Hot and bothered!

[griffmad]

Dear all,

Whilst driving home the other night I could here the old Griff pinking slightly under low load, c.2700 revs, in 3rd, 4th and 5th. Wasn't overly concerned and suspected a bad dose of fuel, although it was running a little warmer than usual for a motorway run.

Checked the water when I go home and found nothing sinister. Drove to work the next day and noticed that the water temp got up to 90 rather quickly and was still pinking slightly ....
However, 5 mins into my journey home the temp had gone well past 90 and hit nearly 120, at which point I pulled over and called for help.

It took an hours or so to cool down at which point I re-checked the water level, granted the level had dropped but was still about 1/4 of the way up the expansion tank. The RAC turned up without the requested flatbed and could do nothing constructive, other than follow me home slowly.

Anyways the car got hot quickly again so I pulled over. I chanced my arm and loosened the top of the expansion bottle expecting boiling water to cover me ... but to my surprise there was little or no pressure ????? Both fans had come on again so nothing strange there ....

Any ideas gratefully appreciated ....
... thermostat? water pump?

Cheers

Rich

[shpub]

Check that the water is not going into the oil and creating mayo. If so. Don't drive the car and take it to hospital and pray that it is only a head gasket and that the heads have not warped.

Another possibility is exhaust gases getting into the coolent and pressurising the system. The gas causes water to heat very quickly and the gases pressureise the system and force water out. Again new head gasket. Same advice applies.

Steve
www.tvrbooks.co.uk

[shpub]

Could also be the thermostat as you say. If the rad stays cool and you can't feel hot water flowing through it then that could be the problem. Surprised that the RAC man didn't check.

[griffmad]

Cheers Steve,

Checked for the dreaded mayo and was extremely relieved to find none so hopefully not head gasket ...

Will start the ball rolling with the thermostat me thinks!

Thanks

Rich

[GreenV8S]

If the water level has got really low, you can get air into the pump which then stops pumping. Assuming no other damage from the overheating, this would be fixed just by filling up and bleeding the system. Makes you wonder where all that water went though - definitely keep an eye on it after you've filled it up.

[griffmad]

... the old girl still isn't right.

Replaced the thermostat which cured the overheating issue but the car was still pinking like a good'un under low load at around 2-3k revs.

Sent the car in yesterday and ended up retarding the timing very slightly which perhaps not surprisingly has stopped it pinking but has now left it running flatter than a very flat thing.

Can't help but think the pinking and orginal overheating problem are related!

Any thoughts chaps ????

A confused Rich

[icamm]

What fuel do you use? Try Optimax if you don't already use it.

[2 sheds]

Could be that the cylinders are overheating ,this would cause pinking, ie the water jackets in the block are not getting a good flow if any.
Maybe water pump problem.
Tim

[griffmad]

Water pump is last resort hopefully .....
.... looks like there has been a bad batch of fuel from the Shell plant at Ellesmere Port, so potentially its actually the Optimax thats causing the problem ....

Will report back when resolved!

Cheers

Rich