Cooling system

[napa 1]

Hi all. Got those last few issues I posted about worked out. Now I'm left with, a speedometer that doesn't move, although odometer turns fine. Also, need a little assistance with the way a series II expansion tank works. It is a stock series ii set up The car runs great, I can run it for some time and it stays in operating temp, but I get water out of the oveflow valve hose whenever water is in the expansion tank. I filled the whole system up from empty, just a few days ago, so not sure if everything is circulating properly. Heater is n hot and blows hot.

1. Is it common for the little overflow valves to fail? And if so can they be blocked off and just rely on the radiator cap for pressure relief

2. What should it look like when I fill up the system and let it run with the cap off? How does this tank thingy operate? There is a jet of water from the high hose side.

3. Compression is great, no oil in water, no water in oil no foaming or bubbling coming from the filler neck etc.


Thanks for any assistance.

 

[alpine_64]

John,

Do you have the header tank with the thermostat in the header tank, (its a casting with angular edges) or the one with rounded edges and the overflow directly off the neck of the radiator cap?

The systems are low pressure and the early cars have a habit of spitting water if over filled.. the later style ones with angular casting have more of an issue than the early rounded style.. and it is advisable to run a return system on them

 

[napa 1]

It's the angular one. Yes, the spitting does eventually stop, so i was wondering if I'm just overtopping it. What should the level in the tank look like when cold? How is a return set up configured?

 

[Bill Blue]

John some of the early Series cars use a deep radiator cap. Use the wrong cap and there is no pressure.

Bill

 

[napa 1]

yes, i'm wondering if i have the wrong radiator cap. I got it from Victoria British, so knowing them it's probably from a Skoda or something.

 

[alpine_64]

John,

The radiator cap was another think i was going to ask you about.. getting the correct low pressure one with the right neck length can be quite tricky.. i'd be asking rick or carl what they have in stock.

That said... the early cars have a habit of burping a bit of coolant when they get stuck at the end of a lot of heavy traffic (the system is very low pressure and for some reason it seems to be more prevalent on early cars than the S3 onward)

if you want to set up a return system (and i would recommend it) you need to find a return cap.. early XJ6 jags have caps that can be used, you need to setup a bottle ( a rootes washer bottle would look correct in there) and cut a larger hole in the top to take a grommet and the overflow hose, the hose from the filler neck then goes into that. when it spits some water under pressure it goes int ot he bottle.. when ti cools the vacuum draws it back and the cap allows it back in.

 

[65beam]

cooling

series 2 cars with the brass pressure release valve on the right side of the header tank did not use a regular radiator cap. they had a cap similar to the oil filler cap on series 4 and 5 cars that sealed the fill neck. the brass valve is actually the pressure release valve and was set to hold seven lbs of pressure. i have one of the original caps but since it's 50 years old i use a radiator cap to seal the filler neck. with the way the releif valve works you could not recover the coolant back to the radiator if you did set up a recovery tank. the valve opens to allow coolant to exit and then closes. you might call it an upside down radiator cap. coolant expands when hot so it's like having a bucket that holds five gallons. it won't hold 5.2 gallons. it runs over. i never fill the header tank on the harringtons. i leave it about an inch from the top of the tank. i also do this on the alpines and hardly ever lose any coolant out the overflow tube. if john has this type of tank he may have a valve that is sticking open at times. i cleaned one of mine by spraying carb cleaner thru the tube coming off the side of the valve.

 

[napa 1]

I have a feeling that my valve is stuck open because it just allows what ever coolant is in the tank to flow out the hose, even when the car is just warming up. I'll try to free it up somehow. Otherwise if it's permanently stuck open, what if I plugged it and used a 7 lb long neck radiator cap, which I have, in the filler neck instead.

 

[alpine_64]

John,

Would you consider going to the early style header tank as used on SI and early SII? That way you can avoid the issue and run a return system... not sure how much driving you do around town, but I know without electric fans if you get stuck in bumper to bumper on a warm day its nice to know the coolant is not going anywhere.

 

[65beam]

cooling

john,
with an open vent you could not hold pressure on the system. if the relief valve is staying open you could find one of the early tanks without the valve or you could block it off with a plate between the tank and the valve and solder a tube to the fill neck on your tank. my fastbacks have a bottle mounted to the right of the radiator that is called an expansion tank to catch the coolant but it doesn't allow the coolant to return to the radiator. i guess chrysler did this in 1968 to keep the coolant from dumping on the ground. i should have several of the series 1 tanks in the parts building.

 

[65beam]

cooling

michael,
i think you'll find the tube on the filler neck is above the area where the cap seals against the tank. without the cap valve being open the coolant could not return to the radiator. it's another one way valve.

 

[napa 1]

Yep. That must be the issue. First I'll play around to see if I can UN stuck the valve, and then plan b will be to find a replacement tank - either the early series without the pressure relief valve, or a better later style with a valve that works.
Or, seems a simple solution would be to block the relief valve and add an overflow pipe to the filler neck and use the right pressure radiator cap.

 

[napa 1]

This is great guys. really appreciate all the help. What are your thoughts on the speedo issue. Odometer turns correctly, speedo stays at zero.

 

[Tom H]

John, something is amiss inside the speedo. Since the odometer moves, then the inside shaft is turning . Most likely the needle, or the "cup" it is connected to is stuck. Gonna have to take it apart.

See this article for some help:

http://home.comcast.net/~rhodes/speedo.pdf

Tom

 

[napa 1]

Thanks Tom. I'll take it apart tonight and see if the needle is stuck. Thanks for the link to the article.

 

[Alpine 1789]

Before you take it apart, my speedo frequently sticks when the car has been sitting for a while. I can almost always unstick it by tapping on the glass while driving. Gentle taps usually work, but I have had to rap it pretty hard before, too. Not hard enough to break it of course.

 

[napa 1]

Thanks Jim, I'll do that first, I also thought I'd disconnect and reconnect the cable in the back and move it around a bit...

 

[65beam]

cooling

i had a similar problem a couple years ago. the speedometer was also making funny sounds and would sometimes stick at different speeds. tiger tom took it apart and found the lubricant had solidified and was causing the problem. a good cleaning and lube and it works fine.

 

[napa 1]

Great ideas from all. Thanks for the support.