I would put radiator flush in the heater core and let it sit overnite. Use a small length of hose to join the heaer core outlets.
Flush with clean water and use pressurized air .
Don’t rule out a poor flowing radiator. You stated the hoses had different temperatures.
Thermostat should be 192-195 degree one. A 50/50 antifreeze water mix is also critical to thermostat opening.
The oem thermostat is 180 and that is what is in there. I would think if i had poor flow thru rad, i would have an overheating problem.
Hi, came across this thread when trying to diagnose my own problem. I have a 99 RAV4 in Longmont, Colorado with 160k miles on it. Driving at low temps my car stays cold until I come to a stop then it warms up and the heat feels great. I am pretty sure I don’t have a blocked heater core, but possibly a stuck open thermostat. When I start driving the already warm car cools down as indicated on my temperature gauge. Running normally the needle is in the middle of the gauge, but when driving in cold weather <=20 degrees the needle almost hits the stop at the bottom of the gauge. I noticed this today when driving through some freezing rain. If I went over 20 mph the cooling system worked too well and didn’t let me melt the ice off my windshield. At stop lights and lower speeds it melted just fine. How does your temp gauge look when driving?
I think I am going to replace my thermostat and see if that is the problem. I’ll keep you updated.
Yep, you have a thermostat issues, pull the oil filter off then you can get to the right bottom bolt easier with a wrench. Good luck, I wish mine was an easy one. I have been in and out of this thing, still not sure about it. Before you change the thermostat, make sure the fans are not staying on, heard there was some issues with that happening. But it does sound like a therm issue.
Definitely not the fan. Mine is plenty loud, I believe it was replaced in a front-end collision I had 5 years ago (along with new radiator and hoses) and I don’t hear it kicking on very much at all. I’ll pick up the thermostat tonight but probably won’t be able to get it in until Saturday(2-5-11).
What brand thermostat did you buy? Do you think yours might be defective? I conveniently have O’Reilly(store brand: Murrays), Advance(Beck/Arnley) and Autozone(Duralast and Failsafe) nearby. I used to work at Murray’s in Ohio and they used to carry non-store brands, but now it seems they have switched since O’Reilly took over. I have had decent experience with Duralast products, but not specifically thermostats so I’m hesitant to go with that. Beck/Arnley is a brand that I have heard has a decent reputation, but I have never used their products. Or, I can truck it over to the Toyota dealer where I have a 10% off discount since I purchased a car from them.
Any suggestions? I am leaning toward the Toyota(Denso) part, but if I get lazy or forget to go that direction after leaving work I will go with Beck/Arnley unless you have a better idea.
I use Staunt, just preferance, Make sure it is quality and youll be ok. B&A is good.
I have kind of the opposite problem in a sence, the engine cooling is all working perfect, jsut heater suck. I am looking for a core but small town, nobody carries anything in stock, with this cold front pushing thru i was going to try to get it done tonight but cant find one. You are gonna freeze in yours two. Sound like this cold front pushing thru tonight is going to be ugly cold. You are supposed to be colder than i am. We are at 29 right now. I am in Salida, my brother lives in Longmont.
First you have to prove to me that oem thermostat is 180. All your sensors work off 190 degrees and up. You will not necessarily have an overheating problem, specially in winter time.
I have been working on cars for 36yrs. Master ASE tech.I haven’t seen a 180 thermostat in vehicles since the 1980s.At least not what the manufacturer installed.
When it comes to Toyota, use the factory thermostat.
Who installed the thermostat? Is it pointed in the right direction? What method was used to purge the air from the system?
Well you can look it up like i did, OEM is 180. Keep in mind it is a Toyota. I have put in an OEM thermostat, yes it is in the right direction, i used the park on a hill and the funnel method to burp.
Looks like it is a core issue, i went out and swapped the lines on the core, i have 25% better heat than before. I ordered a core and will put it in this weekend, then we will see.
Has anyone tried flushing the heater core? Here’s a video: https://www.youtube.com/watch?v=dcL_0TWeZJY
How hard is it to notice the thread dates?
Apparently, yes it is.