The manual says G30 but our great and knowledgeable member Geo wrote in his pdf not to use OAT coolants as they're bad for the system. Any advice ? Thanks

 

I'll take a stab at this:

An 05 Bentley calls for G30-91 antifreeze which is an HOAT formula (not OAT). Lots of controversy when OAT (orange Dexcool) was introduced. The key to using organic acids formulas is to NOT mix different formulas. So much controversy in coolants that manufacturers have "color coded" different formulas. You should stick with the recommendation from the manufacturer. HOAT formulas are typically blue. OATs are typically orange. Here is a supplier of a G30 based formula - Zerex.
https://www.oreillyauto.com/detail/a...305050/2496989

First open the cap and visually verify the color. As cars age, and "people" make mistakes with antifreeze, your car could have a different color. If so, and you are just topping off, be advised, stick with the same color. If one is going to change formulas from the factory recommendation, it is a rule of thumb you must completely flush ALL of the coolant out of the system before recharging it with another type (color).

All this said, and BC this has become such a mess, some suppliers are coming out with a "Mixes with Anything" formula. I believe Prestone has a formula like that called Prime.

Lastly, when I first looked at my coolant in my 05, it was orange, not blue. I topped it off with water. Until I can flush my system completely, I am not chancing adding antifreeze "of a different color", to play off the Wizard of OZ.....

 

Thanks Bwings; I went and bought G13 from Audi which they said is an HOAT but is pink in color. The guy said it's approved for the Bentley so I'll take his word.

 

The manual says G30. The reservoir on my 05 CGT clearly has G12 factory stamped on it. The fluid in the reservoir is reddish. What gives? G30 usually is blue. Not implying that color is a giveaway of what's in the system but it is an indicator.

 

I'll only suggest this because coolant types and technologies are so messed up!

I would follow the G12 recommendation on the cap and ignore the conflict of the G30 in the manual. Since the color of the coolant is in line with the G12 on the cap, and the cap was obviously matched with the coolant in the system if it is the factory cap, I would use G12. It could be that the factory used different long-life coolants for different markets in those years. Perhaps North American cars were filled with G12 because G30 might not have been available in NA then.

As said, my 05 has orange coolant and not the normal blue G30 as specified in the manual. For me, the info on the cap would be the information of last resort.

 

After looking again on my 05 GT, I too found G12 stamped on the tank (not the cap). It makes sense with the color I see in the tank. G12 for me. I will be flushing soon and will replace with G12.

 

After spending WAY too much time on this to sort out what I needed to do a flush - if you have an early MY Continental Gt/FS, etc., and you want to be technically correct on coolant, first LOOK for a G12 stamp on the coolant cap or tank (mine was stamped on the tank in white ink). If you have G12 in the system then Pentofrost SF is the correct fluid. MAKE SURE it has the SF suffix and no other suffix because, of course, Pentosin also makes all the "colors of the rainbow" in different coolant formulas.

I found Pentofrost SF in a local parts store in the States; Autozone. Here is a product info sheet on it:

http://www.pentosin.net/f_antifreeze.asp

 

I finally got around to flushing and refilling cooling system with g12 anti-freeze. Access to the radiator drain valve was difficult. By removing the passenger side intercooler hose I was then able to turn it a quarter turn and nudge out.

Upon removing the intercooler hose, I discovered and was reminded of past turbo charged cars that engine oil accumulates at the bottom of the intercooler measured in ounces. There's a variety of reasons why this happens. Essentially, since modern engines are emission controled with a PCV system (Google PCV) the intercooler behaves as a condenser. When crankcase fumes are passed through the intake they condense in the intercooler and accumulate as a liquid at the bottom. The same was true on the driver side intercooler hose.

On higher-mileage turbocharged cars it's a good idea to periodically inspect that area and get the oil out. If the turbo chargers' oil seals failed there would be more symptoms than just this.

This could be a do-it-yourself project? Better to ask your service tech to check for this one.

 

Yes, agree! I recently flushed my coolant and found approx 2 oz of oil in the intercooler tube. Good advice to clean those tubes if you happen to be under the car with the front air foil cover off. Simple once you're down there. Remove two hose clamps, remove the rubber EL connect tube....watch out you don't take an oil bath!