1992 Camry overheating; recently replaced radiator lost coolant, but no leaks seen

[LineInTheWater]

So, we have a car that is very rarely driven, and usually very few miles at a time. A few months ago, I replaced the radiator because it had several hairline cracks that were seeping antifreeze.

Yesterday, my GF was driving the car for maybe the sixth time since I fixed it. She drove 5 miles without any issues, parked for a few hours, and then started to drive back. Halfway back the check engine light came on and the oil temp gauge was pinned in the red. She continued to drive the remaining 2 miles back to the house (). By the time she got back, there was a small amount of white smoke coming from the engine. She didn't open the hood to inspect.

I went out and looked at the car today, and there was no obvious leak around the oil or coolant hoses on the radiator. Everything looks good. However, the reservoir was empty. And, when I popped the radiator cap, the entire top of the radiator was empty. I have no idea if there is any fluid left in the radiator.

I then looked at the oil dipstick, and it is full (and doesn't look milky).

So, I'm trying to figure out where the leak is located. After some research, I'm starting to think it might be the radiator cap. Is it possible the coolant evaporated through a poorly sealed cap? I didn't replace the cap when I replaced the filter - in fact, I think it is the original cap that came with the car. I'm no expert, but I think it feels more loose than it should.

I just wanted to get some feedback from this forum. Am I on the right track here? Also, do you think damage was done to the engine, or the water pump, by driving a short distance in this state?

Thanks in advance.

[BMR]

It's impossible to be certain if there was any damage done. You meant to say the coolant temperature gauge was pegged, right? I'd top off the cooling system, start it up, and let it idle until warmed up. Look for coolant leaks. Could be a lot of things; water pump seal, hose burst, radiator cap, head gasket, to name some. Was the white smoke coming out the tailpipe?... or just rising up in the engine bay?

Which engine you got?... V6 or 4 cylinder?

[LineInTheWater]

Originally Posted by BMR

It's impossible to be certain if there was any damage done. You meant to say the coolant temperature gauge was pegged, right? I'd top off the cooling system, start it up, and let it idle until warmed up. Look for coolant leaks. Could be a lot of things; water pump seal, hose burst, radiator cap, head gasket, to name some. Was the white smoke coming out the tailpipe?... or just rising up in the engine bay?

Which engine you got?... V6 or 4 cylinder?

Yes coolant sensor. Sorry.

No white smoke coming from the tailpipe - just a small amount coming from the engine bay.

4 cylinder.

[coffee-3000]

I saw the following comment in the service manual: "The radiator cap is a pressure–type cap which seals the engine coolant circuit and the resulting pressurization of the engine as the coolant expands. The pressurization prevents the coolant from boiling even when the coolant temperature exceeds 100
C (212
F)."

So if your radiator cap isn't sealing the pressure, your coolant might be boiling which might be causing the guage to show a higher than normal temperture.

Another member of this forum (i.e. dc_98_cam) wrote the following earlier this week in regards to a similar issue:
"If the radiator cap did not seal, the atmospheric pressure boiling water ... i.e. steam ... would have to escape from the radiator. The coolant reservoir bottle would be empty ... and the level of coolant in the radiator would get lower ... over some period of time. "
A radiator pressure tester can check for pressure leaks in the coolant system, and often there is an adapter to actually test the effectiveness of radiator caps ... "

[LineInTheWater]

I filled the radiator and coolant reservoir. It took over 10 cups of coolant to top it off - I think it was bone dry. There was some liquid below the reservoir which appeared to be water, but I'm not sure. I wiped it all up so I can see if any new liquid appears. I'm leaving the car for a few hours before starting, in case there is a big leak somewhere. I will double-check coolant level before starting, and then will start and look closely for leaks (keeping an eye on the temp sensor).

[LineInTheWater]

I went out to start the car. Shortly after the I got it started, a small pool of liquid began developing under the radiator - near the right oil line. It was clearly antifreeze. I checked all the coolant hoses, and no sign of leaks. Then I realized a portion of the radiator top (just below the black coolant tube that spans the top of the radiator) was oozing and pooling antifreeze.

