Series 3 Losing Coolant after driving........

[jfjharry]

The car starts and runs great but after a drive I'm losing at least two litres of coolant. The car does not have an overflow reservoir does this mean it should not lose any coolant? In this case does this mean I may have an head gasket leak etc. Any experience in this field will help.

I have now added a temporary coolant catcher container but when cooling down it is not drawn back into the motor.

After doing more research I would like to add the following to make my situation clearer; I filled up the header tank as per the manual to the top of the lower lip of the filling neck i.e. there is no room for expansion. I have now read where some fill the header tank up to only half way. What is the correct level? The coolant bottle I fitted is at least 6 inches below the header tank. Maybe this is too low to cause reasonable suction back?
On going for a drive my temperature gauge slowly goes up, on reaching the N in normal the fans cut in and the gauge does not not go above the O in normal.

[MarekH]

Dear Harry,

I'm sure the exact level will very from car to car, but if it keeps settling at half way up the tank then I'd say that is perfectly normal behaviour.

I'd bet that if you then go through the same procedure again, no more coolant is expelled when you stop the car once it has settled at half way, because, pressure wise, that's its equilibrium level.

You may wish to check the cap for its pressure rating.

kind regards
Marek

[PeterCrespin]

After doing more research I would like to add the following to make my situation clearer; I filled up the header tank as per the manual to the top of the lower lip of the filling neck i.e. there no room for expansion.

Where does it say that? Can you give the page and quote the paragraph?

If you wish to stop coolant being ejected, stop over-filling. Marek is quite right.

[jfjharry]

Thanks Peter & Marek
In the Jaguar Series 3 V12 Repair Operation Manual under Cooling Systems under Coolant drain and refill 26.10.01 under refilling it says ----
Step 5 Fill cooling system to the bottom of header tank filler neck.
Step 6 Refit header tank cap.
I have now gone for a long drive starting with the header tank half way and still lost coolant out the cap to the external tank. There is very little left in the header tank - surely this would be unusual. Once again the temperature of the car from the gauge was the same [on the N of normal].
I have noticed a slight rattle from the front of the motor I thought it may have been from the alternator but have now proved its not from that as I removed the belts, the noise may be coming from the water pump?
The cap is a 13lb cap and appears to be in good condition but I will try to get another one just to eliminate that.
Merry Christmas to you both and thanks for your help.

[SESH]

Harry, don't discount the rattle coming from the alternator. I had a similar rattle/knocking coming from the front of the engine and it was the alternator mounting bracket. The sleeves that the alternator is attached to had worn and the alternator was moving on its mount. That could still happen with the belts removed as the movement of the engine will cause the alternator to move whether belts are attached or not. Not saying your problem is not the water pump but the alternator could still be the problem.
Mike

[vee12eman]

Hi Harry,

I don't claim to be an expert, but agree the loss of coolant in your case seems rather high.I have no overflow bottle on my Series 3 and have more fluid than you describe in my header tank.

It is possible you are losing fluid from the system at the water pump or even elsewhere. Coolant normally leaves traces to show where it is leaking from. In the case of the V12 engine this can be difficult to detect with over 20 hoses in the system. I had a leak from several hoses caused by the poor quality of the Kevlar hoses I fitted. I have replaced the whole set with a quality Cotton reinforced set from SNG Barratt.

If the coolant is indeed escaping from the overflow, then this will be encouraged by a weak radiator cap or damaged seal.

I will check my level later today - this is in a car which has recently been driving in hot days. I am fairly confident I will not find the level as low as you describe, but I will report back. Apart from filling the system when the hoses were changed, I have not had to add any fluid to my car since initial fill. This was even the case when the Kevlar hoses were leaking, since they were only weeping and I had tell-tale drips under the car after a run, tightening the hose clips solved the problem temporarily, but it came back pretty quickly.

Regards,

Simon.