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Rust Clogged Radiators - Flush with CLR rust remover
Surprisingly this hasn't been discussed anywhere on rx7club.com that I can find.
Most people say just replace, upgrade, or rod-out your radiator when you begin seeing coolant spikes and big temperature differences between the upper & lower radiator pipes. I want a "fix what you got" solution to remove the rust particles clogging my radiator fins that no coolant system flush will fix.
So here's my current conversation on this from the fc3s e-mail list. I'm planning to do what Felix recommends below pretty soon. My only concern is the rust remover touching plastic parts of the radiator. So I'll check into that next.
BTW - Everyone should install a REAL aftermarket temperature gauge so you can catch this stuff before you break a coolant seal.
Originally posted by vaughnc
----- Original Message -----
From: "RX-7 Rotary Car Nut"
Sent: Saturday, March 13, 2004 12:46 AM
Subject: Rust Clogged Radiators - Flush with CLR??
OK I've got 2 cars now that have rust clogging the fins causing temperature spikes in warm weather. Both have 150-175K body miles, both show 20-30 degree temperature differences between the upper & lower coolant passages.
Both cars drain clean, have new thermostats, and new fan clutches, and good working water pumps.
A friend recommended filling the radiator with CLR for 3 days as it disolves rust. Of course I'd drain the coolant first and block off the upper & lower coolant passages.
Any thoughts on this? I'd like to avoid paying a radiator shop for roding the radiators, acid cleaning, etc... This sucks antifreeze rusts your radiator internally. You'd think there'd be a coolant filter or something
Date: Sat, 13 Mar 2004 02:05:04 -0500
From: Felix Miata <**********>
Subject: Re: Rust Clogged Radiators - Flush with CLR??
No filter needed when you replace the coolant before it wears out, normally well before 3 years of age.
The problem with radiator shops is finding one to actually do what needs doing and/or not waste your time convincing you the only appropriate course of action is to buy a new core. There aren't any like that around here any more.
Last time mine needed cleaning I started with CLR (after removing my radiator from the car) on recommedation of my local A/C shop. I wasn't satisfied that 28oz of the $4.99 stuff was high enough concentration, so after running that a while I went to Home Depot and found an equivalent product sold by the gallon and used 3/4 of that.
I don't remember the name, but the receipt says 021709370478 RSTSTNRMVR
$9.98. Running cooler than ever now.
You don't need to soak the entire radiator in the stuff, just the inside where the rust is. Remove the radiator and lie it flat on the ground with the connections pointing upwards. Pour in the stuff until if reaches the top of the connections. You might want to tip it slightly as it fills to remove air, then lie it down as the lower connection overflows.
i wouldnt do it just for the simple fact that other (probably better) cleaners would work fine and are cheap, but what if you washed it out quickly enough? i'm really not too worried about it. it was a half joke half serious post. i may buy a 20oz (591mL) coke and dab it on a rag to clean a bit of rust flakes off a turbo. its brand new, but the exhaust side has a tad bit of rust.
Originally posted by NZConvertible You don't need to soak the entire radiator in the stuff, just the inside where the rust is. .....
Don't want to leave the radiator cap on and I doubt my home-made plugs will keep the liquid in. So I figure just buy a near-sized container, use home-made plugs & fill the radiator up to remove any air, fill container up enough to cover the radiator, dunk the radiator, remove home-made plugs.
I'll give it a try though and see if my plugs can keep the stuff in so I won't waste product.
I know I could pull the hoses & radiator out of the engine bay & krimp the hoses, but I'd have to remove the low coolant sensor on the bottom of the radiator (hole) so the sensor won't be damaged. I don't want any rubber exposed to this stuff, so no radiator cap or hoses will be attached.
I was thinking of balling up some aluminum foil to shove in the radiator holes, but it would be hard to get a good tight fit on some of the holes.
You right, I don't want to waste product by filling a 55gal washpan, so I'll come up with something like wrapping the radiator in plastic for a watertight seal so the water won't spill into the washpan.
BTW - this stuff powder, so I'll start with the recommended strenghth of 1cup|1gal
You could put replace the level sensor (top of radiator) and temp switch (bottom of radiator) with bolts and replace the radiator cap with a cheap filler cap. No hoses need to be attached and nothing needs to be crimped. Easy.
yeay that sounds good, I could probably find a 1/8" or similar fitting to plug up the sensor holes. Luckily I just bought a thread pitch ruler so I can figure out what size & pitch the bolt shaft is without dragging them down to the hardware store.
Ideally the radiator should be right side up so the crud will fall down & drain out of the lower radiator hole. So I'll probably still use home-made plugs for the upper & lower radiator holes.
I'm trying to track down the "mystery product" Felix Wankle keeps talking about for rust removal. All I know is his receaipt from Home Depot says 021709370478 RSTSTNRMVR - $9.98 He said it worked wonders, so I'd prefer to use that instead of the stuff above.
I don't suppose you've tried that Iron Out stuff yet, vaughn, and if so how'd it go? I saw that stuff sitting there at home depot today and considered it. I didn't realize it was a solid that you mix yourself.