hey guys, i though i would share my experiences with the use of radiator stop leak

my FD was smoking more every day, and my coolant temps were getting high enough to the point where i wouldn't drive without my fans on (kept it below 90degC)

so i decided that i would go against alot of peoples warnings and opinions (most of them haven't used stop leak) and dump some stop leak in my FD, my only other option was to rebuild it with a very limited budget and be forced to only go after the coolant seals.

i started first by getting some Zerex radiator flush, Bar's leaks stop leak, and a gallon of Zerex coolant (not mixed)

i drained the coolant through the engine drain plug (my radiator plug is broken) and blew in the filler neck with my mouth until i could get all (most) of it out lol
then i added all water and the radiator flush, drained it. and flushed it again with only water.

next i added new coolant and water and bled the system. i waited for it to cool and i added the stop leak and topped off the coolant. the bottle says to idle or drive for 15-30 minutes. so i let it idle until it got to 80deg, then drove around town without exceeding 3000rpms. my coolant temp shot up to about 90deg and i had to turn the fans on

i parked it for about 2 hours and let it cool down to about 50deg.
when i started it i didn't notice any smoke at all
then i drove around town, up and down the highway, and through some fun mountain back roads. i didn't go over 4500rpm the whole drive, but i wasn't driving it like an old man either.
my coolant temp stayed at exactly 84deg the whole drive

so then i decided to do another test, the hot start!

here is the video http://www.youtube.com/watch?v=S0LGquTfohA


i just did this today so ill report back on how its holding up, let me know what you guys think

 

I actually did this before when I first bought my fd with a blown coolant seal....it stop the smoking but too bad the motor has already lost compression...so I didn't get to see how long it would last.

 

My friend Tom has had some luck using block seal. He went through a much more lengthy process of flushing out the system before and after the block seal was set.

He's still running strong.

Good luck

 

90 to 100degc is common in stop an go traffic with a stock ecu or untuned Pfc.

There is also a detailed writeup here or on one of the dedicated rx7 websites with a more lengthy proper process. look it up.

 

Using stop leak is a good stopgap measure - it will buy you some time for sure. But, the motor will HAVE to be rebuilt in the not too distant future.

Also, when the time does come, don't let the motor sit for a long period of time. Coolant will get into the combustion chamber and rust the seals in place, causing parts that could have been reused to become junk. When it's time, pull it, break it down, and rebuild it.

Dale