G48 or G05 in 91 BMW???

[JHZR2]

wavinwayne-one back at you!

My 91 E30 BMW 318i needs a ew heater valve. The heat doesnt come up unless it is full hot, and at that point, I sometimes get a very slight scent of coolant. OK, whatever, the car is 16 years old, has 110k miles on it and rubber orings and whatnot get old.

So, I took it to a very good BMW only shop near me. Ive never been there before for service, but since Im new in the area, I have to try someone, and I got a VERY good feeling in talking to this guy.

Today he called me regarding my choice in coolants. He said that despite the fact that I requested the blue G-48 BMW coolant, that in my system, since the water pump components and other things were not plastic (plastic water pump impellers have been troublesome in some newer BMWs), that he has found that in the older models, one might as well save the $10 per gallon of coolant and run either G-05 or an 'all makes and models' coolant.

So... this is a chance to run G05, which is very similar to G48, in my car. He said that he has had nothing but success using non-BMW coolant in the older cars, and it is only the newer ones tht have more plastic parts where he has seen an incompatibility issue and would use G-48 only.

Should I do this? Zerex G-05 coolant instead of BMW G-48? Im always a proponent of factory fluids for ATF and coolant, but given my analysis of the spec sheet, everything is VERY close, except color. In fact, G-05 seems to protect better in some cases of corrosion.

Should I go for G-05 like he reccomends? Or stick with Blue???

Thanks!

JMH

 

[Carmudgeon]

I switched to G05 after a lifetime of G48.

The only significant difference between the two is that G05 is nitrited and G48 isn't. G05 has a touch more silicate, but otherwise, the two are almost identical -- both HOAT, non-phosphate, low-silicate, low-pH coolants.

As you've discovered, in some respects, G05 is superior to G48. Few people who adhere to the factory BMW(/Saab/Volvo) G48 mantra probably even bother to research the coolant chemistry to validate their position. Nor do they think twice about using non-OE oils and lubes, while fretting only over the coolant. Not very consistent, is it?

The best point they can make is that the cost difference is insignificant. It is, but everybody has a different price sensitivity point. I'd ask anybody who objects on that basis how willing they'd be to hand over a Hamilton, or fire up their PayPal account.

For a car that is long out of warranty, I wouldn't worry about it.

 

[BillionPa]

http://www.bimmer.info/forum/showpost.php?p=233833&postcount=20

 

[BillionPa]

I buy my G48 for $12 a gallon at the local SAAB dealership instead of $20 a gallon for the BMW logo on the bottle

 

[JHZR2]

Billion, etc. You make a point that the G-05 is acidic, and the G-48 is slightly basic. Does this matter much? This is the concentrate, and so as a result, assuming that you are diluting with Ph7 or so water (water does get acidic in air due to the absorption of carbonate from the air), the pH of that bulk fluid test becomes slightly irrelevant.

Also, during use, doesnt all coolant become acidic??? THe G-05 has a higher reserve alkalinity, such that I wonder if it matters?!?

And, in the end all, looking at the tests, it seems that the G-05 has less corrosion. The only place it doesnt do as well is in water pump corrosion, where it geta a 9 after 100 hours, instead of a 10 for the G-48. However, I know that the4 water pump is original in my 83 MB 300D (as is the radiator and hoses), and it has seen nothing but OE MB coolant, with citric acid flushes (MB - mandated PM) inbetween. Not bad to have a radiator last 23 years and 230k.

What are your thoughts??? Perhaps a weak acid with high reserve alkalinity (buffering capacity, I suppose) is better than slightly basic with less reserve alkalinity (albeit small difference), and poorer corrosion results.

I appreciate your insight!

JMH

 

[Russell]

Planning to try G-05 in my 95 525i when I change out my BMW blue. My dealer wants $25 a gallon for the blue now. I think teh G-05 is fine even though this model has a lot of plastic parts especially the radiator.The water pump may be a plastic composite. The thermostat housing was changed from factory plastic to aluminum. Just my current plan.

 

[BillionPa]

ok i got the goods:

G05 is better if you change the coolant more often
G48 provides longer corrosion resistence over time

i think...

 

[Big Jim]

Don't forget that Mercedes uses G05.

 

[Thermo1223]

I just go with G-05, It's cheap and works, and funny about plastic impellers.

Maybe that is why VW stopped using them. I know they self-destructed but never knew the real reason. Coolant perhaps?

 

[faqulars]

i have two gallons of the BMW antifreeze and after reading the back label it states that it has the 2EH that dexcool does. Does this still make it qualify as a HOAT coolant? For those that need a picture I can post one up.

 

[doitmyself]

fagulars,

MY interpretation (right or wrong) is that OAT coolants contain one or more organic acid corrosion inhibitors, some of which are benzoate, sebacate, and 2EH. They contain neither silicates or phosphates.

It becomes a "hybrid", or HOAT, when you use one or more of those organic acids WITH silicate.

This article is one of the most comprehensive I have found explaining the "confusion":

http://www.gates.com/brochure.cfm?brochure=2822&location_id=2877

 

[Tones]

My Volvo branded G48 coolant also has the 2EHA. And yes it is a HOAT.

 

[ffracer]

You can get Zerex G-48 at truck stops and for a lot less than BMW coolant or other. I think I saw it for around $8.

 

[JHZR2]

Really?!?!?!????

Under what trade name, zerex?
What truck stops?

Ive not seen this, though Im only usually looking for delvac 1.

Thanks!

JMH