Procedure for adding / checking coolant x-flow

[Tom H]

Hi folks, looking for some help on this. I have an 89 1700 x-flow with an unsealed coolant system and a coolant overflow tank.  I am trying to determine the correct procedure for checking the coolant level and adding if necessary.  I have determined I don't have an expansion tank - as it is an unsealed system. I checked it on the weekend cold and without the thermostat open there was no visible fluid under the cap.  No over heating issues - just trying to do some basic preventative maintenance. Thank you!

[jonsymons]

Hi Tom - I assume you have a catch tank just behind the rad on the nearside front with a small diameter expansion hose running to it from the thermostat housing  - and got no leaks?

I have the same system on my 1600 X flow and when I bought the car last year spend a lot of time on this forum reading posts about X Flow overheating and converting to a sealed system although a lot of those seemed to relate to cars taken on track (which mine isn't)

I gave the issue a lot of thought - the problem with an open system is that coolant is discharged when hot but as the engine cools it will draw back in air through the expansion hose  so you appear to loose coolant until the level drops to the point that the water no longer expands out - and you cant see any coolant when you open the thermostat housing.

So I tried an experiment - I brimmed the system, cleaned the thermostat cap really well (both seals) and then put a couple of inches of coolant into the catch tank so that the end of the expansion pipe was always under water. That way as the engine cools it pulls back in coolant, not air.

1500 miles later I've not had to top up the system and try not to open the thermostat housing too often to avoid breaking the seal. Before each run I tend to squeeze the radiator top hose to make sure there is water in there - you can hear the little widget in the small bypass hole rattle if there is water in there when you squeeze the hose. 

I tend to leave the heater valve open when I park the car up too to make sure the coolant all contracts evenly.

I took the car to Shelsley recently and had no overheating issues. It had a nice new ali rad just after I bought it and my bigger problem is over cooling on cold days.

Just my experience but might be worth a try before you consider any more major replumbing?

 

[Tazio]

The hose that fits into the expansion tank, the end should be cut at a 45 degree angle, and pushed so the point of the hose touches the bottom of the tank. The 45dregree cut is to ensure that when the engine cools and syphons the water back from the expansion tank water is able to be drawn back into the thermostat and top hose, whereas if you leave a straight cut across the hose, the syphon action can seal the hose to the base of the tank, preventing the water being sucked back into the system.

I'm in the process of getting my crossflow rebuilt, and will be installing a sealed system, using of all things a Dacai Duster expansion tank mounted on the scuttle as I have no heater The main hose is going to the outlet on the water pump, and the smaller hose on the tank will be connected to a connection point on the replacement thermostat housing, which comes from a later model Fiesta.

[Tom H]

Thanks to both for your comments.  I checked the hose in the overflow tank and it is indeed notched as you indicated. My question (albeit a novice one) is to what level and how to add the coolant if necessary? Do I open the tank, let the car run until the thermostat opens and then add coolant leaving a small air gap at top of the filler neck? Do I add to the overflow tank and watch to see if any is drawn back? Heater switch on or off? I have read many of the posts about a closed system and I am likely to make the switch in the future but in the interim - just looking to make sure I take care of the one I have properly.  Many thanks for your further responses.

[NS]

If it's simply an overflow / catch tank can coolant be drawn back? On my x-flow the hose running to the overflow tank is connected to the filler housing and needs the pressure cap to activate to expel excess coolant. When the pressure cap seal closes there is no way coolant can can be drawn back as the hose is then above the pressure cap's seal. Just curious if there are different arrangements without going down the sealed system route. My car is a 1995 1.6 x-flow as supplied by CC and no engine modifications or heater. 

[jonsymons]

Tom, to fill - with engine cold, just remove the pressure cap from the thermostat/filler housing and fill up to the lip (ie the ledge where the cap sits on). A couple of squeezes on the top rad hose just to expel any air and then replace the cap.

The hose in my catch tank is notched at the end too - now I know why! 

NS - assuming you have the correct pressure cap, it will allow water back in as the system cools. There is a seal on the back face of the central sprung plunger I recall so as the pressure drops that will open and syphon coolant back in (...or air if the catch tank is empty).

[Tom H]

Thank you. Seemed like a novice question I know  - but there is so much information about the closed systems - figuring out how to maintain the one I have is much appreciated.

[jonsymons]

Hi Tom - Hope my ramblings were of some little use. I'm a complete novice too having got the car in Sept so still learning from this forum (thanks to the likes of Tazio etc) and enjoying the process . Are you pleased with your X Flow? I am, if for no other reason than the noise! I found mine popped and banged a bit but I've started to use 97 octane fuel (lots of...) and balanced the carbs (which is v easy) which has made it happier. Going to tackle the timing next...

I was going to ask if you ever drove through Caledonia ON as we have family there and visited a few years back, but having looked on the map you're several hours away - hard for us small islanders to appreciate how big Canada is.