Morgan +4 Forum

Richard, I suppose you could ask Morgan Spares where theirs are made. After I repaired mine it did not suffer much more corrosion, but has warped again since there was so little metal left. BTW, I might be derided for this, but I use modern long life coolants in my old cars and tractor (all with brass and copper radiators). I've been doing this since they hit the market 30 years ago or so and I am a believer in the new formulations. I'm also lazy about changing it. Every ten years or so at best. Fred

Hi Mark,
I have the two pipe housing as I still have the original radiator header tank.
I thought the later single pipe applied only to the cowelled cars from 1955, but I can see yours is a flat-rad, so I assume you have had a new rad with a single pipe feed?
That is probably superior as regards cooling- the double pipes are very small diameter!

My problem is actually with the lower part of the housing- strangely there is not much corrosion on the top one.
This is lucky as currently this part is unavailable here!
I expect I could get one from over there but postage is usually very high!

Incidentally, my car has a Vanguard engine but with TR3 head and twin SUs, Much more power but it runs very hot, and I don't think the double pipe feed to the rad helps?
I run it without a thermostat but I am not sure that actually helps much!

Thanks for your reply and the excellent photo. Perhaps you could tell me a bit of the car' history?

Regards, Richard

Hi Fred,
I forgot to ask you what you meant by "long life coolant"? Do you mean water-less?
My researches here seem to point to the very basic ethylene glycol as being best to counter corrosion!
regards, Richard

No, Not the waterless Evans stuff. I wouldn't touch that with a ten foot pole. Poor specific heat capacity. Long life coolant mixed 50/50 from any of the major brands. I usually but not exclusively buy Prestone here in Canada. Richard if you are running without a thermostat, make sure the recirculation line back to the pump is restricted somewhat. I run a generic Chevy thermostat in mine with a 1/8" inch hole drilled in the body of the thermostat. For the recirculation line, I filled that part of the housing with JB weld and drilled a hole in it. I think the hole size was 3/16" but I can't remember exactly. I may have it written down. If your engine is overheating have a look at the end clearance of your water pump. That should be no more than about 20 thousands of an inch maximum. Fred PS can you post a picture of your two outlet top piece? I've never seen one. TX

> Long life coolant mixed 50/50 from any of the major brands.

Yes! The main thing here isn't the brand, it is don't mix your own with tap water from concentrate. Buy the pre-mixed 50/50, since factories use distilled water to keep the ion content low. Low ion content => low corrosion risk. Tap water is hit or miss.

And I stand by the zinc anode. If it's good for marine applications...

Hi Fred,
I'm still not fully au fait with the way this forum works!
I posted a reply to you some days ago but I can't see it anywhere?

Forgive my ignorance but why do you need to restrict the recirculation pipe? Is it to ensure the coolant flows through the radiator?
I left out the thermostat in the hopes of improving the cooling, but I remember you posting a while ago about reducing the end-float on the pump.
I will have to investigate that.

However, I am interested that you are running WITH a thermostat and yet you have still restricted your recirculation to a 3/16" hole?
Could i ask you to enlarge on this subject a bit please.

As to a photo, the technology beats me a bit!
I have photos on my i-phone but how to get them on to my PC, and then on to this forum, is a bit beyond me at present!!
regards, Richard

Richard, The original type thermostat had a sleeve that partially blocked the recirculation port when the thermostat opened, and partially unblocked that port when the thermostat was closed. Without that type of thermostat (bellows type with a sleeve), too much hot coolant will recirculate back to the pump suction rather that going through the radiator. Even without the thermostat in place, there will be too much recirculation flow. What I've done along with many other people is buy the simpler, more robust thermostats and simply reduce the total amount of recirculation flow by putting a restriction in the alloy hose connection leading to the pump housing. Since I was already repairing the housing with JB weld, that's what I used. Fred

Hi Fred,
Thanks for that very clear reply.
I have had the car since 1969 and that is the first time I have heard about the sleeve type thermostat!

I have now filled the outlet with J-B and drilled a 3/16 hole in it. hopefully this now solves that problem.
I have not decided whether to use a thermostat yet?
However, you mentioned a 1/8 hole in the body of yours? What is the purpose of that?

Thanks for taking the time to explain these things. I am not really an engineer so I suppose I don't tend to think like one.
It all makes sense when you explain it!

I have now managed to send my photo to my email so you may get it with this if it works!
Regards, Richard

Richard, You might be able to find a thermostat with a 'jiggle valve' in which case you wouldn't need to drill a hole in the thermostat. The hole provides some more minimum flow for the pump (in addition to the recirc line) while the thermostat is still closed and also allows any gasses to vent to the top tank of the radiator while the thermostat is closed. You don't want any gas pockets in the block or anywhere other than the top tank. The hole also makes filling and venting the system easier. Fred