i have a 1990 toyota pickup 3.0 that has a severe leak. the problem is that i cant find where the coolant is leaking from. i pulled everything off thinking it was the water pump and the gasket on it looked pretty bad so i replaced the gasket and the thermostat gasket. thinking that i had fixed it i put everything back on and while trying to get it to crank over( doing this in 30 degree weather. takes awhile to crank it over) we realized that there was still a steady leak from the motor. i just cannot figure what would be causing it but it is making me very frustrated because i thought i had found the problem but i didnt. shortly before doing this the pickup had started slowly leaking coolant. this leak got progressively worse and worse to where one night i overheated the pickup to where it shut down on me. i know.... stupid me i wasnt paying attention to it. after letting it sit for the night i filled it with coolant and fired it up. had no problems but it was still leaking. has anyone else had this leak? i am completely lost as to what to do right now. any help would be greatly appreciated guys.... thank you

 

A radiator pressure test will help identify where the leak is located. Your local auto parts store may have the kit you can borrow for a deposit or a radiator shop can do the test.

A severe leak should not be difficult to locate.

 

What part of the motor is the leak showing up on? I had the coolant pipe under the intake manifold start leaking and it leaked off the front and back of the motor on the drivers side.

 

the reason it is so hard to locate is that it is on the front of the motor coming from what seems like somewhere behind the plastic timing belt cover that is on the front of the motor.... i will have to try that test. might have what i need laying around or can probably borrow it from a parts store.

the leak is on the front drivers side of the motor. i havent noticed in the back of the motor but i will check that when i look at it later today.

another thing i forgot to mention is that sometimes it will leak when sitting and it leaks when running. as soon as i put coolant in the radiator it will start leaking and sometimes it wont until i start it and it will slowly pick up speed on how fast it is leaking. it completely emptys itself within about 2 or 3 miles.

 

also rw how will it determine where the leak is from? wouldnt the pressure test just tell me that it is leaking?

 

Take the timing belt cover off and leave the engine off...the pressure forces the coolant out of the system. Once you see where it's coming from it should be much more apparent where it's failing.

Also, clean the engine bay with some degreaser before doing the test. It's much easier to trace a leak with clean surfaces.

 

ok. im working on towing it up to my fathers house where we have more tools and a better work area. once i get it up there and get the cover off i will work on getting my hands on one of those testers and i will let you guys know the results. thank you for the information.

 

Yes. Do that!

 

My 3.0 has the same issue, due to sub par coolant and minus 25°c weather, it seems to be leaking around the thermostat housing where the water pump meets the block, seems to me the water pump got damaged as there isn't a coolant trail above it, only below it.
so i will replace unit and see if its fixed