So I just had a "new" used engine installed in my 2000 GS300, at which time the wp and thermostat were also replaced. For some reason my radiator is leaking causing my car to over heat. I had the thermostat check- it works.
If I drive any distance over about 30 miles, the coolant in my radiator, as well as my reservoir drain pretty quickly. My mechanic did a pressure test which he says came out fine,. and he is leaning toward replacing the radiator to fix the issue. I guess my question is, is there a sure fre way to make sure its the actual radiator that is the problem before I replace it??

 

I am too dealing with coolant issues myself, just on the upper end of it. A thought though, since you didnt mention it in your post, Im just going to assume that there was no obvious signs of leakage to be found on the ground after parking? Since not, I would check your oil for a milky "coffee" look described in other posts when talking about the precursor to major engine trouble... but another thing to investigate is your heater core hoses. Since they have mountings very close the exhaust system/heat shield/engine block, any leakage will hit those and evaporate or soak in. leaving no trace and wont actively leak when the car is off. Try letting the engine idle with the heater on high and watching all 4 connections and look for any telltale signs of that. Trust me, it can leak surprisingly fast even though you seemingly tightened all your connections down to spec..

 

My apology epk1001.. there actually is usually a small amout of leakage on the ground after parking the car. It usually isn't much, but I assume thats because its actually draining as Im driving the car. Assuming the head gasket is still good bc it was just replaced, and the thermostat, and wp are all working well, does a leak coming from the bottom of the the car indicate anything?

 

its only when driving? have you tried letting the car getting to temp while its sitting and you check for leaks?

usually thats an easy thing to check

 

That's a good point.. I've only noticed it leak during, or after I drive it. I'll let it idle and get to temp and see if I can spot where it's coming from. Thanx man... I'll update after I check it out .

 

Hopefully youve found the source of the issue. If you havent yet, it may be worthwhile to stick a cardboard box or something large enough to cover the entire area of the car after you park and any drips would stain wherever they land to give you a better look at where its leaking. another thought came to mind after re reading your post. You said that the car loses coolant quickly after a trip around 30 miles. If your car doesnt lose coolant on shorter trips, maybe its the hose leading from your thermostat? If your thermostat works, then that distance would give the engine ample time to warm it up to temp enough to try and cycle it through the thermostat and maybe its leaking out through the hose?

 

i sort of had the same problem a few months back. would idle fine and reach operating temp and stay there. but as soon as i drove a couple of miles down the road it would gush out coolant and overheat. turns out my friend had put the thermostat in the wrong direction. so i would check that the thermostat is in the right way and check that off.

 

have you crawled up under the car and removed the bottom cover to inspect the radiator. There are usually pink crusty deposits around the leak area. Assuming you are using Toyota coolant.

 

Check your thermostat to make sure it's in the right direction. Another thing to check it's air trapped in the system. That could cause problems for sure. Or the radiator for sure. They re cheap . I bought mine from eBay at 56 dollars and I did replaced it myself . Took me 2 hours . Easy job and exactly fit. Good luck