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Engine Overheating: Coolant leak but only blows cold air?

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BlackBessy97

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Discussion starter · #1 ·
Thank you all in advance for your help.

A couple days ago I noticed that my AC wasn't working so well, and then yesterday my engine began overheating. I cranked the heater in order cool off the engine while I found a place to pull off, but that didn't seem to do much.

After pulling over, I let it cool down, popped the hood and noticed that the coolant level was very low. I ran to a shop, picked up some antifreeze and filled the reservoir to the fill line, thinking it was just too low.

The car drove fine for the first couple miles but then began to overheat again, and when I tried to run the AC or heater, it didn't matter, only cool air was coming out (a little cooler than it had been running the other day). I pulled over once again, popped the hood, and the coolant reservoir was nearly empty, and I heard a very mild hissing noise. Not wanting to risk killing my engine, I called a tow truck and got it to my house, safe and sound.

I'm aware that this can be an expensive fix, but I'm only on a $300 budget.

My guess is that it's the fuel pump, but from everything I've read it could be a whole lot more than that. Here's my tentative plan, from all the internet wisdom (I'm anticipating someone tearing up this plan because I'm probably overlooking a lot more than I think):

My plan is to flush the radiator, order a new fuel pump and thermostat.

My plan is most likely short sighted but those are fixes I can do/afford.

The big question is where I should start: From which website should I order OE parts? What are good brands of parts to get and what should be included with, say, a water pump? What other info would be helpful in deciding what I should do, e.g., previous threads, etc.? Would pictures pictures be helpful, and if so, what should I be taking pictures of, or should I upload a video to YouTube so that you can see it and hear it in action?

Thank you all so much.
 
#2 ·
I think you mean water pump. Gas pump has nothing to do with it.

Most likely you have a leak somewhere. The fluid might be somewhere on the highway and gone by the time you stop. Can you try filling again and run it standing still, then look for leaks? If you are lucky, it is leaking from a hose which is inexpensive to replace. Little less lucky if it's from a punctured radiator. If it is from the radiator, then consult with other experts here. On my other trucks (GMCs), I use a radiator sealant that is poured into the radiator. It works, and is inexpensive, but those are old, simple big-ass V8 engines.

Second possibility is that coolant is running into your engine from a leaky head (or something). That's a really bad thing. Check your oil. Tell us what it looks like. Full? Thin? White froth or unusual color?

You did the right thing to stop as soon as you noticed the problem!

Good luck and keep checking here. We have several very knowledgeable people!
 
#3 ·
I agree, look for external coolant leak first.
If no sign of external coolant leaks but your loosing coolant then it points to head gasket, (coolant leaking into cylinders or into the oil, look for white sludge on the oil filler cap) , no heat from heater could indicate water pump failed or thermostats jammed shut.
Start with new thermostats or remove it completely if new one not handy,
If you have to replace the water pump then you should change the timing belt and pulleys too since they have to be removed to get to it, also change the various seals and 'o' rings to water and oil pump too.
I know that sounds a lot of work and it is but it will save you having to go there again,
Rock auto good source for parts, and I think if you can do the work yourself then your budget is sufficient,
Good luck!
 
Discussion starter · #5 ·
Update: I refilled the reservoir with coolant and started it up to see what it would do. I let it idle for a few minutes as I watched the coolant bubble in the reservoir, I thought that was a little weird. I gave it a little gas and ran the AC. It's still only blowing out cold air no matter what setting it's on. There are two fans near the radiator in the front, the one on the driver's side would go on when it was starting to get hot but the other one doesn't seem to do anything. It spins freely but I wonder if that should be spinning in conjunction with the other one, that would make sense to have those two fans blowing air on the radiator, but I dunno.

I drove it around the block and sure enough, in no time the temp. gauge quickly neared the 'H' by the time I got it back in my parking spot. The reservoir had stopped bubbling and it was still at the same level, so no coolant appeared to be lost in that short amount of time. I let the car sit for an hour, went back to check on it and the reservoir was empty again. I took out the coolant reservoir and checked for leaks—none. I checked the oil and the color and levels look good—no white sludge around the seal like the pictures I Googled.

I'm letting the car get nice and cool before I even consider popping off the radiator cap: I'm not a fan of 3rd degree burns. I'll post pictures of what my radiator cap looks like...it's a '97 so I'm betting that's probably part of the issue.

I can get a ride to the local autoparts store to get a new thermostat but I've read that I have to take my oil plug out to get to it. So I guess I'm looking at an oil change, new thermostat, radiator flush, timing belt, pulleys and water pump.

What size sockets should I get at the auto-parts store? Or should I make a separate trip to Home Depot for tools?
 
#6 ·
Could be that the thermostat is jammed shut, will not let the water flow, so the water in the heater matrix will not warm up the water.The rad overheats and the water is released through the rad cap. You can try and fill the rad up and start the car with the rad cap removed. As the water heats up you should be able to see a flow as the thermostat opens, Or try removing the thermostat and running the car again if the heater matrix starts to blow hot air and you do not loose any fluid its a good bet the thermostat is jammed. Place the thermostat in a small bowl or cup of boiling water you should be able to see it open.
 
