slim_slc

my truck overheated one day a couple weeks ago. I turns out it was due to a coolant leak that I was not aware of (spilt heater hose)...when i say overheated, the guage never did get to the red, but was very close. That day was a huge blizzard and I had to drive home from work, so I had to drive home....but I did stop to make sure there was plenty of coolant frequently. It only got really hot that one first time, before I refilled the coolant. Also on the way home my heater stopped working. So, I drained the radiator, replaced the thermostat with a failsafe aftermarket one that locks open if it fails, so I don't overheat again. I knew my thermo was going bad because I was starting to lose heat in the cab prior to the overheating.

Anyway, this was about two weeks ago. I have been watching diligently for leaks of coolant and not seen any. I have also frequently checked my coolant level. A couple days ago I was driving to work and my heater stopped working again. When I pulled back in my driveway I noticed a puddle of coolant under the truck.

There is no sign of oil in the coolant. Don't have a way to know if there is coolant in the oil...although smelling the dipstick, it is a bit sweet. There is no foam on the underside of the oil fill cap. The truck drives just fine, but no heat.

I laid under the truck again last night for two hours trying to locate a source for the coolant leak. I suspected the heater core possibly because I didn't think the thermo would go bad this quick (although I didn't replace it again to find out if that's the problem). Didn't find the source of the leak, but did find some coolant dripping from the bottom of the metal pipe the connects to the heater hose and then wraps back around the block and goes to the lower radiator hose on the passenger side. Looked like there was some coolant streaks on the side of the head above that, but the exhaust manifold is in the way so I couldn't tell for sure where it was coming from (even with the heat shield removed).

So, my question is this: Does this sound like head gasket failure? Cracked head? just another bad thermostat? Other problem?

If I did blow the head gasket would the truck still be able to drive just fine? I was just getting ready to sell this truck when all this crap started happening.

I am not a proficient mechanic and doing a HG is WAY over my head.

so, if the HG is bad, which I think it might be (but it seems weird that overheating one time could cause this much trouble), is it better to do the HG, get a new head, or replace the whole engine. The truck has 156k miles on it, but the engine was supposedly "rebuilt" 25k miles ago...I say supposedly because I have no receipts or evidence of the rebuild...just the word of the previous owner. The truck has had a small oil leak since I got it at 150k, which seems odd of the engine was just rebuilt.

So, my toyota brothers, please throw me a life preserver.

ps. anyone want to show me how to do this work?

Kookadala

I would also check the freeze out plugs as that is a potential spot for coolant leaking. There is the chance that the head gasket can blow and leak coolant to the outside of the engine only, although that is rare. More typically there is coolant in the oil but that is obvious as the oil turns milky and foamy.

Overheating can cause head warpage if it gets hot enough for long enough. Try putting some black pepper in the radiator to seal small leaks or using alumaseal.

someoneusedmyname

Find the source of that coolant leak before you do anything. If you're leaking too much coolant you will have poor to no heat.

slim_slc

the thing is the coolant leak keeps evading me...and it's not major. Like I check the coolant before I go to work and it's fine...then check before I come home from work, and the overflow tank is still full, but when I check the radiator it is a little lower than in the morning. But, when I remove the cap I can hear fluid being sucked through the hose from the radiator to the overflow tank....don't know which direction it is going. I laid under the truck again tonight watching for leaks, found nothing.

Also, my truck is not overheating now, so that makes me think it's not the head gasket, but I don't really know. My temp guage never moves from all the way cold. It was 13 degrees this morning. I want my heater. Should I just replace the thermostat again? How is it possible that a thermostat can fail in two weeks?

About the freeze plugs...do you have to remove a lot of crap from the engine to get to them? I checked my manual and it says you have to drill holes in them to get them out...this is no good as this is my only car and I have to drive it to work every day.

wo is me.

again I repeat the question...if the HG is blown, wouldn't my driveability be effected? The truck is driving like a champ.

someoneusedmyname

I doubt its the head gasket, you may have an air lock or a blockage in the heater core. I've had with different cars, where there was an air lock and the coolant was not circulating properly and therefore the coolant was not passing by the temp sensor, so the engine was hot but no reading on the guage. Also a brand new thermostat can be defective,they should always be tested be installation, brand new faulty thermostats are more common that you think. If there is an air-lock the coolant leak will probably occurr when you are driving at low speeds with vehicle all warmed, and it will spew out the coolant reservoir for a bit. I'd check that thermostat is working, and that coolant is circulating and then that there is coolant going through the heater core.

slim_slc

good advice...thanks. I just took for granted that the new thermo would be good, especially since I paid extra for a fail safe one. It's hard for me to justify the 35.00 for the toyota part when the autozone one is only 5.00. I'll pull this one put and check it.

