Does anyone know of the best antifreeze to use with a VHDP?
Can anyone help me out here?? Not sure if I should use pink green blue purple? It was running on green but I’ve heard that the pink could be a longer life antifreeze but I’m not sure if it would be ok for the seals or head. Whats everyone else using or been recommended?
I’m no expert but there is plenty of advice on the web. What follows is based on information published by the FBHVC and what I know…
S1 VHPD cars werew supplied filled with ‘yellow/green’ anti-freeze. A label on the expansion tank should tell you what coolant was used. There are basically 3 main types of coolant (different types should not be mixed):
“IAT” (Inorganic Acid Technology) is the traditional (older style) [color:#009900]“green”[/color] formula antifreeze that contains phosphate and silicates. This provides good protection for cast iron and aluminum engine parts, as well as copper/brass radiators in older vehicles and aluminum radiators in newer vehicles. The silicates in IAT coolants even lube rubber hoses. The corrosion-fighting chemicals are fast-acting but wear out after two to three years or 36,000 miles of average use.
“OAT” (Organic Acid Technology) is usually dyed [color:#FF9900]orange[/color] or [color:#CC66CC]pink[/color] to distinguish it from other types of antifreeze. The OAT corrosion inhibitors are slower acting and provide protection over a longer period of time. OAT coolants typically have a service life of up to five years or 150,000 miles. Though OAT provides good protection for aluminum, it may not be the best choice for older vehicles with copper/brass radiators because of the lead-based solder used in the radiator. Some say OAT-based coolants may also provide little protection against cavitation erosion in water pumps with aluminum housings (unless the pump impeller is carefully designed to minimize cavitation).
“HOAT” (Hybrid Organic Acid Technology) antifreeze is usually dyed [color:#FFFF00]yellow[/color] but may also be dyed [color:#FF6600]orange[/color] or [color:#33CC00]green[/color]. The additive package in a HOAT formula coolant contains organic acid corrosion inhibitors (OAT) plus silicates for added aluminum protection. Most of the antifreezes in this category also meet the European “G-O5” specification for hybrid extended life coolant. The service life for HOAT is also five years or 150,000 miles.
From mid. 2002, Rover/Lotus changed from the older IAT to OAT Coolant. Most older non-OAT cars will be now have been fully bled and replaced with a HOAT coolant.
Colour is not an infallible guide to coolant type as some manufacturers don’t follow the rules!; and indeed the older S1 yellow/green coolant (non-OAT) is Unipart super plus 2 (or if not available, use an ethylene glycol based antifreeze that meets specification BS 6580 and BS 5117); and the newer S2 green coolant (OAT) is Unipart super plus 4.
The different coolants should not be mixed. Arguments abound on just how bad mixing coolants really is (some anecdotal evidence of a precipitation (sludge), although it’s not conclusive), but the advice is that it reduces the benefits at least - so just don’t mix them. To swap from ony type to another, fully flush the old coolant out first. For small topping up you can use plain water, but if you live in a hard water area, distilled, de-ionised or filtered rain water should be used.
The simple answer = OAT as there is some uncertainty about HOAT technology and the little rubber bits…
Fantastic answer, I think you’ve covered just about everything there. A complete flush and then OAT antifreeze. Thank you very much. 
just to comment on mixing anti freeze types. I have a car in where this was done and the whole cooling system has turned to a silicon gel that can not be disolved, so its an engine rebuild.
hmm so now what do I do? 
Provided the sytem is flushed properly there will not be an issue. Why not get your dealer to do it and then if it goes wrong…
Seriously, there are isues but why not match what is already in there - they all work well enough. What colour is it and what does it say on the last service bill? It should be possible to work it out. If you haven’t got he bill check the stamp in the service record, call them and ask them.
Last service bill? I’m still waiting to get the first! The work on this car has been on going for the last four years. Lets just say this isn’t exactly “Rapid Fit”.
I’m just being fussy as usual, I’d be interested to see what Dave Andrews thinks if he’s about.
I see your point though, as long as the systems well flushed there all good.
Dave�s opinion would definitely be best, in my experience always keep to what�s in there, and if this is unknown a thorough flushing of the complete cooling system including heater and the return to the manufactures original specs. I have heard horror stories of the wrong type of coolant attacking seals on 1558 twin cams but I have never experienced it myself.
I had a problem once with my 1.7 combo van (ok you can stop laughing now). I changed to orange coolant after a big flush and with in 30 seconds the water pump leaked.
I’ve had this with oil as well, I changed the oil and a seal on the vacuum pump went within seconds of starting the vehicle.