Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Coolant Volume

I assume the cap shown in the photos of my Roadster setup are simply a different type of cap with a screw fixing instead of the "old" tab fittings. Or maybe not??

Bob, yes the cap shown simply 'blows off' if the pressure is too high / the header tank is overfilled (when I say blows off, it vents via an internal hole inside the cap & leaks out around the perimeter)

A Motorcraft (aka Ford) 95bb-8100-aa is a sealing cap. namely a complete block that seals an entry. I would jump at saying that this Ford cyclone engine has a recovery system, save that today's cooing systems can be Machiavellian.

I shall do some research. I enjoy it. .....I did, other Fords use a recovery system. It can cause problems but if you have none, no need to address it and non-issue. IMHO, today's manufacturers are in a never ending search to find ever cheaper ways of getting to a goal. I am pleased that your tank shows no sign of that. It is a proper tank. Bravo. the 3.7s have cooling issues, but that tank is excellent.

BTW, for the last 12 years, I have been using a simple tweak that costlessly improves all Morgan trad cooling systems, merely using utilizing a bit of history and common sense and mitigating a bad MMC habit. I combined an idea of Peter Mulberry which he used to become his performance rad for the 3.7 Roadsters. However, I mount it in a different way than the MMC and Morgan community do, though the MMC did much better mounting the later plastic trad rads and the non-trad rads like the Aeros. The first was an effort to drastically lower costs and the second was likely the influence of BMW.

Watch this space.

gmg

P.S. In my research, I ran across a very cogent (they rarely are) article on such things. https://www.enginelabs.com/engine-t...and-recovery-tanks-arent-just-for-looks/ Here is an

This is the 3.0 litre V6 Duratec based engine that has been used in a wide variety of cars including the Ford Mondeo ST220 in Europe and the Ford Escape, Mercury Mariner and Mazda Tribute in the USA.

I don't think this is a pure sealing cap as it has a "blow off" mechanism inside and appears to be set at 1.2 bar. It looks the same as the Ford OEM cap judging from what I've seen in the Ford Escape workshop manual.

It runs with a Sifab radiator and has never had a cooling problem although it can run slightly hotter at times which I think is down to the cooling coefficient of the Evans Waterless coolant it uses but that is a different conversation. (It had Evans Waterless in when I bought the car)

I am impressed with the quality of the tank on your Roadster IvorMog/Bob, I also like that it has a window incorporated to allow monitoring of the coolant lever within the tank.

GoMoG, thanks for the link to the article though as ever seems to be the way, the use of different terms seems to have the possibility to confuse...? Another example of being separated by a common language..? (-:

The base of my limited understanding is that in the case of a Morgan (and other vehicles) is that the requirement for a remote tank, would seem to be down to the lack of room to simply fit a large enough radiator, on which there might be space enough for it`s in-built top tank to contain enough air space for the required amount of expansion of the coolant as the engine rises to normal operating temperature.

In times past before aerodynamics became a primary consideration requiring ever lower bonnet lines, there was room for adequate in-built top tanks on radiators.

Back in time it was the norm was to ensure that the water level in the rad was such that it was not filled to the top, but to a level just above the top of the cores visible through the filler cap, thus ensuring adequate airspace was left within the rad for coolant expansion...?

If one overfilled the rad, then as the engine temperature rose up to normal operating temperature, the expanding coolant would lift the seal in the (two way) rad cap, and blow off the excess down the overflow/vent tube fitted in the neck of the rad.

As the coolant cooled/contracted, the secondary valve in the rad cap would be sucked opened, which would then allow air to be sucked back through the same rad filler neck mounted overflow tube, which had previously provided an escape route for excess coolant..?

The result being that the combination of a normally closed dual valve pressure cap, and a rad with an overflow tube vented to atmosphere, would arrive at creating the systems normal operational water level, from a situation of being over filled.. while avoiding creating vacuum in the system enough to collapse flexible radiator hoses..? The overflow tube normally routed down the side of the rad the end pointing down onto the road surface in a bid to expel the mix of steam and water as safely as possible.

I think I understand the design and operational requirement of a remote expansion tank, though admit to not fully understanding the purpose of a recovery tank... I suspect this terminology may confuse more than just me, perhaps causing some to think that both tanks perform the same purpose...?

It would seem that an expansion tank is just an extension of the radiator, and only required in the system due to the lack of space for a radiator with an adequately sized in-built top tank..? That being the case, the expansion tank and all it`s pipework are exposed to whatever pressures might build up within the rad....With that in mind whatever tubes might be fitted to determine the level of the coolant within an after-market tank, would seem best to be proven to handle a higher pressure than that at which the pressure cap is rated at...? A mix of steam and water escaping under pressure can cause serious burns or worse..

I would be more than happy if someone here might explain the idea behind a recovery tank as different from an expansion tank.... Or is this just another example of fake news...? (-:

Thanks for the comment about the expansion tank. It is a Williams Motorsport tank and I think it is a rather elegant solution.

I too get confused by the difference between an expansion tank and a recovery tank. My system appears to be an expansion tank and I don't know how a recovery tank would fit into the system, or indeed why one would need one.

BTW, I was somewhat confused by the cooling system when I first got the car and Dave W (Thanks Dave) kindly provided this schematic which whilst based on his Series 1 car is virtually identical to my Series 2 car.

It clearly shows the water flow and how the expansion tank fits into the system. My system is filled via the expansion tank.

I'd love to see a schematic for the CX PlusFour..... I'll bet it is a lot more complex...

Peter

Re-post of one I made some time ago.


I would add that I have never had any issue with long term leaks other than some very minor ones from new on heater hoses. I don't regard loose clamps however slight as indicative of coolant design problem on any particular model. Ditto for the OE plastic side tank rads used across the full classic range in recent times. I will admit to taking a week or two to fully seal hose connections on replacement ally rad when the OE one failed on my car, as with so many others. Finally cured by doubling up clamps on the silicon bottom hose extension required. However I haven't needed to top up since, well over a year and 7000 miles ago, despite a recent rolling road session where the coolant peaked at 106°C (normally 96 - 98°C) due to lack of adequate rad airflow.

I am not aware of any issues unique to the OE 3.7 Roadsters cooling system but happy to be corrected by other owners of this model. The larger aluminium replacement radiator was a seamless replacement in terms of warm up times and temperature indications. Cooling fan aside which rarely needs to run now. This cannot be said of some 4 cylinder models I understand where the extra cooling from ally rad can actually cause overheating on fast motorway runs due to thermostat delay in opening. The cure being lower temp thermostat.

IvorMog, I did think that your expansion tank looked a tad too "elegant" to be a standard Morgan fitment... (-:

Thanks also for posting DaveW`s layout drawing of the Roadster`s cooling system, though I note yet another term for the remote tank has crept in....When the term header tank is used in a discussion I automatically think central heating....(-:

Also from DaveW`s diagram I noted... heat exchanger... What is that items purpose in the car...?

Happy to wait patiently with fingers crossed or any feedback on the description of recovery tank design and operation in an automotive situation.