I've been trying to locate the hoses that go to the heater core, but I'm not totally sure where they are and I can't find a diagram in the chiltons manual that tells me. I could really use an exploded diagram of the cooling system for the 22re if anyone has it.

kc9

We've got the same thing happening on my '94 truck..22RE engine.
We just had the thermostat, antifreeze flushed/replaced last week after it was doing the same thing you describe.. No heat, eventually overheats, and
is missing antifreeze.

Just got back from meeting my son, and had to add about 1/2 gallon
of antifreeze/water mix. First thing I checked was the oil, and although
it's hard to tell, the dipstick is above full, which is tells me the
antifreeze is leaking into the oil pan. A blown head gasket would lead me
to believe I would see oil/water leaking OUTSIDE.. I can't see any evidence
of a leak OUTSIDE.

I'm thinking cracked block, manifold, or something I prolly don't want to hear.
Thanks !

Blair

Slim SLC : I'd look at the J-tube that runs towards the firewall and behind the plenum. Terrible spot to get to and a prime location for a hard-to-find leak. If not there, then maybe the casting (freeze) plugs located behind the cylinder banks. Three on the right side, two on the left. These plugs can get corroded, and begin to seep, then full-out leak. Mine were weeping (after I had the HG recall done) so I put some rad sealant (very bad practice) in and I'm not leaking anymore. I'll change them when I do the clutch. They are impossible to get to without unmating the engine from the transmission.

KC9 : You could be looking at a simple (not really, but better than a blown HG) timing chain cover hole, worn through by a loose timing chain. But that rising oil level sounds scarry.

Both of you should have a leak down test to ensure it's NOT a blown HG. My guess is that one is, and one is not (SLC slim)

hektikwon

Did you replace your water pump when you did the thermostat? I don't know much about the 22re but my 3.0 had a coolant leak that turned out to be a bad hose behind the engine that goes to the heater. I would look for something similar to this. Just my .02 cents

Yota4runner

I just fixed a leak on the top passenger side of the eingine, there is a coolant hose there that will leak right down the side of the block and drip on to the ground. It was hard to see,but once I got the truck running it leaked like a seive and I was able to notice it. But unless you were to look right at it it's very easy to miss.

kc9

Thanks for all of the responses.. I'll keep looking !!
The only thing that's troubling is that there's no evidence of anything
leaking that I can see.. well that, and the rising oil level. We leave it parked
and running on a white concrete pad, and no drips.. no nothing.
I'm going to drain the oil to better see if there's evidence of coolant leaking internally into the oil.

hektikwon: re: water pump.
No I haven't replaced the water pump as I believe it to be ok..
One, coolant is circulating.. I can see it moving in top of the radiator, plus
the heater is working (means the thermostat opened). Heater
hoses (in/out) get hot and are about the same temp. (I also reversed
flushed the heater coil last wk after the engine flush.)
I've been led to believe a bad water pump would either start whining and/or
begin leaking if it was bad. Plus, it would get hot in a big hurry.

How about a bad/clogged radiator ? All I can say is that the first quart or so that
came out during the flush was unrecognizable. It looked more like dark brown
beer than green antifreeze. I'm still thinking that there's possible corrosion
or a blockage either in the radiator or somewhere else in the coolant path ?

jreynold

1990 3.0 4x4 190k
I just got done swapping my water pump, rad, tstat, hoses, all due to the fan bracket pulley seizing. Never had a problem with overheating, loss of coolant.
Had same problem with coolant slowly disapearring. No coolant in the oil, whhheeww! It was coming slowly out of the j like hose at the water bypass. At first, it did not show any signs of dripping because the drip was slow enough it steamed off immediately. After a few times of driving it though it got worse and now it is a noticeable leak. Going to try to get at it without removing anything.

jreynold

I got to the j tube without moving anything, just took a little scraping up of the wrists, but no real problem.

kc9

Well, not coolant found in oil. No leaks anywhere, so that's good news.
Decided to replace radiator cap, and problem is fixed. The lost coolant was
apparently escaping and/or evaporating from the radiator.
DUH !!!!! A $6 part !! Didn't someone say it was something easy.?.. haha.
Thanks again !!

slim_slc

yeah, I replaced my radiator cap too. I think I have figured out that my coolant leak was due to the fact that I overfilled the coolant overflow reservoir......but I cannot test this theory, because my truck will not start now. It's been sitting dead for about a week now. I'll start a new thread about that. I think I'm going to have to take it to a mechanic. Dang It!