Oh @!££@!@@£! broken down again

[page3]

Some of you might remember this post back in June:

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Well, the car was fixed (faulty fan sensor) and has been running fine, although not used too much recently. Probably only 100 miles or so but including heavy traffic etc.

Today I decided to go and watch the TVR racing at Silverstone. So, M40 about 50 miles. Car running slightly hotter than I'm used to (I'm sure it used to do 70 deg when moving at speed), but steady on about 80 deg. Come off slip road in a cloud of steam as it spat a couple of litres out of the expansion tank and radiator cap

This time I had very slightly more warning, and the temperature didn't go straight to max like before. Also only 2 litres or so was expelled.

Recovery say they suspect a head gasket failure (water bubbling from radiator..) but also that the water pump is noisy.

Both head gaskets were replaced in October 2007. Since then I've probably done 2000 miles just fine, before the continental breakdown.

I so hope it is only a water pump because if it is a head gasket the Wife will no doubt insist on the car being sold

Hope the TVR's at Silverstone did better!

Depressed S owner who's lost a bit of TVR faith...

Edited by page3 on Sunday 10th August 16:31

[mikee boy]

Good luck.

Any oil in the water or vice versa?

[page3]

mikee boy said:

Good luck.

Any oil in the water or vice versa?

Thanks

Re. oil - no, all looked clear to me.

Car was pressure checked a few weeks ago (along with checking hoses, cap, fuses, etc etc) when the faulty temperature sensor was diagnosed. The fan definitely wasn't working and it is now!

The previous overheats were very dramatic with no warning. All fine, then 120 deg with steam everywhere.

This time I had time to see the gauge rising and pull over safely. Far less water was spat out.

The recovery guy started the engine without the cap on the swift tank, ran it back up to speed (a couple of minutes as already hot) and then water bubbled out of the tank. Bad I'm told? We had just filled it up, so it would have been overfilled.

Here's hoping. An expensive fix will almost definitely mean my exit from TVR ownership after 6 massively enjoyable years and it something I really REALY don't want to do...

Edited by page3 on Sunday 10th August 18:29

[GreenV8S]

If the pressure cap isn't holding pressure then the pump will tend to cavitate at speed when it's hot, leading to poor coolant circulation which makes the problem get worse and worse. It may be a quite trivial problem such as a weeping pressure cap ultimately causing the problem.

[tubbystu]

What state is the rad in ? Might need flushing or re-coring ?

Reduced radiator active surface area means the water entering the system is already above the right temperature range, engine temperature rises and on it goes.....

Is it a V6 or a V8 ?

[page3]

v6. Radiator replaced about 4 years ago.

Thanks all for the ongoing advise- it really does help

[mikee boy]

Oil and water clear is a VERY good sign, and the V6 all-iron engine is fairly bullet proof. My S2 overheated for years until I finally cured it and the headgasket never went. I'd suspect the cooling system.

As above regarding cavitation if the system is not correctly pressurised: I've had this on my S2 and a Rover, both when the car slowed down after a long run. Make sure BOTH caps are working, they're only cheap replace them both as it very hard to tell from a visual inspection.

Also, make sure there are no air blocks in the system (do you have a copy of the correct procedures?).

Also, check that the radiator flows freely and that the bottom hose gets hot (checks that the rad flows and that the waterpump is working).

[pies]

GreenV8S said:

If the pressure cap isn't holding pressure then the pump will tend to cavitate at speed when it's hot, leading to poor coolant circulation which makes the problem get worse and worse. It may be a quite trivial problem such as a weeping pressure cap ultimately causing the problem.

Surely a quick test then is to swap the caps over

[markbigears]

Any sign of water around the front of the engine? This would indicate a faulty water pump.

[page3]

Will be calling my mechanic today.

I think best course of action is:

1. get mechanic to check for head gasket failure, if present then ponder long and hard. Do I have any comeback on the previous garage who replaced both 9 months ago?

2. If not, then get full diagnostics, but replace swirl tank and expansion caps anyway as they are cheap.

3. replace water pump as not too expensive, but hope this is the actual problem!

4. Is it worth replacing all hoses as well if there not too expensive?

Edited by page3 on Monday 11th August 09:25

[jev]

I have told him to replace the pressure cap but does he listen to me....

[page3]

Went to fill the car up with water, ready to be collected on Wednesday.

Slight hiss on swirl cap removal and took a good few litres. No water on the garage floor. No oil in the water. No contamination in the oil.

Just hoping for some good news on Wednesday. S's are not meant to sitting quietly away in a garage.

[Jed-S]

jev said:

I have told him to replace the pressure cap but does he listen to me....

I don't think some people appreciate just how important the pressure cap is to the whole cooling system. For the sake of 3 quid it has to be the first thing to be replaced.

With a fully working pressure cap the swirl pot will never be low on water when you check it at cold. If it is then replace the cap as the first step in diagnosing the problem.

Jed

[page3]

Jed-S said:

jev said:

I have told him to replace the pressure cap but does he listen to me....

I don't think some people appreciate just how important the pressure cap is...

Its not that at all, it that he's my brother so I don't listen on principle

We do find it amusing that the Tamora has become the reliable backup vehicle.

Ps. cap ordered. It was checked and found to be 'ok' when the car was fixed last time, so I didn't bother then.

Edited by page3 on Monday 11th August 20:22

[Barkychoc]

You also need the rubber washer under the cap - this doesn't come as standard and on mine has been carefully crafted from a bit of bike inner tube

If it is missing everytime it gets up to temp it pushes water out of the cap - then when it cools it doesn't suck the water back in - it sucks in air instead. Over time your swirl pot level goes down.

[M@H]

page3 said:

The recovery guy started the engine without the cap on the swift tank, ran it back up to speed (a couple of minutes as already hot) and then water bubbled out of the tank. Bad I'm told? We had just filled it up, so it would have been overfilled.

I have met many recovery agents who's standard answer is "head gasket gone" when they really haven't got a &*%&ing clue. There will doubtless have been air further down the system as a result of your spillage, then if you fill it back up without bleeding it properly (again many a recovery agent seems a bit challenged if they do not see a familiar set of bleed nipples) then there will still be air caught in dead areas in the cooling system. Then amazingly so (!) once the engine gets hot again and the air circulates back into it from the rad/hoses etc it expands and "tadaa" you get water and air bubbles from the expansion tank.. air gets MUCH bigger when it gets hot

I'm sure its fine.

Cheers
Matt.

Edited by M@H on Monday 11th August 21:07

[clarenceboddiger]

It may sound obvious but is the thermostat opening??? or should I say opening fully?

[page3]

Faulty water pump!

Head gasket test was fine

[tubbystu]

page3 said:

Faulty water pump!

Head gasket test was fine

Good news then - sort of.

[Roy C]

Better than getting the heads off (again).