Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Coolant +8

Hi all I’ve just fitted an aly rad to my 97 +8 and have been doing a bit of research on coolant / antifreeze and I’m none the wiser so advice would be appreciated, do I go for ready mixed OAT ( organic ) or silicate based , concentrate with distilled water or tap water ? It just strikes me as odd that the engine is aluminium block and silicate based was recommended in one manual then a site I visited said organic for aluminium rads is best or am I just being to over cautious after spending a few quid on a new rad ?

Sounds like the perfect opportunity to go for Evan Waterless, I have a 97 Plus 8 with new alloy rad and that is what I went for.

There's a lot of mixed metals on a Mog cooling system, I personally would not use OAT & would stick to the more traditional Glycol types

I know some like Evans, but I think it's very heavily advertised wet snake oil & hugely overpriced

I use traditional IAT in my 2003 +8. I still have the factory radiator.

I also used Evans waterless coolant after fitting an ally rad five years ago, Been very happy so far👍👍

https://www.gomog.com/allmorgan/plus8coolant.html

Almost everything you could want to know regarding traditional (non waterless) coolant.

Thanks for the reply’s very helpful, waterless doesn’t seem like an option after looking at gomog so I’ve gone for distilled water and a glycol concentrate . I think I need a beer now

All this talk of antifreeze and knowing some +8’s are a bit marginal on cooling I thought I’d dig out my old notes from trying to cool tuned Minis I’ve tweaked

The best coolant is actually pure water, distilled to remove hardness & bits, this will not then contribute to corrosion & has the best heat capacity

Antifreeze (ethylene glycol) heat capacity is only 2.42 jules, water 4.20 & it’s denser than water, so when you crunch the numbers it actually carries around 37% less heat per volume than water

So for simplicity if we call water 1.0, then a 25% antifreeze mix will have a heat capacity of 0.91 and a 50% mix just 0.82

As you can see the less antifreeze, the better the ability of the water to move heat from the engine to the radiator, BUT of course you need some corrosion protection & resistance to winter freezing so we use antifreeze, but it’s not good practice to use too much just to be safe

As an aside to this the various ‘waterless’ coolants blend of magic additives is mainly…taadaa!.. ethylene glycol.., you pay’s your money & take your choice, but remember it WILL reduce vital heat transfer

Yesterday I jury rigged a flexible pipe totry getting extra air to the rad. The number plate box extends back well past the bottom of the rad and about 10-15% of the rad is shielded from the grill airflow. I went for a run and it does have an effect, though small. The gauge showed about 2 deg lower until traffic slowed things down. Worth investigating more though so will put a second one on and do some better tests. It looks a bit odd at the moment with the rough cut flexi hose visible by the side of the number plate. It is an attempt to duplicate the scoop style air box intake that can replace the original.

Can recommend one of these inexpensive Refractometers. Once calibrated with pure water they will measure a sample droplet against a scale of freezing point or SG of battery electrolyte to give charge condition.

Most useful I find to see what frost protection you have from coolant.