I have a 2005 Toyota solora, I went up the mountains a couple days ago and my car ended up over heating. It kept over heating til I replaced the reserve tank. My car was working perfectly again til today. It started to over heat but not dramatically. I got home, parked my car and the temp of my a lot. What could it be
Overheating is typically caused by one (or more) of 3 things; insufficient coolant flow (including from too little coolant), inefficient coolant system (blocked radiator fins, bad fan, etc), or a mechanical failure/leak like a bad gasket.
A few thing to check if you haven't :
Are your upper and lower hoses in good condition? How to check radiator hoses If they are too old and weak, the suction can cause them to collapse and block flow. They are also a good place to check for leaks.
Do you have sufficient coolant of the correct type? How to check coolant levels This could be caused by a few things, such as a bad house or loose connection, a cracked hose port, cracked housing, or even just an open drain plug or petcock.
Is coolant being circulated?
A DIY way of testing is with the car on and at temperature squeeze the top radiator hose somewhere in the middle. If you can squeeze and let it go and feel the coolant rushing through the hose then you're fine. If you can't squeeze it or it feels too firm then you likely have a stuck thermostat.
NOTE: If your car is not warmed up at all, then the top radiator hose should be firm. So that is an important distinction to make.
- Do you have a head gasket leak? The most visible indicators of a possible head gasket leak are milky engine oil, or white smoke from the exhaust and consistently losing coolant without a major visible leak. There is more info here : What are the symptoms of a Blown Head Gasket?
If everything seems to check out on the basic things you can check easily, then I'd consider getting into doing some actual work.
There are many more potential causes for overheating, but they pretty much all boil down to the 3 I mentioned at the beginning.
Past this, you're looking at possibly buying parts, so if do, I'd do that on a cost gradient myself. Easiest/cheapest things first, I'd probably do radiator flush, clean exterior of radiator, replace radiator cap, replace hoses and clamps, replace thermostat, replace coolant pump - giving a few hours of use between each action to make sure the problem has been handled, or is persisting - and only continuing off the problem persists.
After at of those steps, you've really only got a few more steps, which would be replacing the radiator and replacing all the gaskets, most likely you'd go to a shop for those, because they are pretty hefty jobs (although the radiator replacement could be DIY if you wanted to).
If I get any specific ideas for your car I'll update my answer.