the freeway. Pull off at a gas station and examine the pressurized system for leaks.

 

[WilliamM2]

Since there isn't a pressure tester available, the next best thing is to put a jug of coolant in the car with you and go on a drive that will get the car hot enough to really pressurize the system, like a 5-10 mile jaunt on the freeway. Pull off at a gas station and examine the pressurized system for leaks.

I've done that, not the freeway, since it's 30 miles from here. I drove it again 10 miles, plus left it idling first for 10 minutes before I left, so two drives now, no drips.

I'll just have to keep an eye on it.

 

[Zorba]

Nvm, don't think I fully read the OP and hadn't read the thread.

 

[crashtech]

I've done that, not the freeway, since it's 30 miles from here. I drove it again 10 miles, plus left it idling first for 10 minutes before I left, so two drives now, no drips.

I'll just have to keep an eye on it.

As long as the upper hose is what my shop teacher used to call "hot and hard" after the drive, you have opened the thermostat and pressurized the system, and at that point if no leaks are evident, there is a good chance that everything is okay.