My temperature never gets past a 1/4, I’ve read loads of threads on here and elsewhere so far I’ve blanked off the egr thermostat at the same time as fitting a egr delete (which didn’t make any difference )
I’ve looked at the wiki for the main thermostat which says 4-6 hours! But I’ve also heard people fitted a Renault 5 in-line stat to the top hose which is supposed to take no more than 1/2 hour! Has anyone done that?? If so is there a write up for it anywhere??
Thanks

Great minds think alike - I asked the very same question a few days ago in this thread: https://www.fullfatrr.com/forum/topic50700.html (scroll about half-way down the page to the latest messages).

I've got the bits coming to try it. I'm getting a new hose to fit the thermostat in, then I've still got the original hose in case it all goes wrong. Current worry is removing the 'quick release' connector from the water outlet on the engine. I've read these types of connectors can be anything but 'quick release' after a few years service and I'm very concious that the water outlet on the engine is only plastic and could be brittle by now. Might leave the quick release connector in place and use a dremmel to cut through the metal clip holding the hose to the connector, which I'll replace with a jubilee clip.

If you could take some pictures that would offer any help that would be great 👍

Just curious, how do you fix the Renault thermostat in place? Jubilee clip over the outside of the hose?

Jubilee clip over hose as per renault.

The thermostat used is more of a short tube shape than the usual flying saucer shape, so it can't 'tip over' in the hose so to speak. Just need something to stop water pressure pushing it further up the hose, and a jubilee clip is used as kds2 stated. Although it seems likely that it's such a tight fit in the hose it isn't going to go anywhere anyway ...

Thanks.
Interesting modification. Might well have done that instead of changing the engine thermostat if I had known about it.
Will note for future.

How does this work if the engine thermostat is goosed

The engine thermostat is goosed because it is stuck fully open allowing full coolant flow thereby not allowing the engine to heat up correctly. Using a separate thermostat allows the engine to heat as normal.

Ah I see so with this mod the new thermostat is closed then the engine warms up?

That's it. The supplementary thermostat simply replaces the function of the faulty engine thermostat.

Or to refine the answer slightly, the main thermostat opens at too low a temperature, which lets coolant through the radiator which overcools the engine. A second thermostat is placed in the engine end of the top radiator hose such that, even though the main thermostat has opened, coolant can't pass through the radiator until the coolant in the engine block reaches ~88°C and the second thermostat opens.

Try this:
Temp under 10.

Cover the radiator or the front grill. Drive it. If the temp goes up and stays up, you need new main thermostat. If it doesn’t change anything then you need new gearbox oil cooler. There is thermostat inside.

I've just clamped my top radiator hose flat between two small bits of wood to test what happens on a quick trip round the local roads - gauge rises to 12 o'clock and stays there. Remove clamp and gauge returns to normal position of about 10:30. Engine warmed up surprisingly quickly with the clamp on, compared to what I'm used to.

Have got the thermostat fitted in a new hose ready for fitting. Popped the end of the hose in a jug of boiling water for a couple of minutes to soften, lubed with Fairy Liquid, and used a piece of plastic sink waste pipe to push it in. That bit was simple.

New hose fitted and temperature gauge now sitting nicely at 12 o'clock. Only been round local roads at the moment, need to check it on a longer run.

The quick release connector at the radiator end came apart fairly easily. At the engine end, I got the connector to move about 2mm but it refused to come apart (yes, I had slid the securing wire to the release position!). Spent about an hour trying to wiggle it apart (with a break for a cup of tea). Gave up in the end and got out the Dremmel with a flexible drive shaft. Cut through the hose clip at a 45° angle then the old hose was easy to remove. Removing the bolt that secures the dip stick tube to the inlet manifold gives you a little bit more room. New hose was easy to fit, using a small ring spanner to tighten the jubilee clip.