"Roundel" tech art: coolant change vs head gasket failure

[Gene in NC]

BMWCCA "Roundel 12/05 p128 has tech article on relationship of coolant change interval/type as related to head gasket failure.

Suggests that car with head gasket replacement history may also have clogging of small passages in head and therefore should be avoided.

[632 Regal]

the M-60s go up in value again!

[Kalevera]

Gene, I think it's a bit disingenuous to interpret Mike's response as a condemnation of cars that've had a head gasket replaced. One of two things is happening with the subject of that letter: 1) the mechanic is taking the owner for a ride, or, more likely, 2) the car's a piece of junk to begin with, and the mechanic is doing damage control on a customer who won't accept reality on their lack-of-maintenance ways.

ALL US spec (and all euros, that I can think of) E34s have aluminum head(s); ALL are subject to head gasket failures, albeit some with greater frequency due to engine material composition. Head gaskets are usually a composite material, subjected to extreme pressure and temperature for long periods of time. As with any gasket (or anything else in the universe, for that matter), entropy is the ultimate result. Aluminum oxidation is hardly the single source or cause of head gasket failure. The simple fact is that antifreeze loses its anticorrosion properties over time. If it isn't changed, bad things happen. I doubt there are any E34s that don't have some oxidation, somewhere in the cooling system.

For me, the letter reinforced the necessity to use cool blue, versus anything else, and the importance of timely coolant changes. However, my primary thought when reading it was that the owner didn't care too much about maintaining the car...which we all know is a no-no.

best, whit

[Jon K]

Gene, I think it's a bit disingenuous to interpret Mike's response as a condemnation of cars that've had a head gasket replaced. One of two things is happening with the subject of that letter: 1) the mechanic is taking the owner for a ride, or, more likely, 2) the car's a piece of junk to begin with, and the mechanic is doing damage control on a customer who won't accept reality on their lack-of-maintenance ways.

ALL US spec (and all euros, that I can think of) E34s have aluminum head(s); ALL are subject to head gasket failures, albeit some with greater frequency due to engine material composition. Head gaskets are usually a composite material, subjected to extreme pressure and temperature for long periods of time. As with any gasket (or anything else in the universe, for that matter), entropy is the ultimate result. Aluminum oxidation is hardly the single source or cause of head gasket failure. The simple fact is that antifreeze loses its anticorrosion properties over time. If it isn't changed, bad things happen. I doubt there are any E34s that don't have some oxidation, somewhere in the cooling system.

For me, the letter reinforced the necessity to use cool blue, versus anything else, and the importance of timely coolant changes. However, my primary thought when reading it was that the owner didn't care too much about maintaining the car...which we all know is a no-no.

best, whit

Thats ridiculous. I guess cars that have had new radiators suffer the same issue.

So, let's see... cars that have had head gasket replacement... so what he suggests is every car with a failed waterpump or insufficient cooling system that overheated failing the gasket should be discarded... wowsers thats a lot of cars.

[t_marat]

why is everybody saying "cool blue coolant"? as far as I know coolant color has nothing to do with its chemical composition, its just painted to different colors.

The latest coolant liquids are the ones without silicone, right? I have seen one and it is of red color.
?

[Bill R.]

their specific coolants to make it easy to identify their product. And yes some coolants have no silicates at all. Bmw's stock blue coolant however chose to leave some silicates in for protection of alloys and they have no nitrites or phosphate in it which others have. I recently changed a thermostat and housing on a 1999 528 along with the expansion tank and it had the green prestone/zerex/ whoever stuff in it, i was surprised at the amount of silicates precipitation that was present.. ie. green goo.. The internal parts of the plastic housing weren't so gooey but the aluminum parts and the rubber hoses internally had a nice thick insulating layer of goo on them, about 1/16 inch thick and feeling rather slimey. This layer won't allow heat to transfer as easily and can lead to overheating. This is the reason that bmw came out with the blue coolant to help eliminate this problem. As far as colors go they run the gamut now days. Toyota factory coolant which is silicate free,nitrite free,phosphate free is red. Bright red like transmission fluid. BMW is blue, some saab and volvo are blue, Chrysler and mercedes are kind of a piss yellow. GM dexcool is orange... some of the newer volvos are kind of a bluegreen. Ford uses a green in some cars and a premium gold in others now depending on the life of the coolant. Since i do this for a living i tend to stick with what the manufacturers stuck in it to avoid the likelyhood of problems.

why is everybody saying "cool blue coolant"? as far as I know coolant color has nothing to do with its chemical composition, its just painted to different colors.

The latest coolant liquids are the ones without silicone, right? I have seen one and it is of red color.
?

[Gene in NC]

Bill R, the slime is new to me but have seen enough 2002 heads to believe corrosion and since it goes somewhere small passage exposure is logical.

See thread link for blocked radiator. If it wasn't scale, what blocked the radiator?

GALE post on flushing scale:

http://www.bimmer.info/forum/showthread.php?t=16134

[t_marat]

I was planning to put this antifreeze into the car:
http://www.geocities.com/t_marat/Val...ze_extreme.pdf

What do you think of it? Vavloline is a reputable company, but this one does not contain any silicates.

[Bill R.]

Bill R, the slime is new to me but have seen enough 2002 heads to believe corrosion and since it goes somewhere small passage exposure is logical.

See thread link for blocked radiator. If it wasn't scale, what blocked the radiator?

GALE post on flushing scale:

http://www.bimmer.info/forum/showthread.php?t=16134

[t_marat]

Have a look at this:
http://www.valvoline.com/downloads/D...e_Mag_53_g.pdf

So the Antifreeze Extreme is an OAT coolant, while BMW recommend HOAT.
What would you do?