#8 · (Edited)
One of the fans is for engine cooling, the other is for the air con, from what you say the engine cooling fan is working, that's the one on the drivers side, assuming it hasn't been interfered with at sometime ......
Don't let the gauge reached H, it shouldn't go beyond half way, if the fan does not cut in and drop the temperature then switch off.
You don't have to change the oil or remove the drain plug to change the thermostat (stat), you may find it easier to get to the stat if you remove the oil filter. Pick up a new rubber gasket at the same time you buy the stat.
No leaks or puddles under the car is not a good sign, sorry, it does rather suggest you are loosing coolant into the cylinders (and exiting through the exhaust since you have no signs of sludge or increased oil level on the dip stick).
However, change the stat before you do anything else, if you are really lucky then the coolant is leaking under extreme pressure because the stat is jammed, it may not be so bad when it's working again, doubtful but you never know and maybe you'll stick a can of head gasket sealer in before resorting to changing the head gasket, but we are getting ahead of ourselves......
If you are needing to buy tools then go to Lowes and buy Kobalt, make sure they are metric size, I spend half the year in SoCal, Kobalt have a lifetime guarantee and are regarded as pretty good tools, Craftsman are also good (Sears) but can be more expensive, there are better but considerably more expensive tools like SnapOn but you don't need them!
I have a couple of Kobalt socket sets, one set fits metric, imperial and torx and various others and has a step free ratchet handle, on the Toyota though everything is metric so a metric set will suffice.
You need a 10mm wrench for the stat, buy a set with open end on one end and ring on the other. A half inch drive in a socket set is best but a 3/8 th drive will be fine for what your doing, and cheaper.
Good luck!
 
Discussion starter · #9 ·
WARNING: I'm kind of an idiot, so laugh away.

I thought I had located my coolant reservoir, but no, I discovered that it was my oil...oh well, early oil change, no big deal. This didn't help me figure out how to drain the coolant out of the radiator. I undid the radiator hose and got most of it out.

Does anyone know the proper way to drain one's radiator? Help?

After removing the thermostat and replacing it with the new one (new rubber seal) and screwing it back in (which took a really long time. I started to put coolant back into the radiator and, alas, it all came pouring through the seal, or lack thereof, and yelled obscenities.

The first thing I'm going to do is get a better wrench, one that doesn't require a socket because the nut on the right side of the radiator hose is really hard to get on with a 'normal' wrench, it's too tight to use any socket wrench. I'm going to run to the Home Depot today to get a better wrench and then I'm going to diagnose how it's leaking.

What a mess.

I'm learning as I go...the hard way.

Thoughts?
 
#10 ·
The reason the resevoir seems to empty after the engine cools is because the rad cap has a valve in it that opens when the fluid expands so it can overflow into the overflow tank. When it cools the water gets drawn back into the radiator. i have had head gaskets go in two different ways. One way they can go is to let water flow into the cylinder head, this is easy to spot because it will be blowing a white smoke screen out of the tailpipe. The other way they can go is to allow exhaust gas to blow by the gasket, into the coolant passages and displacing coolant out into the overflow. If you idle the car until it is hot with the rad cap off and keep filling the rad with water, eventually you should stop seeing air bubbles, if they never stop coming then your head gasket has failed in the second way i described. You could also have a bad rad cap or thermostat. You can test a thermostat with a boiling pot of water, you need a pressure tester to test the rad cap, but they are cheap enough to just replace if there is any doubt but make sure you get the right one. A stuck open rad cap will allow the water to boil over because you will never build pressure in the cooling system.


edit: oh and the reason your heater blows cold is there's no water left in it. While you are diagnosing this, don't waste expensive coolant, get out the hose and use water.
 
Discussion starter · #11 ·
@tankd0g - I wish I could be that far ahead, unfortunately I'm trying to figure out the best way to put in the thermostat and I haven't had much luck. Should the stat and the rubber seal go into the radiator hose first or into the receiving end of it first? I broke the last seal I tried to put in, and also screwing on the bottom screw is really cumbersome, any suggestions? Should I tighten the top a quarter turn and then alternate on the bottom one? I'm not getting a good seal and when I wasted that antifreeze pouring it in there I saw it all leak out of there, I thought I had it on tight but I guess not, and it's really hard to see. Any help would be much appreciated.
 
#12 ·
BlackBessy97 said:
I'm aware that this can be an expensive fix, but I'm only on a $300 budget.
Click to expand...
Take it to a mechanic and use some of your budget because if you continue as you are........ putting water where oil should go, pouring anti freeze all over the ground and god knows what else, it going to cost you way more than three hundred dollars in the end.
 
#13 ·
BlackBessy97 said:
@tankd0g - I wish I could be that far ahead, unfortunately I'm trying to figure out the best way to put in the thermostat and I haven't had much luck. Should the stat and the rubber seal go into the radiator hose first or into the receiving end of it first? I broke the last seal I tried to put in, and also screwing on the bottom screw is really cumbersome, any suggestions? Should I tighten the top a quarter turn and then alternate on the bottom one? I'm not getting a good seal and when I wasted that antifreeze pouring it in there I saw it all leak out of there, I thought I had it on tight but I guess not, and it's really hard to see. Any help would be much appreciated.
Click to expand...

It's easiest to get at the bottom nut on the thermostat housing with a 10mm box end wrench by removing the oil filter. It's easier to put on straight if you do not attach the hose.
 
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BlackBessy97
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