14 replies to this topic

[Jfcrouch72]

Hi everyone,

 

I know there is a similar thread going on in regards to water leak, but I didn't want to hijack it....hence this one.

 

I've been having coolant loss for a while on my 1275 S engine...not to the extent i need to put litres of coolant back in, but I do need to put more than 'a drop' back in.

 

The engine has been checked over for head gasket (now replaced), valves all cleaned up, reseated etc...pretty much the head has been checked over and given a clean bill of health.

 

So..after about a 60mile journey, I park the car up at home in the garage....throughout the whole journey the temp fluctuates between 75-85 (perhaps just above).  I have noticed that the water temp does seem to get to @70 degress pretty quickly...but then it stays in the 75-85 range from then on.

 

When I park up...I'm not going to take the rad cap off due to heat, pressure etc.  So..I leave it overnight and come back in the morning to check it.

 

Water level has dropped...definitely below the top of the gills in the rad..I reckon I had to add about 1/2 litre in there of coolant.  I did notice puddles on the floor though...however, I can guarantee that now i have topped it up..the level will not drop if i leave it alone.

 

Would this potentially be a faulty rad cap?  Obviously, being an 1275 S A-block, there is no expansion tank.

Is there a possibility that the water can come out of the cap once the engine is turned off, but the heat is still increasing (initially, due to no airflow)?

 

any suggestions gratefully received

 

thnx.

[Ethel]

Yes to the last one. With the engine off there's no water pump operating and the water in the head can easily be boiled. Temperature gauges are rarely that accurate.Ideally it will heat up until the thermostat opens and then stay at that temperature, you can check the thermostat by heating it in a pan of water using a thermometer. Compare where the gauge plateaus with that figure.

 

You're always going to get a little water loss because the water bump has to have an axle, connecting it to its pulley, that is loose enough to turn.

[Spider]

Put a catch tank / bottle or something on the end of the overflow hose, even just as a temporary for one run, that'll quickly let you know if it's coming out that way.

 

IMO, these cars (all cars) need and should have a header or overflow tank. I always fit them, but none the less, from your description, there's something going on here. Could be the cap but ???

 

You can have the cap tested and it wouldn't be a bad idea to have that and the cooling system pressure tested, but best done when hot.

[racingbob]

i had similar with a new cap bought new cap presto fixed

[mikal]

Something is not quite right. I drove my car Melbourne to Bali (lets say 10000km give or take), souped up 1275 engine, no expansion tank. A lot of the driving was in the tropics. I checked the rad. often as you do, never had to top it up...

[Jfcrouch72]

yep..something is definitely wrong, but i'm hoping that in this case it 'might' be a simple fix.  Obviously it's loosing coolant...however, basing it on the fact of what i saw this morning i.e coolant on floor...something happened after parking up the car last night.

 

To me...at least that indicates that there was still coolant present when i got home (which is a positive).  Then the fact, that it all ended up on the floor and not in the engine/oil.

 

One other thing I observed is that the level of the oil on the dipstick had not raised.  Previously when I had an issue (and it proved to be a head gasket failure), the water got into the oil and as a result (besides it turning a milky grey colour) is that the level rose.

No such thing this time...oil is golden brown, still the same level.  Coolant level has dropped, but it seems to be on the floor.

 

One other observation which I've just remembered.  If you get a torch and shine it down the length of where the overflow pipe is (coming out of the top of the radiator), it sits just above the subframe.  It is wet down there...which also seems to indicate that something has come out over the overflow.

 

thnx.

[nicklouse]

head gaskets can go many ways. between cylinders, between cylinder and oil, between cylinder and water and between oil and water.

 

take cap off and run it. what happens.

[Jfcrouch72]

well...when i've run the engine, parked up...so just ticking over with the cap off...it just merrily sits there with the water level rising a bit..no bubbling away.  I even tried one of those block test kits which you park over the radiator filler neck and watch the colour of the magic sauce in there.

 

No change..stays blue.

[nicklouse]

ok what pressure cap is it?

 

if a 13lbs I would be then looking at rigging up an expansion tank.

 

blanking cap on rad, hose to a suitable tank and a 13lbs cap on that.

 

fill rad and half fill tank.

[Spider]

There is long and short reach (length) caps. If your radiator needs a long reach type and you've fitted a short reach, then it's relief pressure is only about 2 or 3 PSI, not the 13 as per should be.

 

If you measure the depth of the neck on the fitting of the radiator, the short reach type is 19 / 20 mm and the long reach is 25 mm.

 

This is where to measure

 

 

 

these are some of the difference reach caps (the one on the right is what is normally fitted when a header tank is fitted)

 

Edited by Moke Spider, 12 September 2016 - 07:42 PM.

[Jfcrouch72]

Update....
I put a catch bottle on end of overflow pipe today just to see if I could see anything coming out. I also put a brand new rad cap on.

I then ensured that I didn't put too much coolant in the radiator...this time it just covered the cooling fins inside.

So...off we went..did 60 miles..never overheated..it did get to 90 at one point as I was parked up for 15mins in petrol station.
Got home..switched off and left it. 3hrs later I check the water...all on the floor again and nothing in the catch bottle.

what the hell?!? The water level has dropped to exactly the same point as previously and yet if I top it up now..it won't leak. It only leaks when hot, out of somewhere and too the a certain level. I'm assuming that's because there is still pressure present, hence no leak when cold even after topping up the levels.?

Any ideas? Really frustrating.

Edited by Jfcrouch72, 14 September 2016 - 06:05 PM.

[nicklouse]

Sounds like the top tank has a failure on the join to the core.

Fill level should be about 1" above the core by the way.

I would have the rad pressure tested off the car.

[Spider]

As Nick's suggested, have the system pressure tested, it will save you a lot of agony by the sounds of it! Many garages have the gear to do it (even I have that!) and either won;t charge much for it or could even be a freeby.

 

Are you using a coolant, something with a bit of colour to it?

 

I ask, because it can help to see where it's coming from. After a run, get in there with a torch and have a look.

 

If it's not the cap - and I think we've safely established it's not, other likely candidates are the by-pass hose and water pump, but have a look at the hoses and the bottom of the radiator too.

[carbon]

I'll probably get shot down in flames for saying this, but Radweld does have its uses...

[Mini Manannán]

When I was a poor student my rad survived for a year on egg whites!