boiling out/pressure testing rad...

Trying to make my '98 reliable for NY/Florida trips, have a five year old gdi in it, no problems at all.

With all the company takeovers and confusion about metal tanks and such, figuring having a rad shop do the above procedure might be better than a new rad.

Any thoughts?!?

Thanks

Drain it, refill with water, drain it, do it a couple of times to get all the old antifreeze out. Dump in a bottle of the prestone cleaner, the 7 hour kind, refill with water, burp it, and drive it during the week. Drain it, flush it a couple of times to get all the cleaner out, then on the final drain dump a gallon or two of distilled water in and drain that. That should get all the chlorinated city sludge water out.
Dump in a gallon of 100% antifreeze, then make up your mix and start filling it.
Remember to take out the overflow tank and clean that out too, I found a sock on a screwdriver or paint stirrer will reach the bottom of the bottle, let it soak after spraying it with fantastic or some other cleaner. Remember to use the heat too so the cleaner gets in there too..

But what about the pressure test, won't that reasonably assure that somewhere down I95 I don't spring a leak?

mikeny59 said:

But what about the pressure test, won't that reasonably assure that somewhere down I95 I don't spring a leak?

Click to expand...

Whats a pressure test going to prove ? If you have a functioning rad cap it won't go over 18lbs anyway and when the coolant gets hot it expands, pushes the cap up and flows into the overflow tank, as it cools down it pulls the coolant out of the overflow tank back into the rad. Pressure as such is not really involved there, it's volume.
You can buy a prestone testing kit for about $80 with all the adapters in a nice plastic case. It will not only pressure test the cap but it will allow you pump the system up to whatever pressure you want to so you can look for any leaks. I think I have used mine maybe 5 times in the 10 years I've owned it.

Just remembering back in the days ('80's) when I was a "mechanics' helper", when someone came in w/leaky rad, that's what we did to see if the rad was salvagable or had to be replaced.

After you mentioning the prestone kit, red flag says why push pressure artificially high, more damage than good may be done...

About two years ago installed the hose fitting from prestone's back-flush kit, did a napa w/p and f/c, factory t-stat, distilled water, etc... and the seven-hour stuff, except just added it to the radiator after dropping a bit of coolant.

That w/water wetter made a tremendous difference in cooling, but can't single out one thing as the best...

Thanks for the refresher on rad caps :shhh: