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Cream under coolant filler cap

Old 06-23-19, 11:47 AM
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Cream under coolant filler cap

Hello
I'm the owner of a FC Convertible

I noticed today that i have cream under the COOLANT CAP/ COOLANT FILLER NECK.
I HAVE NO OIL CREAM IN OIL FILLER NECK OR IN OIL DIPSTICK!

Also car doesn't smoke at all from the exhausts when i start it or even doesn't eat coolant in the reservoir! Coolant in the reservoir is clean

I was afraid that one of my coolant seal broke because of the cream under the coolant cap.

Cream is not brown as should be if it's a mix beetween oil and coolant but it's green as my coolant. I'm using a coolant called Arexon Rolin Fluid that has a GLITECH 4.100 patented additive.
Could this cream be this additive? Coolant is green and that cream is green.

See the photo please.

Car behaves normally. Engine never flooded.




Why the cream under radiator cap?
Thank you very much!

Last edited by Venturer; 06-23-19 at 01:31 PM. Reason: More details added
Old 06-24-19, 05:37 AM
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That looks like calcium deposits are collecting on the pressure cap. When is the last time that a proper coolant flush was performed?
Old 06-24-19, 07:16 AM
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Originally Posted by mazdaverx713b
That looks like calcium deposits are collecting on the pressure cap. When is the last time that a proper coolant flush was performed?
Hello and first thank you for your opinion

Made the last coolant flush on September 2018. And made the flush before on August 2016.
Since i own the car (February 2016) i run only for 2.500 kilometers.

When i made the first coolant flush the circuit was dirty with sediments inside. I used a circuit cleaner for both coolant flush

I don't know if i made the flushing procedure correctly: first i dropped the old coolant from radiator and from engine crankcase. Then i filled the circuit with tap water and the circuit cleaner. I runned the engine for 20 minutes. Then i dropped the water from radiator and from engine crankcase bolt, i filled and dropped the water 3 more times then i added the new coolant (with ENGINE OFF).

New coolant was water/coolant pre-mixed ready.

Problem is this: when i added the new coolant only 6,3 liters filled the circuit. I read that the coolant system of the FC Turbo was full with 8.4 liters. So in this case more than 2 liters are missing. Is it possibile that 2 liters of tap water were still inside the circuit (probably into the heater) and they produced calcium sediments?

How to full empty the circuit from the coolant?

Thank you very much.
Old 06-24-19, 06:28 PM
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Distilled water should be used. If you used tap/hose water then you have your answer.
Old 06-25-19, 05:35 AM
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Did you pull the small drain plug on the engine when you performed the coolant flush? You may be seeing the remnants of sediment and calcium from the flush to be honest. It wouldn't hurt to flush it again and even after flushing it, you still may see some calcium deposits floating around as its very difficult to get all of the old deposits and sediment out of he cooling system. The deposits love to hang on in the heater core and in the jackets on the housings.
Old 06-25-19, 06:08 AM
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Originally Posted by mazdaverx713b
Did you pull the small drain plug on the engine when you performed the coolant flush? You may be seeing the remnants of sediment and calcium from the flush to be honest. It wouldn't hurt to flush it again and even after flushing it, you still may see some calcium deposits floating around as its very difficult to get all of the old deposits and sediment out of he cooling system. The deposits love to hang on in the heater core and in the jackets on the housings.
With the "small drain plug" on the engine do you mean the bolt on the bottom of the crankcase? If It is, yes i drained the coolant out of the engine basement.
Old 06-25-19, 11:06 AM
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Originally Posted by Rotary Alkymist
Distilled water should be used. If you used tap/hose water then you have your answer.
Hello

I used tap water only for circuit flushing.

Then i added green coolant "pre-mixed" (coolant mixed with distilled water, i bought it ready to use). Problem is that perhaps 2 liters of distilled water are still in the circuit because even if i empty all the circuit when i fill it again only 6.3 liters of new coolant went in before filling the circuit.
Old 06-25-19, 12:34 PM
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Maybe someone used stop leak? It does look like it now that I think about it.
Old 06-25-19, 02:01 PM
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Originally Posted by Rotary Alkymist
Maybe someone used stop leak? It does look like it now that I think about it.
Why do you think that?
Car doesn't smoke or even eat coolant.

And i made 2 coolant flush since i own the car.
With 2 coolant flush shouldn't the stop leak go away?
Old 06-25-19, 03:48 PM
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I just remember tearing an engine down(rotary) that had stop leak used on it and it really stuck to the little jackets in the housing. I vowed never to use it on a rotary after seeing how easy it built up in the system.

Last edited by Rotary Alkymist; 06-25-19 at 09:04 PM.
Old 06-25-19, 06:24 PM
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Originally Posted by Venturer
With the "small drain plug" on the engine do you mean the bolt on the bottom of the crankcase? If It is, yes i drained the coolant out of the engine basement.
Precisely. Glad to hear that you did that. You may find you have to do more than one flush to get all of the crud out of the cooling system. Pretty common actually so don't sweat it.
Old 06-25-19, 06:36 PM
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Looks like stop leak on the radiator cap. Look for crusty/powdery deposits around hoses etc.
Old 06-26-19, 08:27 AM
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Originally Posted by Rotary Alkymist
Distilled water should be used. If you used tap/hose water then you have your answer.
Originally Posted by NCross
Looks like stop leak on the radiator cap. Look for crusty/powdery deposits around hoses etc.
But i flushed engine 2 times (in 3 years) since i'm the car owner. Can it be the stop leak persists even after 2 coolant flushes? Also as i said the car doesn't eat coolant or smoke white!
Old 06-26-19, 08:35 AM
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Originally Posted by NCross
Looks like stop leak on the radiator cap. Look for crusty/powdery deposits around hoses etc.
No powdery around hoses but when i bought the car the overflow tank was very dirty. It seemed to have some rust deposit on the bottom.
Also when i made the first flush some debris went out with the coolant: they appeared to be some sort of sand deposit. But they are not like sand colour, they were some very very small black grains.Can they be calcium debris?
Old 06-26-19, 02:16 PM
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Usually when the coolant had stop leak added it will dry into a crust around the leaky area after the leak stops and the engine heat cooks it.. An actual active leak would be seen as green wet coolant.
Old 06-26-19, 03:18 PM
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Originally Posted by NCross
Usually when the coolant had stop leak added it will dry into a crust around the leaky area after the leak stops and the engine heat cooks it.. An actual active leak would be seen as green wet coolant.
i don't understand exactly what you say. Do you mean that this green cream is an excess of leak stop that is circulating through the coolant circuit or do you mean that there is actually an open leak in the coolant circuit that produces this green cream?
But the car doesn't eat coolant. I tested it for 1.000km and the coolant level doesn't go down in the overflow tank.
if there is a leak do you think this has something to do with failiing engine coolant seals or, from the cream you see, can it be the leak is in a metal pipe and not in the coolant gasket?
Do you think i need an engine rebuild?

Thank you.
Old 06-26-19, 05:04 PM
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What you see is stop leak. If you don't have a leak someone did at some point. Stop leak will not solidify unless it finds a leak.

Dont worry about it. If you're not leaking you're fine. I would advise rotary owners to never use it though.

Itll be hard to get ALL of it out but its nominal. What matters is that you're not leaking and you're not overheating.

I wouldn't tear down unless you fail a pressure test and are certain that it is an internal leak.

Last edited by Rotary Alkymist; 06-26-19 at 05:07 PM.
Old 06-27-19, 05:56 AM
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Thank you!
Do you think this cream is truly a stop leak or can It be sediments inside the coolant circuit?

Do you think a stop leak product is good for fixing coolant seals leak? Or is It good only for fixing pipe leaks?

If my damage is a leak in a pipe It will be very good because an engine rebuild is not needed!

And also do you think a stop leak will be a permanent fix?
Does a stop leak goes away after many coolant flushes? I mean not the exceding stop leak that still runs in the cicuit but the stop leak that closed the leak!

Thank you.
Old 07-07-19, 11:10 AM
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I personally do not believe in stop leak. Im not sure anyone could say that it will hold indefinitely. My father always told me don't worry about things that haven't happened yet. Just monitor your levels -something an rx owner should be doing daily and you'll be fine.
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