Is there anything I might have done in the install of the new radiator that may have resulted in the radiator losing it's structural integrity? Or, do you think this is simply a bad radiator? Or did the radiator crack because something else broke, and caused the pressure to get too high in the radiator? Water pump? I'm kinda at a loss at this point. I thought I took my time and very carefully installed that thing properly.

[WaxonWaxStillOn]

a defective weld?

[BMR]

Could be the radiator cap isn't venting at the pressure it should, overpressurizing the radiator. When you replaced the radiator, did you also replace the cap?

Or it could be you just got a bad radiator. Can you tell more about where it's leaking? Is the upper plastic cap cracked?... or is the joint between the cap and the core leaking. Doesn't really matter, though. You should be able to get a replacement for free under warranty?... even the cheapest rads give you *some* kind of warranty. I'd say replace it again (if you can get a free one), and also replace the radiator cap. Go with genuine Toyota on that. Well worth the extra few bucks it costs. A lot of the aftermarket caps are complete crap.

[LineInTheWater]

Originally Posted by BMR

Could be the radiator cap isn't venting at the pressure it should, overpressurizing the radiator. When you replaced the radiator, did you also replace the cap?

Or it could be you just got a bad radiator. Can you tell more about where it's leaking? Is the upper plastic cap cracked?... or is the joint between the cap and the core leaking. Doesn't really matter, though. You should be able to get a replacement for free under warranty?... even the cheapest rads give you *some* kind of warranty. I'd say replace it again (if you can get a free one), and also replace the radiator cap. Go with genuine Toyota on that. Well worth the extra few bucks it costs. A lot of the aftermarket caps are complete crap.

As mentioned, I did not replace the cap when I replaced the radiator.

The radiator is leaking where the core meets and wraps around (attaches) to the black plastic - for lack of a better description. Maybe that is what you are calling the "joint". I don't see any cracks in the plastic.

Yes, it was a cheap ebay aftermarket radiator. I can't remember the warranty period. Need to look it up.

[LineInTheWater]

The radiator has a lifetime warranty.

I'm hesitant about calling about the warranty before I ensure something else didn't cause the radiator to fail. Is there anything else that could have caused this? Maybe I should take pics of where I think it is breached?

[LineInTheWater]

I ran down and did another test. I wiped up any residual fluid from yesterday, and started the car (cold). Initially, the fluid started to seep out the right edge of the top of the radiator - at the seam between the metal and plastic. I continued to wipe it up with a paper tower. I also saw a small drip of coolant on the belly pan, near the oil hose, but I can only assume it was somehow traveling from the top (I couldn't find a path). Eventually, I saw glistening fluid all along the seam on top (between metal and plastic), traveling far to the left of the radiator. I'm assuming this was one leak on the right seeping all along the housing. However, once the car warmed up, the fluid almost disappeared. Two theories on that: either it was evaporated on contact with the hot metal, or some expansion was occurring and closing off the leak.

I left the car on for a good 20-25 minutes, keeping a close eye on the temp sensor. It slowly climbed to normal temp, and stuck there. The radiator hose was hot, so I'm assuming that implies the water pump is working properly? I had my GF keep her foot lightly on the gas pedal for a minute, in order to get the radiator fans to come on ... and they did, quickly going off within a minute of starting. So, I'm assuming this means the car is detecting a small drop in temp, and the radiator is working properly.

Right now, I'm betting it is a bad radiator. But not being an expert or anything, is there anything I've said here that makes you think otherwise?

