I need some real help here guys, as I don't know what to do next.

Here's the story: This morning I went to a store came back home for a quick minute then left again. Sitting at a traffic light not two minutes from home I see my temp. gauge and it is nearly at the red area. So I crank my heaters and head back home thinking maybe my coolant level was way down (I had been having some coolant leak out of one of my hoses after driving for a while). I get home and steam is pouring out of the hose that goes from the radiator down to the thermostat housing. The steam is coming from the radiator end and there is coolant dripping from there. I add some more coolant into the reservoir which was nearly empty and head to checkers to get a new thermostat. I thought the thermostat had failed in the closed position and the fluid was backing up and didn't have anywhere to expand but the weakest sealed point on the hose. I install the new thermostat (180*) and seal and test drive again.

It works great. Temp. goes up to about 1/2 way like it always has. Then as I am driving down the road (40mph) the temp drops to 1/4 on the gauge. Then a minute later has gone back to the middle, then a little over, and then as I drive further it drops to a 1/4. As I continue driving it remains at 1/2 way. I get to another store I needed some stuff at thinking my problem might be solved. Shutting down the engine I hear the hissing again and check the hoses, again steam is pouring out from the same spot and coolant is leaking. I check the temp. gauge and at this point it is just under the first red line. So I go home with my heaters cranked and it still stays about 3/4 of the way up to a little over half the entire time. I go to checkers again and the guys suggests getting a new hose. I install the new hose and go for another test drive. The temp was right at the first white line (almost zero) when I started driving. Within 4-5 min of casual driving it is nearly in the red again. Again the steam and coolant.

What is going on here? What else can I check? I was told the thermostat only works if there is enough pressure, but I can't get it pressure checked until monday. Is there something else I can check? Should I use some of that quicksteel stuff that seals radiator holes? I thought I heard that that stuff can cause more problems than help.

Thanks for the help!

 

Thermastats made from the early mid 90's fail in an open state. This includes aftermarket thermastats.

I never believe a temp guage on a Toy. Years of use on the coolant heat sensor makes it unreliabile. Suggest changing it.

Here's my list of things that MAY be wrong;

waterpump (tired impellers means less coolant moving)
plugged radiator
Coolant (ethelene-glycol) mixture has too much water

 

Did you make sure to put the new thermostat in the right way? Maybe you put it in upside down by mistake? I know for me, I've almost made that mistake a few times. LOL! Are you reusing the O-ring that goes around the thermostat? They like to leak when you reuse them for a second time.

How are the freeze plugs on the block? Are they rusty and possibly leaking? I would fill the coolant level up and run it in park/neutral until operating temperature with the radiator cap off. That way, you'll see if you're getting coolant flow through the radiator core. If so, then you know the waterpump is at least working. It's not going to flow like a river, but you'll see some movement when the thermostat opens. Have you checked the two lower radiator hoses by the alternator yet? How about the small coolant hose that runs behind the block to other side? Any leaks there? If I were you, I'd get a genuine Toyota radiator cap. They're pretty cheap.

Please, please, please DO NOT use any of that "quicksteel" stuff to seal the hoses.LOL! Just get the proper hoses and be done with it. You can get hoses to fit at most autoparts stores.

Hope this helps!

 

Are you building a lot of pressure in the cooling system quickly? If this is the case you might look into the possibility of a blown head gasket

 

Thanks for the reply guys, I did install the thermostat the correct way (spring down into manifold) and I bought a new o-ring.

amusement, the temp. gauge might be wrong, but you know its a little too hot when steam starts to shoot.

mikedog, I will try the running the car without the cap to check for water flow, and I had planned to check the lower hoses today as well, just have to get that skid plate off and look.

What are freeze plugs? I'll check my Chiltons/haynes later but I don't know too much about cooling systems, just a couple things I picked up when working with my dad on his chevelle.

shovelhead, I hope I don't have a blown headgasket! I have the 22r, not the v6. I haven't seen any white smoke coming out of my exhaust. Shouldn't my oil have some water bubbles in it when I check it if the head gasket were blown?

 

Ok, so I let the car warm up with the cap off and it got to normal operating temp but there was no coolant even at the top of the radiator fins, and steam was coming up. So I added more coolant into the radiator until I could see it. then I started it up again and the truck remained at a little over a 1/4 on the temp gauge. It didn't rise past that, even after 10 min. So I drove it. Still didn't rise. I shut off the engine and was checking for leaks, and as I am looking the hose that goes to the thermostat, the one that was steaming and leaking before begins to do that, but not as badly. The temp. is reading about 1/2. Once I start it up again it quickly drops down to a quarter. Shut it down again and it rises up again leaking from that spot.

