Heat problem with an 89' yota..

[Crazy_Eddie]

First of all I know this is a truck site, but I thought I'd run this by you guys anyway.
The heat in my father's 89 camry stopped working last month. Now that it's getting cold here he needs to have his defrost working. He stopped by and I had a half an hour to take a look at it.
It appears to be a pretty simple system, basically it looks like the coolant flows from from the block (opposite side of the water pump) to a valve (that is mechanically opened by a wire that's connected to a knob in the cabin) that is mounted on the firewall. From there it looks like it flows to a fitting on the firewall that I'm assuming goes to the heater core and then the other fitting in the firewall returns the coolant back from the core to the water pump side of the block where the t-stat is.
I'm no mechanic so I could have the coolant flow to the h-core backwards.
The car has 200k on it and doesn't over heat. He said it actually looks like it runs a little cooler than before, but it gets up to running temp. I don't know if this would be caused by a bad t-stat.
Aside from replacing the t-stat and the h-core going bad and needing replacement I was thinking there may be a problem with the valve that opens to let the coolant into the h-core. The arm on the valve does move when you adjust it in the cabin. I was thinking to test it by disconnecting the hose that connecteds the core to both sides of the engine and hooking it up to a garden hose to see if the valves let the water through; I don't know if this is a bad idea??, but I do know that the hoses look original and if I wanted to do this or replace the the valve I'd have to get new hoses and clamps. Granted if ti doesn't let anuthing through it could be a bad h-core, but I'd be able to figure that out by disconnecting another hose.
Regardless, what should my first step be? should I go a replace the t-stat being that it's probably the cheapest way to go and work from there?

Thanks for any input..

-e

[Adams plowing]

i just had the heat go out in my dodge was a thermostat problem i would suggest to start out with that there only about $5 make sure to put a new gasket in with it when you change it though. becides even if it isnt the problem it wouldnt hurt to have a new one in.

[CT18fireman]

It really wouldn't matter what way the flow is throught the heater core. I would suggest that you replace the stat. While you have the system open flush it out using a garden hose. Remove bothe hoses going into the core and flow water through. You should get a good flow. If not try the opposite direction trying to remove any blockage. If you cannot get a flow then the heater core is bad. Continue flushing all hoses, radiator and the engine. Fill with water and make sure you get all the air out. Let warm up. If you do have heat then drain and add the proper ratio of coolant. Let us know what happens.

[wyldman]

It's probably the temp control valve.You can feel the heater hoses once the car warms up.If it feels hot right up to the valve,and then gets cold,or cooler,it probably the valve.If it's hot on both sides of the valve,and cold coming out of the heater core,then the core is plugged.If all the hoses just get warm,but not hot,then it's a t-stat.

For the cost of a t-stat,you could start by just throwing one in.Make sure you get any\all air out or it will hide in the heater core and you won't have heat.

[Crazy_Eddie]

I'm going to do the t-stat as soon as I get a chance.
What's the best way to make sure you have all of the air out of your cooling system? The reason I'm asking is it felt like there wasn't any pressure in either of the hoses that lead to the h-core. I was thinking that maybe some crude got stuck in the hose and is blocking it, but the heater core is the highest part of the coolant system so that would be a good place for air to get trapped..

Thanks again guys..

-e

[wyldman]

Fill the system slowly.Jack up the front,or park it on a steep incline so the rad is the highest point.

You can also take off one of the heater core hoses and fill slowly till all the air come out.

[CARDOCTOR]

if the cars a 4cyl
the stat where the lower hose attaches to the block
no gasket uses an o-ring

let us know if that resolves the problem



cardoctor

[Crazy_Eddie]

I had the car parked on an incline and jacked up the front end to try to get the air out of the cooling system. It took about 10 minutes and a little less than a qt of coolant, but I'm confident it's all out.
I can feel some heat, but it wasn't were it should be..

Get this, I'm such a rookie.. I went to remove the t-stat (two 10mm nuts) and could only get one off. The second one was in a tight space so I couldn't 1/4" drive socket to fit over the nut. I went to reach for my 10mm box end wrench, but only found a 9 and 11mm; note to self, never lend anyone tools.
The AC compressor was in the way of the socket wrench, being a rookie I wasn't going to remove it. I'm going to pick up the right wrench or may a swivel box end wrench (if there is such a thing)and get to it asap..

Question regarding replacing the t-stat. Would a faulty t-stat which remains partially open cause less flow to the h-core? In trying to understand how a t-stat could case a heating problem this is my only theory.

thanks guys..

[wyldman]

A t-stat that is stuck open will have little or no effect on the flow going to the heater core.The reason you would have poor heat is that the engine is running too cold.The t-stat keeps the motor at normal operating temperature,and only opens to allow water into the rad to be cooled.If it's open all the time,then the water is always being cooled,and never gets hot enough to produce decent heat from the heater core.

You should be able to feel the rad hose get very hot when the stat opens if it's operating correctly.Start the motor cold,and you should feel the heater hoses getting progressively warmer and the temp gauge will go up slowly.The rad hose should be cool at this point.When the engine reaches operating temperature,the stat will open,the gauge will drop slightly,and the rad hose should get hot.If the stat is bad,you will not see the heater hoses get very hot,and the rad hose will slowly increase in temperature almost like the heater hoses.

[Crazy_Eddie]

My father met up with one of his old world buddie's who is a mechanic the other night. Vlad (my father) said it took the guy an hour to get the nut I was struggling with off, made me feel a little better.
Anyway, I think he's going to have the guy look at it in his shop this weekend. If it's a problem with the heater core, he'll fix it..

Thanks for the help guys..

[Crazy_Eddie]

It appears the problem was crud buildup in the cooling system. The h-core was blown out and that fixed it.

Thanks for all of the help..

-e