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Discussion Starter · #1 ·
Basically had to pour about a quart (1/2 coolant to 1/2 distilled water) of fluid back into my radiator this past weekend. Since then it's gone down about 1/4 quart (1/2 inch) in 3-4 days and I can't for the life of me see where the hell it's leaking.

Anyone have any bright ideas on how to trace where it might be occurring? Isn't there some kind of UV florescent dye I can use to track it down?

If so, where can I pick a cheap kit with the UV florescent dye and a black light to find out where it might be happening? This leak sure doesn't seem strong enough to stay wet to see anywhere. Truthfully, I'm not even sure I'll find anything if it dries up too quickly.

Thanks.
 

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Are you parking it on pavement? I had a super slow drip on a truck that I always parked on gravel and never noticed it but when I parked it on pavement overnight I found the super slow leak. It was a hose clamp and took forever to find.
 

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Discussion Starter · #3 ·
No, I'm parked on pavement and I still see no drips with or without the skid plate on it.

I don't see any cheap kits online so I was thinking of just buying what appears to be a strong LED flashlight and amber shades from Walmart that's advertised to see the dye and a bottle of dye from an auto parts store. Not sure if that's the best way to go.
 

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I had a slow drip for years. Turned out to be the lower radiator hose. What cued me in was the skid plate rusted through on that side just below the hose. Never any evidence of moisture. Never a puddle. Always the faint scent of radiator fluid. I still suspect my heater core but have not gotten around to that.
 

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Discussion Starter · #7 ·
how's the trans fluid looking?
Looks fine (clean). Right to the top of the full line when warmed up to temperature.

replace the cheapest thing(s) first, like the hoses.
I'm guessing the dye thing doesn't really work well for minor leaks or am I mistaken? Is it normal to replace all the hoses after 13 years or just what's needed?

I need to replace the radiator due to age, but I want to make sure it's not something else before I go ahead and drain it before replacing it.
 

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What do you consider slow? When was the last time you checked it? Coolant/water does evaporate and needs to be topped off occasionally. If you haven't checked it in years and just now did because it started to overheat that might be the case and it just needed to be filled up. The extra amount the overflow went down after you filled it up was because it was REALLY low and there was air in the system. When the system cools off the system will suck in coolant to replace it and it can take a couple of cooling cycles to get all the air out.

Yes, hoses are one of those normal maintenance things especially the upper and lower radiator hoses. Around the 4-5 year mark you should probably check them and then keep an eye on them occasionally. Any time they are getting out of shape, bulging or feel spongy they should be replaced.

If your trans fluid is clean have you ever noticed more water vapor coming out of the tailpipe than normal or any stumbling from the engine to indicate a leaking head gasket?
 

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Discussion Starter · #9 ·
What do you consider slow? When was the last time you checked it? Coolant/water does evaporate and needs to be topped off occasionally. If you haven't checked it in years and just now did because it started to overheat that might be the case and it just needed to be filled up. The extra amount the overflow went down after you filled it up was because it was REALLY low and there was air in the system. When the system cools off the system will suck in coolant to replace it and it can take a couple of cooling cycles to get all the air out.

Yes, hoses are one of those normal maintenance things especially the upper and lower radiator hoses. Around the 4-5 year mark you should probably check them and then keep an eye on them occasionally. Any time they are getting out of shape, bulging or feel spongy they should be replaced.

If your trans fluid is clean have you ever noticed more water vapor coming out of the tailpipe than normal or any stumbling from the engine to indicate a leaking head gasket?
Slow is when the level drops and I notice no leakage as a result.

I drain the fluid twice and refill every couple years with a 100-200 miles on the odometer before the 2nd fill since I can't drain the block. The radiator has never overheated since I do check it.

When I check it, it's usually 2-3 times a year and I typically have some overflow into the secondary reservoir when the radiator gets hot. When the reservoir drained completely, it gave me cause for concern since it was below the 'L' mark.

No excessive water vapor from the tailpipe or engine stumbling other than when the coil packs weren't firing, but that was a different issue.
 

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Any chance you did a little off roading? I have noticed that a few times I have been off road and bounced a little coolant out of the overflow reservoir. Just a thought. My 87 4x4 weeps a little from a few hose clamp areas. It isn't that much but I sometimes see a drip at the edge of the lower radiator where the large hose is clamped on.
 

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Discussion Starter · #11 ·
Any chance you did a little off roading? I have noticed that a few times I have been off road and bounced a little coolant out of the overflow reservoir. Just a thought. My 87 4x4 weeps a little from a few hose clamp areas. It isn't that much but I sometimes see a drip at the edge of the lower radiator where the large hose is clamped on.
No offroading. I've been looking at the radiator fluid level with the cap off daily before I go to work in the morning and I notice it being slightly lower than the day beforehand.

About 15 miles of travel daily through the week.
 

