My 87 Pickup 22R auto 2 whl drive (355,000 miles) has a radiator issue that I don't understand. I wouldn't call it a problem as the truck doesn't overheat. There's no apparent coolant leak while running or after shutdown. The next morning there's a 4' to 6' puddle of coolant under the right side (passenger side) of the radiator. Why would coolant leak out of a cold radiator over time when it doesn't leak out of a hot radiator under pressure?

 

Maybe if you knew where the coolant was really coming from, an answer could be determined.

First thing is to find the actual point of leakage.

 

Follow the coolant upward. Find where it is dripping under the truck, even if you have to look closely for dried coolant, and follow it up from there.

 

Thanks 91bluerunner. I hadn't thought to look for dried coolant. The radiator is an aluminum replacement unit with a lifetime warranty from Napa. If I have to replace it no big deal.

 

No worries, happy to help! Sometimes drips are very, very sneaky. Let us know what you find.

 

crack in the overflow bottle?

 

That's the first thing I checked. I couldn't find a leak but maybe I missed it. The overflow bottle is a prime suspect because the problem happens over time and isn't pressure related.

 

could it be that the cooling system itself is functioning fine, but after the car is off and water flow/airflow ceases, the water temp climbs and the radiator cap is simply not holding quiet enough pressure, which is then allowing a small amount to overflow into the overflow bottle and in-turn, filling the bottle to the point that IT ALSO over flows just a small amount onto the ground...and then as it all cools back down the excess cooland in the overflow bottle is sucked back into the radiator?

there are also things like hot and cold leaks which should be considered

 

The leakage appears under the car overnight, not within an hour as it would if the bottle was overflowing after shut-down. I don't know what a cold leak is or how it would occur. ?????

 

I had a new radiator that was leaking and it was leaking around the drain plug fitting. There was a hairline crack because of a bad soldering job. But mine isn't an aluminum radiator. If your are parked on level ground, You could put something under your truck to catch the leaking coolant. Doing this can help you narrow down where the leak is coming from. I use a razor knife to cut a plastic one gallon jug in half to make a bowl. Most likely the leak is from the drain plug or your radiator. Usually the drain plug has a seal like a rubber o-ring.

 

Found the leak and watched it drip. Had to take the fan shroud off to find it. It's near the bottom of the radiator driver's side. Found discoloration there. It only leaks when the engine is cold, which makes no sense to me. What is a "Radiator cold leak" and how does it occur. I tried "K-Seal" once before and it seemed to reduce the leak, but didn't stop it. Should I try "K-Seal" again? Or is there something else which might work better?

 

Stop leak products cause more problems than they correct.

They plug heater cores and further restrict carefully engineered passages thru the headgaskets, often causing localised overheating in the head, and generally damaging
cooling system performance in general.

The only proper repair is to take the radiator to the shop for boiling/rodding out and solder repair.

If the radiator cannot be saved, new replacement is the answer.

 

"K Seal" was recommended to me by Yodaman, a top Toyota specialist in the Santa Rosa area. My radiator is an aluminum replacement unit from Napa. I would have preferred an old school brass radiator but Napa told me the aluminum unit had a lifetime warranty. I don't know if boiling/rodding/solder works on an aluminum radiator. What does? It seems a shame to replace the radiator over a small leak that doesn't affect the running of the truck and only leaves a small puddle in the morning. I'm going to talk to Napa this week and see what they have to say.

 

If I had a lifetime warrantee radiator, I never woulda even considered for a second, fouling my cooling system with stop-leak.

They wouldda had that thing back, toot sweet!!

I don't know what to say about 'specialists and experts' who recomend cooling system stop-leak products.

As for me, I'll stay far away from 'em. Stop-leaks and specialists alike.

Soldered brass and copper radiators are still easy to find for Toyota trucks, I would'nt buy anything else for a machine I intended to keep.

Aluminum radiators work well, til they don't. Repair is seldom satisfactory.

 

that's not very specific, are you looking at a drip spot and not the real leak? maybe get the radiator pressure tested.

when the engine cools down, it should be pulling fluid back from the overflow tank into the radiator... how soon did the leak appear after shutting off the engine?

 

If it were me, I would pull the radiator and take it to a shop and they can pressure test it, fix leaks and flush it out with a power flush that knocks all kinds of crud out of the radiator and in some cases I have seen the temperture gauge drop 1/4 just because it is cooling that much better.

I still prefer the old brass radiator, even if I have to get one from the boneyard and have it repaired. I am slow to change to the newer things and the old radiators have been working great for years.

I would get the sealant stuff out and fix it correctly if it were me.

 

You can easily rent a pressure tester from Auto Zone (free if you bring it back within a week or so). That will allow you to pressurize the cooling system with the engine off and cold, so you can safely really look into where the leak is coming from. I recommend that as your next step before you do anything else. Pump it up to 15-18 psi and I'll bet the leak will be obvious.

As far as why it leaks when cold, metals contract when they cool off, potentially allowing a small crack to open up. When things are hot the metal expands and seals it up. A plausible theory, anyway.

 

I took advantage of my lifetime warranty from Napa and got a free replacement radiator. One minor problem that concerns me: The radiator I've used in my in my 2 wheel drive truck for five years is part number 2041, specified for 4 wheel drive trucks. The two wheel drive radiator is part number 945. The replacement I have from Napa is a 2041, which matches what I've been using. Is anyone up to speed on Toyota part numbers and can tell me the difference between a 945 and 2041? And does it matter?

 

I don't know the difference between a 945 and a 2041. Wait,no, really, I do. The answer is....1096... ba-da-bing......

These numbers are numbers generated by NAPA and their suppliers, only they are in a position to tell you what differences there are, if any.

Likely your Napa aluminum radiator is Chinese slave labor goods. What does your packageing/literature say about it and where it came from???

Toyota uses a completely different parts number system that uses ten digits.

I would be suprised if Toyota would sell you an aluminum radiator for your year truck.

 

Installed Napa radiator #2041 today. Job was easy with no complications and no leaks afterwards. Total cost of repair under $20 for coolant and a few shop supplies.