So do you think maybe the nipple on the radiator is broken? I am not sure how thermostats work, but maybe the system is losing pressure there, so when it is running, coolant is getting pushed by the water pump, but so soon as it is shut down, the pressure is dropped from the leak around the nipple and coolant doesn't keep going into the engine??? Thanks!

 

As far as the temp going up and down when you start it and shut it off is probably due to no coolant flow when the engine isn't running. That happens to me here all the time in AZ. If I run into a store for something quick and come right back out, the engine temp registers way up on the gauge cuz it hasn't been running and all that built up heat in the engine has to dissipate on it's own with no help from the cooling system. If I had left the truck shut off for a longer period of time it would obviously be cool when I come back to it. That just doesn't have time to happen with short stops, but the operating temp comes right back down shortly after running the engine again. I'd repeat the flow check that mikedog suggested, making sure you have the fluid level up where you can see it and starting with the engine cold. That way can be sure whether you see flow begin when the thermostat opens, unless you're absolutely sure you saw flow the first time you performed the check. Also I'd replace that hose that keeps leaking when it gets hot. It could be that as the pressure and temperature build in the system you're losing fluid there and eventually end up with low volume and inadequate cooling.

 

Replace it again? Its only been used twice...? I can try it though.

I will do the flow test again, I'm waiting for it to cool so I can change out my spark plugs anyhow.

 

Sorry, missed the part about the new hose. What do you mean by the "nipple"?

 

Its the part that the hose goes over. Its a tube with a lip on it thats attached to the radiator.

 

Gotcha! Yeah, It's possible you have a small crack there and are losing pressure,therefore, losing coolant and cooling capacity. Is the radiator old? Don't really know what to suggest other than the pressure test you're already stuck waiting on.

 

Plays with toys,

Any resolution to this yet?

 

Yeah! Inquiring minds want to know.LOL! Was it in fact the radiator causing all the trouble?

Oh yeah, I almost forgot. The freeze plugs are those 1" round soft metal plugs on the side of the block. I think there's about (3) of them on the exhaust side of the 22r/re block. It's assumed that if the block ever freezes over, the plugs would be the first to give away instead of cracking the block thus saving the engine. However, I've also read that the reason they actually exist is due to the casting process the foundry uses when the block is made.

 

You are absolutely correct my friend, I just read this weekend in my textbook. During older times, people thought those where freeze protection plugs, where to prevent the block from cracking, they would expand, as water froze...umm FALSE.

They are indeed used during the casting process, to help hold and shape the block, nothing more!

 

The upper radiator nipple, or pipe, is prone to cracking where it meets the radiator on your model year. Have a decent radiator shop solder it back together. Will be good forever.

 

I haven't had any real problem with it. Speaking with my dad he said the heating up of the engine after shut off is typical, because the fan isn't doing anything to cool the engine, and it hasn't risen up to high temps yet. It stays alot cooler than it ever has, which means the previous owner installed a higher temp. thermostat or I never had enough coolant in it.

I believe the nipple is cracked, but I am going to try liquid gasket around where the hose meets up with it, just in case its the hose. And then I will check with my mechanic about getting the nipple fixed.


Thank you guys for all the help! Hopefully the resolution won't be $$$ and I can get an exhaust saturday

 

I forgot to post the outcome... :pat:

Well, it was still leaking after shut down, so I went ahead and I pulled the hose back, then applied the RTV silicon gasket maker around the nipple right at the radiator, a nice 3/16" bead. I then pushed the hose up to the silicone, let it dry, and voila. I haven't had any problems with it since.

 

Plays_with_Toys,

Cool! Glad you were able to finally solve the problem. At least you didn't have to spend $$$$ to get a new radiator. And just to think, for awhile there we were suspecting the headgasket.

Are you still using the stock Toyota hose clamp? Or, did you have to use a screw clamp on it where it goes into the nipple part? Just curious.

 

Great work Plays-with-toys!!!!

 

I have screw clamps. The stock ones are absolutely horrible. They should all be banished far far away. I had one that couldn't keep a seal if its life depended on it on the lower radiator hose, and they are just a pain in the butt in general.

I should really sell the truck though... Its giving me such bad luck!!! First the radiator, now my exhaust is making this wierd ticking noise after shut off, and today I got a 4 point ticket for speeding, along with a $100 fine! Now begins the process of seeing whether to fight it or not... And no I won't sell the truck, unless insurance sky rockets and I simply can't afford it, but hopefully everything will work out, and that won't happen.