Coolant leak and empty expansion tank

[KKson]

Hi all, I know there are a number of historic posts regarding this subject but I'm a little perplexed as to what goes on when the engine gets hot and my current issue.

I've had the Wedge now for over two months and it hadn't used a drop of coolant, although the expansion overflow tank took turns trading water, but overall when all had cooled down, all was happy.

After a bit of a thrashing over the hot weekend I checked the coolant and the overflow bottle had completely overflowed and the expansion tank was completely empty. Alarm bells ringing at this point. The expansion tank had been fitted with a new 15psi cap shortly after I bought the car.

This evening I checked all fluids, and with the cap off started the engine and watched the fluid level in the expansion tank gradually creep up to the top. Why is this? Is it due to trapped air in the system expanding and expelling the coolant? There were no bubbles in the coolant, no smell of petrol or exhaust gases, just clear coolant recirculating.

Anyway put the cap back on and in a few minutes the top rad hose started leaking. Sorted that out by tightening jubilee clip even tighter. Left it a few more minutes then a new leak started at the bottom hose of the expansion tank. I've got a spare in stock so will swap out both tank and replace hose tomorrow and see what happens then.

My view however is that if it was just a leak in the expansion tank then why would the overflow bottle be completely flooded? I'm concerned that it's the head gasket which has pressurised the system and caused maybe both of the leaks? But why is the coolant clean, without bubbles and without obvious contamination?

Any thoughts? I have ordered a brand new stainless cap so will also see if that makes a difference.

http://www.ebay.co.uk/itm/151136040121?_trksid=p20...

[Supateg]

A non pressurised system will boil over quicker than a pressurised system. Once the little leaks are rectified it should be ok.
If your concerned put some coolant exhaust gas tester dye to make sure.

Craig

[jmorgan]

You have to stand back and think about the layout, mine is a lot simpler than when I first bought it but simple things like raising the expansion tank or laying the expansion pipe from the swan neck filler a different way or fitting a bleed valve for the higher 400 heater hose, all seem to help.

Edit. At Bruntingthorpe Mania one year, my fan failed so no runway runs, so, car lined up with bonnet up as per usual with the wedges and noticed the expansion tank had filled with the heat of the sun. Realised my system was not pressurised and turned out to be the swan neck sealed cap not making a good seal and was weeping air.

Edited by jmorgan on Thursday 17th April 07:18

[mrzigazaga]

Hi mate..As said if the system has a leak anywhere then it will boil...If you still have the plastic Ford expansion tank then they have inserts in the inlets/Outlets that can corrode and cause the plastic to crack or split...Be careful when over tightening.

I think the cooling system has baffled a fair amount of people..Mine doesn't flow inside the expansion tank but it doesn't boil over either...Make sure you don't fill it too much as it is "An expansion tank"..I would only put around a litre in there and probably half a litre in the catch tank below it...

Get the coolant tested with a hydro-carbon tester but make sure whoever you use for this has a good reliable one that is calibrated and cleaned regular.

Probably just air boiling the coolant but its worth checking mate...Ziga

Edited by mrzigazaga on Thursday 17th April 16:27

[ElvisWedgely]

Make sure the swan neck cap is air tight. Make sure you have the correct rating cap on the expansion reservoir and that it's a good seal. Check and test for hydro carbons in the water and that there are no leaks anywhere else. If all of these are OK then its likely go be a stubborn air lock in the system. Just a matter of trial and error, and trying out several different methods of bleeding the system.

Worst case scenario. Head gaskets, blocked water passages, cracked block or damaged core plugs or blocked radiator. However, none of these should apply if the above tests are all good.

Tony.TCB

[MethylatedSpirit]

Here's a few things you can check:

Make sure the cabin fans blows hot air.
Check operation of rad fans
Buy or borrow new expansion tank cap
Check for hydrocarbons in the coolant
Check all clips
Bleed coolant system
Pressure test coolant system when cold and then warm.


Don't know about the wedge cooling system but on the chimaera I had to put it on axle stands at the front to get the air locks out.

[KKson]

All, many thanks for advice. Replacement expansion tank all plumbed in. Will run it up to temperature later this evening so see what happens. Cheers.

[jon haines]

I have had this problem and head gasket problem and here are my differences. When the head gaskets had gone I got white foam spewing out and lots of it, you could also smell fumes in it. I have found when air or air locks are involved you get clear anti freeze spewing out but when it cools down it sucks it back in. I also have found that its worse when pottering round but when I cane it nothing spews out. So as others say try and work that out. I dont know why tvr didnt copy the rover set up for if it was designed by them it worked.

[wooly350i]

When the v8 system cools the water contracts and the stainless swan neck pipe empties until it re heats and expands again, it the rubber/ silicone elbow onto the block is higher than the pipe without even an air vent so its always gonna catch air at its high point unless you manually squeeze the pipe to get it out. The cap on the stainless pipe is actually lower than the bent hose.
We'll that's how mine is anyway.
At present everything is fine but for the antics with the gauge.

[adam quantrill]

I have seen the white foam too on a bad gasket blow, but I have a slight one on mine, from number 8 cylinder, and it just bubbles a little bit with no foam. It also pushes out and sucks back in when cold.

I know it's the problem 'cos if I disconnect the injector on no 8 the problem stops.

You can do the same - take off one injector connector at a time and see if the problem goes away. Yes it does run a bit lumpy on 7 but it doesn't do any harm.

Usually the problem will be on 1, 4, 5 or 8 because these cylinders are next to the water passages.

[The Hatter]

With TVR's plumbing the expansion tank does fill up (visible with the expansion tank cap off). This is because the plenum heater circuit outlet is plumbed into the expansion tank and the expansion tank lower connection is plumbed into the tiny connection on the top of the radiator - so the water is pumped in but can't get out fast enough.

The above means that the air in the expansion tank is pushed out of the top of the expansion tank and into the swan neck or the heater return pipe and then circulates around the engine - bonkers!

The SD1 is different, God knows why TVR didn't copy it. I wonder if TVR had loads of Ford Capri header tanks and decided to use them... and seemingly randomly connected the three outlet spouts. The SD1 tank only has one connection.

To be fair to TVR they couldn't use the SD1's viscous fan, plus the problem of rejecting heat in a fibreglass bodied car is worse than that for a steel bodied one. Maybe the plot behind including the expansion tank in the main system flow was to gain a little extra cooling?

[KKson]

Hi, just a quick update but all now seems well. Fixed all the leaks, changed a few hoses, fitted new (old stock) expansion tank with new shiny stainless 15psi cap and ran it up to temperature and left it there for an hour with the cooling fan kicking in and out. Then thrashed it around the block a few times and all is behaving.

Thanks for all the various comments. MOT next Saturday so next job is to fit my new seat belts as old ones are buggered and certainly won't pass a test.