Help, overheated last night

Help, overheated last night

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Discussion

No 1

Original Poster:

225 posts

251 months

Wednesday 25th June 2003
quotequote all
As I was driving down the motorway last night, doing about 90mph at about 9pm - nice cool air - I noticed a whiff of coolant. I looked at the temp gauge and, as it was reading around 70deg, thought it couldn't be me. Fortunately, Moto was following as we were travelling back from Donny Park, and he flashed me over. As I pulled onto the hard shoulder, there was a stream of water under the car, yet the fans weren't on.

Initial thoughts were that a pipe had split, but that wasn't the case. After allowing the car to cool a little, I loosened the blue pressure cap and sure enough, the water was red hot. We left it to cool a little more and removed the blue cap, no water inside. I topped it up with what little I had in the car (Evian, no less) and started it up. Again there were no visible leaks, although the temp gauge had gone up to about 90deg - still no fans. As I was only about a mile and half from home, I limped back and deposited the car in the garage.

When I got back from work this evening, I half filled the expansion tank and started the car up. I turned the heater on and within a few minutes, the temp was up to about 80deg and there was loads of heat coming through the heater. I didn't want it to get too hot I shut it off and left it be, but I'm still not sure a) what the problem was last night, and b) whether it is still a problem or whether the car has fixed itself, as only TVR's can.

Has anyone had a similar experience, or have any idea what the problem is?

The car is a Griff 500 LE, so has 2 cooling fans, and according to The Bible, separate circuits for each fan - although I haven't confirmed that yet. One thing that is interesting though, is the otter switch is not on the bottom of the swirl tank as expected - any ideas where that might be?

Also, is the temperature gauge on top left hand side of radiator, or that is something else?

I would appreciate any help you can give as I don't like to see my pride and joy in dry dock with the bonnet up.

No 1

Original Poster:

225 posts

251 months

Wednesday 25th June 2003
quotequote all
OK, slight update. I've just run the car up to heat again, and at 90deg, the fans kicked in for about a minute, then stopped. So it clearly isn't the otter switch, where-ever it may be hiding!

Is it possible that the thermostat stuck closed for some reason? When it happened last night we had been driving for about 30mins so can't see why it should be closed anyway?



Now I'm really confused.

simpo one

85,526 posts

266 months

Wednesday 25th June 2003
quotequote all
If I overfill my expansion tank ('97 500) the car promptly poots it out if I drive even 20 feet into the garage. Never found where it comes from! Could the bit where your temp went from 70 to 90 simply have been the heatsoak while you were parked?

simon.b

1,230 posts

283 months

Thursday 26th June 2003
quotequote all
It could be the pressure seal in the blue cap that has gone and is allowing water to vent at a lower than normal pressure. The cap on my Griff has to be quite tight for it to seal properly.

New caps are available from VW/AUDI dealers at around £10 a go.

Cheers,

Simon.

Stig

11,818 posts

285 months

Thursday 26th June 2003
quotequote all
simon.b said:
It could be the pressure seal in the blue cap that has gone and is allowing water to vent at a lower than normal pressure. The cap on my Griff has to be quite tight for it to seal properly.

New caps are available from VW/AUDI dealers at around £10 a go.

Cheers,

Simon.


Good call. The cooling system won't work if the coolant isn't held under pressure. Sometimes the simplest (and cheapest) solutions are the ones that work.

IPAddis

2,471 posts

285 months

Thursday 26th June 2003
quotequote all
simon.b said:
It could be the pressure seal in the blue cap that has gone and is allowing water to vent at a lower than normal pressure. The cap on my Griff has to be quite tight for it to seal properly.

New caps are available from VW/AUDI dealers at around £10 a go.

Cheers,

Simon.


I had exactly the same thing. 200 miles into a motorway journey and all of a sudden, the Griff turns into an industrial steam cleaning machine. Green coolant all over the engine bay. Topped it up and drove it gingerly home with no problems what so ever. Replaced the blue coolant cap just to be sure and it's been fine for 3 years since.

Maybe it just had a cold and needed a sneeze?

Ian A.