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I had a "slow" radiator leak once, and the leak got worse and worse. Our radiators (at least on my 2000 Tundra) is a combination of metal and plastic. The plastic, over time, will come away from the metal.

Right in front of my intake was where my leak appeared, and it was subtle. I didn't notice it until one day I was severely low on coolant (while driving on the highway).

At that point, I had over 200,000 miles on my original radiator. It was time to change it. I bought one on eBay for about $85, and it works like a charm now.

______

The argument goes that we ought to change the radiator hoses when we replace the timing belt, since everything is taken apart and easily accessible.

Rubber does degrade over time, but replacing the radiator hoses frequently is not usually important.
 

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Discussion Starter · #15 ·
http://www.tundrasolutions.com/forums/1gen-tundra/225632-still-running-your-original-radiator-change/

I'm not hijacking a thread but merely wanting to pass on this somewhat related information with our Tundra vehicles equipped with an automatic transmission. It's been around and around but something well worth knowing.
This is exactly what happened to my brother's Tundra at around 135K miles after 10 years of ownership ~ the dreaded "Strawberry Milkshake." :eek:
Exactly the reason I plan on changing the radiator, but I'm not quite sure if a slow leak is a pre-cursor to that happening. I wanted to see if there's anything else I need to fix so I don't have to drain the fluid and possibly replace it again if the leak is still present after changing out the radiator requiring me to put the dye in to find out the source of the leak.
 

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I had a VERY small coolant leak a while ago. So little that over a period of about a month I would notice a gradual change of the amount of coolant in the overflow bottle. I could see what looked to be some dried coolant around the base of the radiator cap. I took the cap off and it looked to have been leaking around the seal, so I just cleaned the seal off and put it back on. This slowed down the leak so I just went and got a new cap for $13 and that fixed the problem. I never saw the leak because it would only leak when I was driving it and it was up to temp and because it was so small it was only a little bit of steam coming out that you could never see.

Might not be your issue, but that just another cheap part you can try replacing
 

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Discussion Starter · #17 ·
I'm beginning to think this is the beginning of cross contamination. Just drove it for 5-6 miles on back roads to get the transmission up to temp and it's now 1/4" over the full line. Coolant has also dropped another 1/2" just after the drive with no external leaks to see.

Should I just not drive it to further cross contamination until the new radiator arrives the middle of next week? It's a 10 mile trip to/from work but I don't think I should chance it. I'm guessing from the radiator level it's probably no more than a quart cross-contaminated, if it even really is to begin.

Not sure if I need really to flush out the transmission in addition to the coolant. Maybe just keep a close eye on the level and color.

Also when changing out the radiator how much tranny fluid would I expect to spill from the auxiliary transmission cooler once the lines are disconnected?
 

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I'm beginning to think this is the beginning of cross contamination. Just drove it for 5-6 miles on back roads to get the transmission up to temp and it's now 1/4" over the full line. Coolant has also dropped another 1/2" just after the drive with no external leaks to see.
If there were coolant in your tranny you'd see it on the dipstick. The 1/4" rise is just thermal expansion of the tranny fluid.

Should I just not drive it to further cross contamination until the new radiator arrives the middle of next week? It's a 10 mile trip to/from work but I don't think I should chance it. I'm guessing from the radiator level it's probably no more than a quart cross-contaminated, if it even really is to begin.
If there's no visible coolant or strawberry milkshake on the tranny dipstick I wouldn't worry about it. Any coolant in the tranny could not hide, it would be thoroughly mixed with the tranny fluid.

Also when changing out the radiator how much tranny fluid would I expect to spill from the auxiliary transmission cooler once the lines are disconnected?
Very little. A few ounces.

I'm betting this is what you'll find:

Metal
 

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Discussion Starter · #19 ·
If there's no visible coolant or strawberry milkshake on the tranny dipstick I wouldn't worry about it. Any coolant in the tranny could not hide, it would be thoroughly mixed with the tranny fluid.
Yeah, I was reading up on it and it sounds like even a small amount of water (not sure how much) has a very large effect upon the transmission fluid. Not sure if I should go the extra step of sending a sample to BlackStone Labs for water analysis of the tranny fluid for $25 just for peace of mind after I change out the radiator. I'm beginning to think the UV dye approach isn't a very good one if there's cross contamination since the dyes are either made for oil, coolant or AC refrigerant.

I may try the UV dye approach if the radiator replacement doesn't work in arresting the coolant leak.
 

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If you have clear red tranny fluid I wouldn't be concerned. Any coolant in the tranny will form an emulsion with the tranny fluid (milkshake) and be totally obvious. However, a $25 fluid analysis is cheap insurance.

How old is your water pump? A slow coolant leak will most likely be either a leak at the water pump gasket or at the bearing (weep hole), a seeping radiator or a leak at one of the two water pump o-rings.
 
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