Hi All,

I spent a long time looking for this and found OAT, pink, blue, silica free etc etc. I've seen on other forums all the arguing about which is the "correct" coolant. When I had this engine fitted it came with blue coolant.

I've just completed an almost full service and my MOT is soon to be booked, my next job is a coolant drop and replace. So, which is the correct coolant for a 155,000 mile 1999 plastic manifold M51 please?

Whatever is in it right now, unless you're going to flush the whole lot properly. They're not meant to mix, although I suspect mine has! It's now on OAT but for a long time there were some suspicious colour mixes going on...

The most correct anti-freeze is probably the official BMW stuff sold under a BMW part number. Dirty green-blue colour if I remember correctly and about 3 times the price of a normal good brand. But that particular car was being quite seriously tuned and the folk doing the job insisted that only the BMW jollop was up for it. My only involvement was earache from owner moans about the price!

Clive

I'll go for OAT, I don't mind flushing it through I did it on the last engine.

I've done 2 flushes of oil in a week (cheapo Wilko oil for flushing) and it's still coming out like black tar!

The OAT stuff should last for longer, think its 5 years rather than 2. Thats only helpful if it stays contained for the 5 years though.

I find the OAT stuff is easier to find leaks with as it tends to show up better.

I've never known a diesel engine that doesn't black up the oil within 100 miles of changing it.

Thanks Brian, I have bought OAT and flush. Waiting for a break in the weather now...

System flushed and Halfrauds pink OAT refilled. The crap that came out was nasty. All pink and shiny now