Recognise Coolant Residue? Blocked heater cores.

[mightymousetech]

Had an MDX in the shop. Signs of plugged heater cores (front and rear) and partially blocked rad (hot/cold spots). Tried flushing with CLR, degreaser, citric acid to no avail. Ended up replacing both heater cores and the rad, along with a new thermostat and water valve. Now that the job is done (ugh), I pulled the bottom tank off the rad, and found this residue. It is like a gritty, slimy jelly. The vehicle did have aftermarket, non Honda Type 2 coolant. No idea what it was, smelled terrible, was greenish in colour. Anybody seen residue like this?

 

[Snagglefoot]

It's Flubber!

 

[Chris142]

Stop leak?

 

[rshaw125]

Looks like what was in my Buick courtesy of Death-cool.To flush it out I drained the death-cool and filled with water. Drove it for two days (Summer) ran the heat and drained, repeat.

 

[mightymousetech]

I suspect it may be silicate/phosphate precipitate from using an improper coolant.

 

[CT8]

Mixed coolants?

 

[mightymousetech]

Originally Posted By: CT8

Mixed coolants?

That is my feeling. Customer had his timing belt/water pump done a year previously at a independent garage. Sucks because the heater core/rad job required 18 hours, and nearly $2k in parts, and that was being very generous to the customer.

 

[Kestas]

It looks a lot like water glass from the silicated compounds in "green" coolant. Citric acid should have taken care of it. Isn't this why they used to rod out radiators way back when?

 

[WyrTwister]

Our water is very hard with lime / calcium deposits . That is why they used to dod out radiators when I was young . I have 2 cars with DexCool . If I was to switch , what would be the proper coolant ? Thanks , :-)

 

[dogememe]

Originally Posted By: WyrTwister

Our water is very hard with lime / calcium deposits . That is why they used to dod out radiators when I was young . I have 2 cars with DexCool . If I was to switch , what would be the proper coolant ? Thanks , :-)

Keep the dexcool, there is nothing wrong with it in gm vehicles as long as it's maintained properly and not mixed with non-dexcool coolants.

 

[Snagglefoot]

Originally Posted By: WyrTwister

Our water is very hard with lime / calcium deposits . That is why they used to dod out radiators when I was young . I have 2 cars with DexCool . If I was to switch , what would be the proper coolant ? Thanks , :-)

Distilled water and more Dexcool. I run Dexcool in my 2008 3/4 ton suburban. I won't risk changing to something else. It's running fine. Changed it once, will do again next year.

 

[Rand]

Originally Posted By: dogememe

Originally Posted By: WyrTwister

Our water is very hard with lime / calcium deposits . That is why they used to dod out radiators when I was young . I have 2 cars with DexCool . If I was to switch , what would be the proper coolant ? Thanks , :-)

Keep the dexcool, there is nothing wrong with it in gm vehicles as long as it's maintained properly and not mixed with non-dexcool coolants.

And not run low, and kept fresh, and in good condition, and a good radiator cap. Yep alot of ands... Deathcool works great until it doesnt. It has many advantages. to old green

 

[Snagglefoot]

If you're really paranoid, buy the Dexcool from the GM dealer. Wasn't much more than the aftermarket.

 

[Snagglefoot]

Fresh Dexcool s a bright orange and looks sort of pink or red when inside the plastic reservoir. The part number on the jug is the Canadian part number.

 

[dlundblad]

Could be tire slime?

 

[DoubleWasp]

Heater cores can be dodgy on flushing them. Too many tiny passages. Seen too many that would open up, only to clog again. Get that same problem with the coolant side of marine heat exchangers in badly treated systems.

 

[mightymousetech]

Well, after sitting out in the air for a week, the residue has turned into a nearly pure white powder.