cztheman64

My radiator is weird to say the least. It leaks on and off, and earlier today the antifreeze was boiling into the antifreeze reservoir and once i let it cool off it had all gone back into the radiator and was fine!
Has anyone had anything like this happen?
Should i just go out and get a new radiator and hope for better luck with it?

I have a '93 4runner 4x4 v6 3.0l

abecedarian

replace the radiator cap and see how it goes
if the problem goes away, it was a weak rad cap.
if it continues, there may be an issue with the thermostat or possibly a head gasket leak.

cztheman64

well ive replaced the cap because the last one that i had was a POS and i even tried putting some of the stop leak stuff in there too but that didnt do anything this time either!

abecedarian

so let's explain this-
pushing coolant into the reservoir means that the pressure in the radiator has exceeding the rating on the radiator cap.
sucking coolant from the reservoir into the radiator means that there is vacuum in the radiator (don't argue with me, just listen) and it is sucking coolant back from the reservoir into the radiator

what we have to figure out first is why the pressure in the radiator has exceeded the cap's rating.

Now, if this happens all the time, and you are not losing any coolant... it is perfectly normal. Coolant expands when it is heated, and contracts when it cools off. This causes coolant to flow into the reservoir with a warm engine and causes coolant to be sucked back into the radiator as it cools down. PERFECTLY NORMAL!

Now, if you are finding that you have to add coolant over a week or month or so, there is something else going on.

Matt16

I thought I was using coolant until I noticed that the drain plug was shot. As for your problem, it kind of sounds like a weak rad cap.