THSCC Forums

I recently bought a 2005 Civic and am working through a "to do" list of items. It has some coolant system oddities (sometimes doesn't put out heat inside when I know coolant is hot and temp fluctuation on gauge with tendency to occasionally run hot for a short period of time) that I believe are linked to a slow opening thermostat (or opens at wrong/too high temp), bubble in the system (needs to be burped) and "maybe" sludge or partial plug of heater core (it will produce good heat when it works so I suspect the heater core is OK). I am going to be replacing timing belt very soon and as part of that will be replacing the water pump and thermostat.

My question is around what is the general wisdom regarding coolant system flush. I am looking to do this myself. I have seen the following methods...

1. Flush with regular tap water from garden hose.
2. Distilled water only

In previous flushes on other cars, I have just used regular tap water via garden host. Clearly the idea with the distilled to to keep minerals out of the system. Distilled overkill? I suspect yes.

Given the high mileage I have no idea what has been done before, so am a little concerned about scale and other sludge buildup in the system. I was looking online to see what if any additives might help with a back flush. I found these...

1. CLR cleaner followed by some baking soda and water to neutralize (some say only use CLR on heater cores)
2. Dishwasher machine soap (non-suds soap)
3. Vinegar (assume followed by baking soda/water mix)
4. Commercial products (don't think there are many of these)

Thoughts and opinions?

Richard

_________________
Richard Casto
1972 Porsche 914
2013 Honda Fit Sport
2015 Honda Fit EX
http://motorsport.zyyz.com
Money can't buy happiness, but somehow it's more comfortable to cry in a Porsche than a Kia.

I'd use something like this: http://shop.advanceautoparts.com/p/peak ... nt=7690005

Prestone makes a version of the same stuff.

Unless you have horrible build up in the cooling system, this stuff should clear it up. Might want to backflush the heater core with a garden hose, I've seen heater cores get semi-clogged with random bits of plastic from the cooling system. Just put the hose on the end of each of the hoses going to the heater core and run water through it for a bit, and see if anything comes out the other end.

Distilled water is a waste to use for flushing, might be a good idea to use for filling/topping off after adding fresh coolant.

Sounds like air is trapped in the system. Have you ever heard of the "AirLift" system to bled the cooling system? It uses compressed air (through a venturi) to pull a vacuum on the system and it sucks the coolant into the void leaving no air. I have one and you are welcome to borrow it if you have an air compressor.

_________________
Vincent Keene
'06 Ford Mustang GT (track rat)
'15 Dodge Charger R/T (yeah, it's got a HEMI!)
'07 Ford Fusion SE (205,000 miles and counting)
'98 Chevy Z-24 (retired)
'93 Acura Integra (Team SWB 24HOL Car)

It does show classic symptoms of air in the system. I typically have been able to burp a Civic pretty well but if there is an easier way I am all for it. I had never heard of that tool and I appreciate the offer to borrow. I checked on Amazon and they are not super expensive and as you know every project is an excuse to buy a tool. I am going to order one!

Richard

_________________
Richard Casto
1972 Porsche 914
2013 Honda Fit Sport
2015 Honda Fit EX
http://motorsport.zyyz.com
Money can't buy happiness, but somehow it's more comfortable to cry in a Porsche than a Kia.

After using Aaron's, I bought one for myself off Amazon as well. Let me know how you like it.

_________________
Vincent Keene
'06 Ford Mustang GT (track rat)
'15 Dodge Charger R/T (yeah, it's got a HEMI!)
'07 Ford Fusion SE (205,000 miles and counting)
'98 Chevy Z-24 (retired)
'93 Acura Integra (Team SWB 24HOL Car)

I will probably use either the Peak or Prestone product (those seem to be the major commercial products). I really liked the idea of the dishwashing machine detergent (such as Cascade) as there seems to be a lot of people online who had had good luck and some say it works better than the commercial products. The CLR sounds interesting, but maybe a bit scary.

_________________
Richard Casto
1972 Porsche 914
2013 Honda Fit Sport
2015 Honda Fit EX
http://motorsport.zyyz.com
Money can't buy happiness, but somehow it's more comfortable to cry in a Porsche than a Kia.

I watched a YouTube video of it in action. The bonus is that you can also check for leaks in your coolant system (will it hold a vacuum). Amazon Prime FTW!

Richard

_________________
Richard Casto
1972 Porsche 914
2013 Honda Fit Sport
2015 Honda Fit EX
http://motorsport.zyyz.com
Money can't buy happiness, but somehow it's more comfortable to cry in a Porsche than a Kia.

Yep. If your system wont hold a vacuum it won't do jack. Therefore you might find a problem you didn't even know existed.

Prime rules!

_________________
Vincent Keene
'06 Ford Mustang GT (track rat)
'15 Dodge Charger R/T (yeah, it's got a HEMI!)
'07 Ford Fusion SE (205,000 miles and counting)
'98 Chevy Z-24 (retired)
'93 Acura Integra (Team SWB 24HOL Car)

Hi Richard,
I have a 2004 TSX w/ the 2.4 that I had to pull the rad to change the front motor mount...Pulled the rad a number of times without any issues but this time, no heat, the temp gauge all over the board...
Apparently you have to let the fan cycle on a few times to make sure that you've bled the system enough.
Easy enough to do but I must have rushed the refill of the coolant.
Hopefully this helps,
Chuck

If I am working on a cooling system of unknown age and I suspect that there might be sludge, I flush it as indicated, then put a mix of antifreeze and distilled water in the system, run it for a few thousand miles and then flush it again.

A couple of times I've found that the second flush gets as much gunk out as the first one did.

_________________
2004 Subaru Forester XT
1992 Sunburst Mazda Miata
1990 Mazda RX-7 (work in progress)
2000 Xterra SE