Volvo Owners Club Forum - View Single Post

Laird Scooby · Jun 21st, 2018, 14:02

He's "cherry picking" facts there.

Yes Volvo have changed to the new OAT coolant for cars produced from about 2000 on, yours wasn't.
Also most engines used from 2000 or thereabouts are the aluminium engines - "white blocks" not to mention in the S/V40, some are Mitsubishi engines which would almost certainly call for OAT as it was the Japanese that developed it to minimise corrosion to aluminium engines.

Your engine block hasn't miraculously changed from cast iron to aluminium so is still a mixed metal engine. If the head gasket design hasn't changed then it would still potentially be susceptible to attaack from the OAT coolant and Volvo would probably only use ethylene glycol (green or blue usually) coolant.

I see you're in Southampton, why not give Rudds a call (i assume they're still trading?) and ask their service department for the antifreeze recommendation on whatever year 940 you have and if they start suggesting the OAT stuff, ask them if that will cause problems with any gaskets.

Another thing to bear in mind is that it may have had a head gasket replaced at some point in the past and a non-genuine Volvo gasket used. As such, a generalisation about the head gasket can't be made although if it was, arguably the gasket was designed before the advent of OAT coolant and therefore may be damaged by it.

Did he actually confirm whether it was OAT or Ethylene Glycol or just side-step the question?

Jun 21st, 2018, 14:02	#34
Laird Scooby Premier Member Last Online: Today 14:04 Join Date: May 2012 Location: Lakenheath	He's "cherry picking" facts there. Yes Volvo have changed to the new OAT coolant for cars produced from about 2000 on, yours wasn't. Also most engines used from 2000 or thereabouts are the aluminium engines - "white blocks" not to mention in the S/V40, some are Mitsubishi engines which would almost certainly call for OAT as it was the Japanese that developed it to minimise corrosion to aluminium engines. Your engine block hasn't miraculously changed from cast iron to aluminium so is still a mixed metal engine. If the head gasket design hasn't changed then it would still potentially be susceptible to attaack from the OAT coolant and Volvo would probably only use ethylene glycol (green or blue usually) coolant. I see you're in Southampton, why not give Rudds a call (i assume they're still trading?) and ask their service department for the antifreeze recommendation on whatever year 940 you have and if they start suggesting the OAT stuff, ask them if that will cause problems with any gaskets. Another thing to bear in mind is that it may have had a head gasket replaced at some point in the past and a non-genuine Volvo gasket used. As such, a generalisation about the head gasket can't be made although if it was, arguably the gasket was designed before the advent of OAT coolant and therefore may be damaged by it. Did he actually confirm whether it was OAT or Ethylene Glycol or just side-step the question? __________________ Cheers Dave Next Door to Top-Gun with a Honda CR-V & S Type Jag Volvo gone but not forgotten........