Mk 11 Radiator coolant level when cold

Am I right in assuming that when cold the coolant level in the top of the Radiator is quite low and and that the top of the rad is an expansion tank . Stupidly I always add coolant before a long trip thinking the coolant level is too low .
Checking the antifreeze today it was not possible to get any fluid to check it without adding some . No leaks are evident .

Kim R.

61 jag Mk 11
05 XJ8L
012 XK convertible

When I got my MK2 on the road a few years back , when I come home from the first test ride , there was a wet patch under the rad , on the ground , coolant was coming out the overflow , before the test run I did top up the rad , so you can see water , I put it down to expansion , now I have the over flow pipe going to a bottle , so I can keep a eye on what is coming out !
I do have a Alloy rad !!

Yes Kim, I have the same experience. If you fill it up, it spills over when getting warm, if you just let it be (not full) it is totally happy. I added spill overflow bottle to mine (for situations I just fill it up even I know I shouldn’t) it has been working fine. See my page at:
http://www.elisanet.fi/kopik/jag/restor14.htm
Köpi

Hi Kim, mine has the original style radiator that may have been recored. It is reliable with coolant and the level always sits (visible) at the bottom of the horizontal filler tube - it finds this level once the car has heated and pumped out the expansion excess through the cap drain tube. Paul

Paul,
Went and bought a used metal expansion tank from an MGB and put it in the left front fender . Expelled coolant when hot is contained as you know . But will it suck the coolant back from the container if needed , have a tube to the bottom of the container . Hoping I have it right . This system was used in our 79 MGB LE which has since been sold .
All this started when I went to check the antifreeze and had to add coolant to get a reading as previosly mentioned . Car is in peak running order and no coolant in oil . Coolant level falls below horizontal pipe to a degree.
This worried me as our 63 Healey 3000 just sold always had visible coolant in the rad and used very little . The rad has been recored.

Kim.

 Breen60 Paul Breen 
  November 20  

Hi Kim, mine has the original style radiator that may have been recored. It is reliable with coolant and the level always sits (visible) at the bottom of the horizontal filler tube - it finds this level once the car has heated and pumped out the expansion excess through the cap drain tube. Paul

For those that might be adding a R&P steering system to their cars and removing the bulky generator here is an idea. I kept the old generator driven power steering pump reservoir which is mounted on the fender well. I converted it to a radiator overflow so I add fluid to it when needed and it acts as an expansion tank. I had to add a special fitting and hose as I recall which was relatively easy. These radiators usually seek their own natural level and I am still using my original re-cored radiator. Expect a few drips and drizzles here and there as the cats do mark their territory. .

Gerard

As the overflow pipe of Mk2 radiator begins from ABOVE of the pressure valve, I can not understand how it could suck back the overflow. The valve is open only when there is enough pressure inside the radiator and I doubt atmosphere pressure would be bigger than that to push coolant back!
So I call mine a spill over container, one way only.
Köpi

I used a small plastic drinks bottle , made a hole in the cap for the pipe , and made a hole at the top for a overflow pipe , made a wire clip to hold it in place !

Last week I had my mechanic replace all the radiator hoses for me. When he filled the radiator with coolant, I saw he filled it to the very top where the cap attaches. I didn’t want to annoy him by telling him that I learned years ago if you fill the radiator to the very top it will shoot coolant out of the overflow tube once the engine reaches operating temperature. So he closed the cap & had me start the engine , as we waited for it to reach operating temperature. With the engine running, he raised the car on the lift to make sure the oil plug & filter housing were not leaking, as he’d just done an oil change as well. Sure enough, after a few minutes, coolant began to come down the front crossmember of the car. He said “uh-oh” but I just laughed. I told him to bring the car down and he will see the leaking coolant was coming out of the overflow tube as a result of overfilling the radiator. Sure enough, I was correct… He thanked me for being there and watching, saving us both unnecessary grief. Now he knows never to overfill again…