Still running hot after new thermostat

Lucknow Landy said:

Hi Landy fans. I'd appreciate any pointers on what to try next with my series 3, 6 cylinder petrol which I have been sorting over the last couple of years. It always ran with temp gauge nicely mid range but last month suddenly the needle went to the red zone after warming. This was after a session of tinkering under bonnet so thought an electrical issue could be the cause but see no loose wires. The fuel gauge read normal so I thought not a voltage stabiliser issue so installed a new temp sensor. This remedied things to a v small extent; the needle hovered 90% of the way up to red zone. Tried a second temp gauge and it too showed high temp. As an experiment, I removed the thermostat and this fixed the issue with the gage reading in the mid range (as had usually need the case). But I did not want to run without a thermostat indefinitely so bought a new, high flow unit. As soon as I fitted this new thermostat, back to the old problem with needle close to red. Did I simply buy a dud thermostat? I should have tested it before fitting as removing the housing involves multiple fiddly bolts since the PO fitted the alternator mount to one of the housing bolts. Any thoughts? Out with the spanners, remove and test the new thermostat or am I overlooking another possible cause?

Click to expand...

Lucknow Landy said:

Thanks for the quick responses and welcome guys. I have reposted my Q in the 'series' area of the site and here is a pic taken at last week's Gnoo Blas Classic in NSW Australia (my local club's annual event).

View attachment 310849
Thanks for the answer Diddypud. Yeah, pretty confident I fitted the new thermostat the right way up. It does not have a collar but was the one that the computer system at my local store reckoned was right (!). It's one from Tridon but no temp is give on the pack. I have pasted a link to that thermostat in below. Just for now I'll hold off from flushing the cooling system as my landy has been used at least weekly the last two years and good as gold before this issue. Hoses all look fine too. Still suspect I am overlooking something that's caused this issue to suddenly arise. For now I'll take out the new thermostat and test the hypothesis that the prob arose because the new one is a dud that fails to open fully (and the old unit failed and stuck closed). Cheers.

land rover series three petrol thermostat tridon high flow - Google Shopping

www.google.com

Click to expand...