[BMR]

Originally Posted by LineInTheWater

I ran down and did another test. I wiped up any residual fluid from yesterday, and started the car (cold). Initially, the fluid started to seep out the right edge of the top of the radiator - at the seam between the metal and plastic. I continued to wipe it up with a paper tower. I also saw a small drip of coolant on the belly pan, near the oil hose, but I can only assume it was somehow traveling from the top (I couldn't find a path). Eventually, I saw glistening fluid all along the seam on top (between metal and plastic), traveling far to the left of the radiator. I'm assuming this was one leak on the right seeping all along the housing. However, once the car warmed up, the fluid almost disappeared. Two theories on that: either it was evaporated on contact with the hot metal, or some expansion was occurring and closing off the leak.

Seems plausible to me. The upper cap is crimped to the core with an aluminum strip around the perimeter. Sounds like that didn't get crimped adequately. They might use a sealant in that joint too; I dunno, never torn one apart to look.

I left the car on for a good 20-25 minutes, keeping a close eye on the temp sensor. It slowly climbed to normal temp, and stuck there. The radiator hose was hot, so I'm assuming that implies the water pump is working properly? I had my GF keep her foot lightly on the gas pedal for a minute, in order to get the radiator fans to come on ... and they did, quickly going off within a minute of starting. So, I'm assuming this means the car is detecting a small drop in temp, and the radiator is working properly.

I agree. Pump and fan system is working properly, and coolant is circulating (not blocked somewhere).

Right now, I'm betting it is a bad radiator. But not being an expert or anything, is there anything I've said here that makes you think otherwise?

Nope, sounds like a bad radiator to me. It's possible the cap caused the system to overpressurize, but that's not usually how a cap fails. They usually open too soon, especially so when they get old. But to be safe, I'd replace it.

It remains to be determined if there was any damage done to the engine. The most likely possibility is that the head gasket has blown. There are tests that can verify that. You've mentioned the oil looked normal, not milky, so it probably isn't leaking coolant into the oil. Also, the coolant can be tested for the presence of exhaust gases. So you could get that done before working on it more.

[LineInTheWater]

Originally Posted by BMR

Seems plausible to me. The upper cap is crimped to the core with an aluminum strip around the perimeter. Sounds like that didn't get crimped adequately. They might use a sealant in that joint too; I dunno, never torn one apart to look.

I agree. Pump and fan system is working properly, and coolant is circulating (not blocked somewhere).

Nope, sounds like a bad radiator to me. It's possible the cap caused the system to overpressurize, but that's not usually how a cap fails. They usually open too soon, especially so when they get old. But to be safe, I'd replace it.

It remains to be determined if there was any damage done to the engine. The most likely possibility is that the head gasket has blown. There are tests that can verify that. You've mentioned the oil looked normal, not milky, so it probably isn't leaking coolant into the oil. Also, the coolant can be tested for the presence of exhaust gases. So you could get that done before working on it more.

Thanks for the sanity check!

If the car sounded completely normal at idle, and when the gas peddle was slightly depressed, isn't there a good chance the engine is OK? Or is that just wishful thinking?

[BMR]

I just re-read your first post, and finally noticed you mentioned the check engine light came on (sorry). Is that still on? If yes, read the error code(s) and let us know what they are. Here's how to read them:

1) With the engine off, put a jumper across terminals TE1 and E1 inside the diagnostics port (a paper clip will do). It's on the passenger's side of the engine bay; rectangular black plastic box sticking up in plain sight with "DIAGNOSTICS" on it. There's a label on the underside of the port's cover identifying the terminals.

2) Switch the ignition to ON (don't start the engine), & watch the check engine light flash the error code. The light will flash some number of times, pause, flash some number of times again, then a longer pause, and repeat. Watch and count the flashes carefully, there may be more than one code. If it just flashes at a steady rate with no obvious pauses, that means there are none.

[BMR]

Originally Posted by LineInTheWater

If the car sounded completely normal at idle, and when the gas peddle was slightly depressed, isn't there a good chance the engine is OK? Or is that just wishful thinking?

Unfortunately, that doesn't mean much. I guess it does mean the head gasket isn't grossly blown, and it didn't get hot enough to seize up. The 4 cylinder engine it's got is more tolerant of overheating than the V6 it might've had. So you've got that goin' for ya.