Major disaster averted

[jonbarrett]

Re my other post 'Puff of steam'. Just because there is water in the expansion tank and it fills as the engine warms does not mean there is much water in the colling system. I just put three 2-lit bottles of water in and I think it will probably want more when I get all the air out!

How much water does the cooling system take?

[Allandwf]

Remember to vent the two radiator taps with the engine running, once the thermostat opens, but close before the system gets up to temperature and pressurises or it will just boil out through them.

[FarmyardPants]

Have you looked underneath the car?

Seriously though, what has the temp gauge been showing?

[jonbarrett]

I've done 6,000 miles with no running problems and no water added, including a fast run to Le Mans and track days.

It's parked in a dry garage with no signs of a water leak.

At motorway speeds the gaugue sits at about 80. At idle it hovers between 90 and 100. Sometimes it pings up and down. From other posts this seems about right.

The only reason I double checked this time was a puff of steam from the expansion tank cap when I lifted the bonnet.

Six litres plus is rather worrying but I guess it proves the engine and cooling system is pretty tough!

I'll do the air vents tomorrow.

Infrared thermometer is now showing much more even temperatures on the cooling system pipes etc.

[HarryW]

jonbarrett said:

.....
Six litres plus is rather worrying but I guess it proves the engine and cooling system is pretty tough!

.......

Infrared thermometer is now showing much more even temperatures on the cooling system pipes etc.

I would suggest its leaked out fairly recently as I can;t see it running for too long with effectively very little water in it as I think it takes about 8 or 10 litres (tbc) .

[Old Geezer]

Jon

The copy of the owners manual I have (PDF down loaded from here somewhere) says 12 litres in the cooling system. But it is a 4.2 manual.

[Allandwf]

Mine ran for at least 4 months like that before I decided to top it up to where the book said, took 4 litres ! I think even when low there always looks like there is a bit in the bottom of the expansion tank. So pays to check carefuly.

[jonbarrett]

Definitely no obvious water leak. In fact the water level in the expansion tank is how I found when I bought the car over a year ago. I use the car every days and I have only noticed the occasional puff of steam over the last couple of weeks.

I have a feeling the cooling system was low on water when I bought the car. Over the months the level has dropped slightly until it started steaming.

I'll see how she behaves over the next few weeks.

[kojak]

I always check oil and water everytime I go in mine to be on the safe side.

[southendpier]

check the oil, if you are loosing water and you can't find it you may have a manifold issue.

I think.

Now I'm no good with engines but I had a Vauxhall 3.0V6 24v go bang because of this. IIRC it was a while ago. Even the main dealers didn;t know what the problem was...the main dealer hahahah, never bloody checked did they! Never buying another vauxhall.

[amazon]

kojak said:

I always check oil and water everytime I go in mine to be on the safe side.

Me too

[jonbarrett]

Armed with my new thermometer, the water rails are 100oC and radiator core is 85oC when the fans kick in. Not sure if that is good or bad.

[DonnyMac]

amazon said:

kojak said:

I always check oil and water everytime I go in mine to be on the safe side.

Me too

...and me.

safe Vs sorry

[Jasper Gilder]

I had two 4.5 Cerbs - did about 95000 over the two - both had an appetite for water, one did have a new rad I recall - only leaked a little when hot. I came to the conclusion that they use water so topped up every couple of weeks and never had a problem.

[DonnyMac]

Jasper Gilder said:

I had two 4.5 Cerbs - did about 95000 over the two - both had an appetite for water, one did have a new rad I recall - only leaked a little when hot. I came to the conclusion that they use water so topped up every couple of weeks and never had a problem.

Mine didn't, then did, experiencing the same as one of yours, a tiny leak only when cold which was a bit flummoxing.

Took it down to Andy at APM - Bingo.

Pinprick hole, only opened up after the car had cooled, so never a leak when you were driving, parked up (after a drive) or on the way home; only after you've left it for hours and check the next day scratching your head as you've seen no water on the drive.

New rad, hasn't needed a drip of water since - still check daily out of habit/safety.

[jonbarrett]

Managed to squeeze six litres in. Bled air from radiator and water rails. Now running with full coolant for two days. No fluid loss and seems to be running smoother when hot but it might be my imagination.

[Allandwf]

Glad you got it sorted before anything untoward happened. It may help other owners to check carefuly as there looks like there's water in the expansion bottle, but the system can be seriously low. Mine has been ok for the last two months, like yours , it was low when I bought it.

[jonbarrett]

The real problem is that there is a marker on the expansion bottle showing the max level but it is hidden by the engine cover. It shows the water should reach the moulding line about 20mm below the opening.

[Jasper Gilder]

I used to stick me finger in the 'ole ( on the coolant tank) If finger comes out dry - add water, if finger comes out wet - OK - If finger comes out scalded make mental note to check when engine is cold!