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white paste in coolant system
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peaceablegarden
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Oct 1, 2011, 7:03 AM
Post #1 of 12
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white paste in coolant system
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My car guy and I are completely stumped.
Details: 2004, Scion xa, 70K, standard, well-kept
History: Heat stopped working, upon inspection of radiator cap found a white thick pasty substance. Found leaks in radiator. Car did not overheat at anytime.
Work done: Replace radiator, flushed system (chucks/pieces of white substance came out), added new coolant, heat still did not work. Drained and flushed system again, replaced with straight water, ran car and it heated well, drained. Filled again with radiator flush and water, ran and heated well. Left water and flush in system 2 days. Less than one hour of driving resulted in complete radiator failure (we actually believe we had a defective radiator). Flushed (more white chunks/pieces came out) and added new coolant, heat is not working again.
It appears that whatever this substance is that is solidifies in coolant but dissolves in water (heat works fine running coolant system on straight water). It does not seem to be building up under the radiator cap any longer, but does appear to be building up in the heater core or at least that's my theory.
We do not believe this is a blown head gasket. I'd welcome any thoughts. Thanks.
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Discretesignals
Ultimate Carjunky
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Oct 1, 2011, 8:58 AM
Post #2 of 12
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Re: white paste in coolant system
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I don't think that you are supposed to leave the flush in the system for that long. Might be why the radiator failed. You also have to understand that the water pump seal is lubricated by the additives in the antifreeze. Running straight water and flush probably doesn't go to well with the water pump. Time will tell.
White substance can be one of two things. Oil from either the crankcase or the thermostat wax pellet came apart. Since the top of the engine is fed oil through a passageway between the engine block and cylinder head, a head gasket problem in that area could cause engine oil to get into the coolant ports.
The thermostat has a wax pellet that is used to open and close the thermostat's valve when the engine's coolant reaches a predetermined temperature. Probably wouldn't be a bad idea to pull the thermostat and inspect it.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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peaceablegarden
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Oct 1, 2011, 9:40 AM
Post #3 of 12
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Re: white paste in coolant system
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Thermostat has been replaced. Sorry, forgot to mention.
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Discretesignals
Ultimate Carjunky
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Oct 1, 2011, 9:52 AM
Post #4 of 12
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Re: white paste in coolant system
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Can you take a picture of the substance and upload it to a picture hosting site and send us the link?
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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peaceablegarden
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Oct 1, 2011, 10:54 AM
Post #5 of 12
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Re: white paste in coolant system
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Sorry, alas no. It has been cleaned out. What I can tell you is that it is sort of pasty and was not mixed in with the coolant but rather collected around the rim of the radiator cap and was coming out in bits when flushed. It was quite white.
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Discretesignals
Ultimate Carjunky
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Oct 1, 2011, 11:15 AM
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Re: white paste in coolant system
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From your description is sounds like oil in the coolant. Since you had it cleared out, you'll have to see if there is a reappearance later. If there is, you'll have to do some investigating.
Are the coolant hoses to the heater core hot when the engine is at operating temperature? Have you tried back flushing the core? Make sure you use Toyota Super Long Life coolant (pink).
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
(This post was edited by Discretesignals on Oct 1, 2011, 11:16 AM)
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peaceablegarden
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Oct 1, 2011, 12:24 PM
Post #7 of 12
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Re: white paste in coolant system
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No hoses are not hot, though today after an hour's drive, there is some improvement in heat. It's certainly not fully back but probably about 40% better than nothing but still a way to go. Once heated up you can turn on the head and it will be hot for a couple of minutes until it cools off again.
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peaceablegarden
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Oct 2, 2011, 2:37 PM
Post #8 of 12
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Re: white paste in coolant system
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I believe we may have found our answer. Apparently coolant, if old, can create a residue - silicate (though we did a flush and replace about a year ago). I think this is what the white chalky, pasty substance was we found that seems to be gumming up the heating core. It might also account for why there is heat when it runs on straight water and not with coolant. My concern is this. If we replace the heating core, frankly after flushing three times with little or no help doesn't seem to be working, my fear is that there is still this old residue still floating around that would clog up the new heating core. I'd welcome thoughts.
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peaceablegarden
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Oct 3, 2011, 4:18 AM
Post #10 of 12
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Re: white paste in coolant system
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Yep, we get that now, of course too late. I am still wondering about how to make sure all the silicate is out of the system before replacing the heater core or how to get all the silicate out of the heater core so we don't need to replace it.
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Discretesignals
Ultimate Carjunky
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Oct 4, 2011, 7:21 PM
Post #11 of 12
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Re: white paste in coolant system
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You sure it is silicate, because toyota super long life isn't susposed to have any silicates in it. Not really sure how you would go about getting that out without multiple flushings. Did you remove the heater core hoses and try backflashing the core out? Your hoses should be hot for the core to work. Maybe you have air pockets trapped in the coolant system.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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