Overheating Griff trauma.

[Mark 4.3]

Can anyone advise on likely causes of overheating? Griff had developed a slightly erratic temp guage over last 4 days (it has had 3 weeks rest whilst I was on honeymoon). It heads quickly towards 100-110 deg from cold, but just as quickly stabilises then appears ok for the short trips I have made. Went for a 50 mile run yesterday, with same initial pattern, but no problems. Parked up for 2 hours then restarted, but temp went crazy after a few minutes and I had to stop and let off steam. Noticed fans wouldn't kick in, so managed to bypass the thermostat just by connecting the 2 cables. Smugly restarted my journey to find that although fans were working well, car was still overheating. Then realised the rad was COLD. No obvious leaks spotted anywhere, and expansion tank was about 1/3 to 1/2 full. I had spotted small drops of coolant on gargage floor, but not enough to cause alarm (it that normal?) I am guessing water pump is to blame, or maybe just an airlock or blockage? Anyone have similar experience? Also I am looking for a replacement cigarrette lighter - tried std Vauxhall and Alfa but both about 1-2mm too wide - can anyone explain where to obtain a 'narrow model' for my 1992 car? Thanks for any advice...

[steve-p]

If the rad is cold then it sounds more like a stuck thermostat. Usually they stick in the open position so that the car just never properly warms up in the winter. However they can stick in the closed position too, which means no water circulates through the radiator.

[steve-p]

I should also add that if the thermostat is stuck closed, on no account should you drive the car because major overheating is very serious indeed for Rover V8s. However, you could allow the car to tick over for a short period, carefully making sure that it isn't overheating (yet), and give the thermostat a few taps with a blunt instrument. It might unstick itself.

[tav]

Had exactly the same symptoms on a non TVR car a few weeks ago and as previously said it was the thermostat that had stuck shut. Nice Mr. AA man tested the water to make sure the head gasket had not blown and then ripped the internals of the thermostat out and replaced it, allowing me to get home. His wordly advice being that you should never just remove the thermostat as the restricted opening plays some function in the system (if that makes sense). Cheep job for me to sort out, hope yours is too.

[budd]

Sounds like you need to give the cooling system a thorough once over I'd start by checking the thermostat
then the water pump also check for collapsed or perished hoses slowing or blocking water flow.I had the some problem and traced it to the Rad,which was blocked up with Rad weld.I have found that the std cooling system is up to the job of cooling the big V8 but needs to be in tip top condition,using a product like Redlines water wetter or Millersoils Rad Hib extra cool helps,by controling corosion within the system hope this helps.

[kevinday]

If you do tap it with a blunt instrument make sure it is a 'soft' blunt instrument such as a rubber mallet, otherwise you could fracture the casting. My preference would be to simply replace the thermostat anyway, its a cheap option!

[davidd]

I had a similar problem when my rad started to leak last year.

Obvious things to do are to make sure there are no airlocks in the system, check the thermostat and fans are ok and check the rad for leaks.

Good luck

D.

[shpub]

Sounds like a stuck thermostat. Please fit the TVR one and not a Rover one otherwise you will get more overheating problems. Drill a few 1/8 or 3/16 holes to allow some water to bypass it.

The thermostat does not control the fans. The switch that does this is called the otter switch.

Steve
www.tvrbooks.co.uk

[Scoobysnack]

As an aside, I was at a TVR garage yesterday and they told me the Griffith has improved cooling after late 1996 ???? i seem to recall him mentioning larger fans?

Anyone else know?

J

[shpub]

quote:
As an aside, I was at a TVR garage yesterday and they told me the Griffith has improved cooling after late 1996 ???? i seem to recall him mentioning larger fans?

Anyone else know?

J

The Griffis have had single fans. double fans, Cerbera fans, fans with shrouds, fans without shrouds. The serpentine engined cars have a different cooling system than the pre-serps and some have expansion tanks and swirl tanks and some don't.... Apart from all this they are exactly the same!

Why?

Steve
www.tvrbooks.co.uk

[beano1197]

When not hooning around in the Griff, I have been known to build PCs (some have even worked!). But that made me realise that it is not just down to how big the fan is..........

....so whatever your reason for asking, the answer isn't necessarily "bigger".....

....unless your question is "which is the best size engine?"

[david beer]

I have a 99 griff 500 that i could not keep the the temp down until i rewired. Now i have a two speed fan system that i can keep the temp down to where it should be.There is a 20-25% increase available, similar to the lighting issue.

>> Edited by david beer on Tuesday 10th September 18:59

[Guillotine]

check the hose at the top of the block, infront of the thermostat housing. if the hose stays cold or is only "warm" the probs in the thermostat / blockage area. if it gets hot, the t'stat is opening and the problem is in the rad area. waterpump / ciculation could be both as with airlocks blockages but it will still get warm. the hose should get so hot you can hardly hold it! and very quickly when the t'stat opens!
ditto all the other info.
by the way, and air lock behind the t'stat will keep it closed sometimes. just a thought.

[Mark 4.3]

Thanks to everyone for these useful comments. The problem turned out to be nothing more than a loose hose clip at the rad end, which allowed a huge airlock in the system. Just been for a run through town and it is going up to 90-92 deg, then cooling to ~87. So appears to be working well... for now!